Unnamed: 0
int64 0
2.34M
| title
stringlengths 5
21.5M
| abst
stringlengths 1
21.5M
|
|---|---|---|
1,400 | Antiarrhythmic Drugs. | Both supraventricular and ventricular arrhythmias are associated with increased mortality and morbidity. Numerous antiarrhythmics have been developed in an attempt to decrease the frequency of these arrhythmias, hoping to improve survival and improve quality of life. Antiarrhythmic agents are a diverse group of drugs that affect various cardiac ionic channels and block specific arrhythmias. However, despite the suppression of these potentially lethal cardiac arrhythmias, only the beta blockers have been shown to reduce sudden arrhythmic death, especially in patients with prior myocardial infarction or heart failure. Some antiarrhythmic agents can also worsen the index arrhythmia and caution must be used especially in the compromised patient. A simple guideline is as follows: For conversion of atrial fibrillation or flutter to sinus rhythm, in the absence of structural heart disease, intravenous ibutilide or oral propafenone or flecainide are good choices. For maintenance of sinus rhythm, propafenone or flecainide are logical choices. In the presence of structural heart disease, amiodarone, dofetilide, or dl sotalol are preferred. In heart failure, dofetilide or amiodarone are the logical choices. The role of antiarrhythmic therapy for ventricular arrhythmias is questionable and may be contraindicated, except for the use of beta blockers. The implantable cardioverter-defibrillator is often used in patients at high risk. At times, the addition of an antiarrhythmic agent such as amiodarone may be justified. |
1,401 | Atrial fibrillation in cats: 50 cases (1979-2002). | To determine signalment, clinical signs, diagnostic findings, treatment, and outcome for cats with atrial fibrillation (AF).</AbstractText>Retrospective study.</AbstractText>50 cats.</AbstractText>Medical records of cats that met criteria for a diagnosis of AF (ECG consisting of at least 2 leads, clear absence of P waves, supraventricular rhythm, and convincingly irregularly irregular rhythm) and had undergone echocardiography were reviewed.</AbstractText>There were 41 males (37 castrated) and 9 females (7 spayed). Forty-one were of mixed breeding; 9 were purebred. Mean +/- SD age was 10.2 +/- 3.7 years. The most common chief complaints were dyspnea, aortic thromboembolism, and lethargy. In 11 cats, AF was an incidental finding. Mean +/- SD ventricular rate was 223 +/- 36 beats/min. The most common echocardiographic abnormalities were restrictive or unclassified cardiomyopathy (n = 19), concentric left ventricular hypertrophy (18), and dilated cardiomyopathy (6). Mean +/- SD left atrial-to-aortic diameter ratio (n = 39) was 2.55 +/- 0.80. The most common thoracic radiographic findings were cardiomegaly, pleural effusion, and pulmonary edema. Median survival time (n = 24) was 165 days (range, 0 to 1,095 days). Eight of 24 cats lived for > or = 1 year after a diagnosis of AF was made.</AbstractText>Results suggest that AF occurs primarily in older adult male cats with structural heart disease severe enough to lead to atrial enlargement. Atrial fibrillation in these cats was most commonly first detected when signs of decompensated cardiac disease were evident, but also was commonly identified as an incidental finding.</AbstractText> |
1,402 | [Perspectives and limitations in the treatment of vagus-induced atrial fibrillation. Insights from cellular pharmacology]. | Pharmacological treatment of atrial fibrillation (AF) is limited by induction of malignant ventricular arrhythmias. Developing new drugs, a promising strategy is a more specific treatment of the atria. Muscarinic potassium current (IK[ACh]) is predominantly expressed in supraventricular tissue and mediates the induction of vagus-induced AF. The authors investigated the profile of representative class III drugs in respect to their effect on IK(ACh).</AbstractText>In rat atrial myocytes, IK(ACh) was activated by acetylcholine (ACh) measured with the whole-cell voltage clamp method. Drugs used: selective IKs blocker chromanole 293B (Cro); IKr blockers sotalol (Sot), dofetilide (Dof), ibutilide (Ibu), and terikalant (Ter). Data are expressed as mean values +/- standard deviation (SD).</AbstractText>ACh-induced IK(ACh) density was 73 +/- 9 pA/pF (n= 9). IK(ACh) was almost completely desensitized in the presence of 50 micro M Ter, Ibu, or Dof. IC(50) of IK(ACh) inhibition by the three drugs was 0.9, 2.8, and 4.2 micro M (Dof, Ibu, and Ter, respectively). Receptor-independent GTP-gamma-S-induced IK(ACh) was sensitive to Ter, Ibu, and Dof as well. Sot is known to be a weak inhibitor of IKr. Inhibition of IK(ACh) by Sot was much less potent (IC(50) = 35.5 micro M) than inhibition by the high-affinity IKr blockers Ter, Ibu, and Dof. Superfusion of the cells with the IKs blocker Cro showed no desensitization of IK(ACh). Applied via the patch pipette (< 40 min) none of the class III drugs were effective.</AbstractText>The results indicate inhibition of IK(ACh) and IKr but not IKs to be of similar mechanism (direct ion channel inhibition from the external side of the membrane). Potent desensitization of muscarinic potassium current could be of clinical relevance especially in patients with vagus-induced AF.</AbstractText> |
1,403 | Suppression of paroxysmal atrial tachyarrhythmias--results of the SOPAT trial. | The indication to treat paroxysmal atrial fibrillation (PAF) is controversial. The Suppression of Paroxysmal Atrial Tachyarrhythmias (SOPAT) trial was designed to answer the following questions: (1) What is the average rate of spontaneous events of symptomatic PAF with and without anti-arrhythmic medication? (2) what is the prevalence of severe side-effects? and (3) is the fixed combination of Quinidine + Verapamil inferior to the efficacy of sotalol or not?</AbstractText>Within 60 months 172 centres in Germany, Poland, and The Slovak Republic prospectively enrolled 1033 patients (mean age 60 years, 62% male) with documented frequent episodes of symptomatic PAF. Patients were randomised to either Quinidine + Verapamil 480/240 mg/d (high dose; 263 patients), Quinidine + Verapamil 320/160 mg/d (low dose; 255 patients), Sotalol 320 mg/d (264 patients) or placebo (251 patients), of which 1012 patients entered the intention-to-treat analysis. The primary endpoint was the time to first recurrence of symptomatic PAF or premature discontinuation. Secondary outcome parameters were the total number of symptomatic episodes and tolerability of the tested drugs. Patients were followed for a period of up to 12 months by daily and symptom-triggered trans-telephonic ECG-monitoring (Tele-ECG). The mean time under treatment was 233 +/- 152 days. Regarding the primary endpoint, all active treatments were superior to placebo and not different from each other. A total of 756 patients reached the primary endpoint within 105.7 +/- 8.7 d (mean +/- SEM) in the placebo group, vs. Quinidine + Verapamil (high dose) (150.4 +/- 10 d, p = 0.0061), vs. Quinidine + Verapamil (low dose) (148.9 +/- 10.6 d, p = 0.0006), vs. Sotalol (145.6 +/- 93 d, p = 0.0007). All three treatments were also effective in the reduction of AF burden (days with symptomatic AF [%] mean +/- SD, p vs. placebo): Quinidine + Verapamil (high dose) (3.4 +/- 12, p = 0.0001), Quinidine + Verapamil (low dose) (4.5 +/- 12.3, p = 0.008) and Sotalol (2.9 +/- 6.5, p = 0.026) compared to placebo (6.1 +/- 13.5). A total of four deaths, 13 syncopes, and one ventricular tachycardia (VT) occurred during the active study period, of which one death and one VT were related to Quinidine/Verapamil.</AbstractText>Taken together, anti-arrhythmic therapy with the fixed combination of Quinidine + Verapamil is as effective as Sotalol in the reduction of the recurrence rate of symptomatic PAF with a low but definite risk of severe side-effects.</AbstractText> |
1,404 | The anaesthetic management of a parturient with polymorphic catecholamine-sensitive ventricular tachycardia. | Polymorphic catecholamine-sensitive ventricular tachycardia is an uncommon but potentially life-threatening condition. There are few reports of this condition in pregnancy. It is one of five types of polymorphic ventricular arrhythmia, the others being long-QT syndrome, short coupled variant of torsade de point malignant disease, idiopathic ventricular fibrillation with normal ECG and Brugada syndrome. Exercise and stress can precipitate ventricular tachyarrhythmias in patients with polymorphic catecholamine-sensitive ventricular tachycardia and it is important to avoid increases in plasma catecholamine levels. We report on the anaesthetic management of a parturient with this condition, for elective caesarean section and discuss the stress response in parturients receiving regional and general anaesthesia. |
1,405 | Accelerated idioventricular rhythm during spinal anesthesia for cesarean section. | During cesarean section under regional anesthesia various anomalies of the electrocardiogram are reported such as bradycardia, supraventricular and ventricular premature beats, supraventricular paroxysmal tachicardia, S-T depression non-significant for myocardial ischemia and second degree atrioventricular block. We describe two cases of accelerated idioventricular rhythm in patients undergoing elective cesarean section with spinal anesthesia of which we have not found mention in the literature. This arrhythmia is not dangerous and does not usually evolve into ventricular fibrillation. During spinal anesthesia, however, it can exacerbate hypotension and, if misdiagnosed, a further administration of ephedrine can increase the duration of accelerated idioventricular rhythm. When necessary, for example in symptomatic hypotension or severe bradycardia, atropine is advised in order to inhibit vagal tone and increase the activity of the sino-atrial node, obtaining a pharmacological overdrive. This therapy is appropriate even if the frequency of the accelerated idioventricular rhythm is high. |
1,406 | Pregnancy and Kawasaki disease. | The management of a pregnant mother at 20 weeks' gestation presenting with ventricular fibrillation and her subsequent elective caesarean section at 38 weeks' gestation are described. Investigation showed the presence of coronary artery aneurysms due to Kawasaki disease. The pregnancy was further complicated by placenta praevia (grade IV). |
1,407 | Effects of endothelins on cardiac and vascular cells: new therapeutic target for the future? | The predominant isoform of the endothelin peptide family. endothelin-1 (ET-1) exerts various biological effects. These include effects on arterial smooth muscle cells causing intense vasoconstriction and stimulation of cardiac cells. ET-1 promotes changes in cardiomyocytes that are consistent with electrical remodelling such as changes in ionic current density and inhomogeneous prolongation of action potential duration resulting in increased dispersion. As for the underlying mechanisms, ET-1 was shown to suppress several cAMP-dependent ionic currents, such as ICa, IK and ICl in various mammalian cardiac preparations including human myocytes; however, the degree of suppression of these currents is different and highly dependent on experimental conditions. The proposed arrhythmogenic effects of ET-1 may also involve enhancement of Ca2+ release from intracellular stores, generation of IP3, and acidosis due to stimulation of the Na+/H+ exchange. Furthermore, ET-1 acts as the natural counterpart to endothelium-derived nitric oxide, which exerts vasodilator, antithrombotic and antiproliferative effects, and inhibits leukocyte adhesion to the vascular wall. Effects of ET-1 are mediated through interaction with two major types of cell surface receptors. ETA receptors have been associated with electrical remodelling, vasoconstriction and cell growth, while ETB receptors are involved in the clearance of ET-1, inhibition of endothelial apoptosis, release of NO and prostacyclins, and inhibition of the expression of ET-1 converting enzyme. The derangement of endothelial function in various cardiovascular diseases, such as cardiomyopathies, hypertension or arteriosclerosis, is a crucial element of the pathomechanism, thus ET receptors are considered as important therapeutic targets. Indeed, ET receptor antagonists may be able to preserve or restore endothelial integrity and may have antiarrhythmic properties; therefore, they are promising tools in cardiovascular medicine. |
1,408 | Diabetic cardiomyopathy: electromechanical cellular alterations. | Diabetic patients show a higher incidence of cardiac arrhythmias, including ventricular fibrillation and sudden death. However, although diabetic cardiomyopathy is a frequent and important complication of diabetes mellitus, its physiological basis is not completely known. The electrocardiogram of diabetic patients shows several alterations from normal patterns, most of them related to the QT interval and T wave. Recently, different alterations in cardiac ionic currents have been described in myocytes isolated from diabetic hearts, mainly a reduction in potassium repolarizing currents. Three different mechanisms could be involved in these alterations. First, direct metabolic alterations of the cardiac myocyte, such as impaired activity of protein kinases and phosphatases, intracellular pH regulation, intracellular calcium handling, and others. Second, impaired support of extra cardiac factors regulating cardiac activity, such as sympathetic regulation of heart rate and contractility. Thus, diabetic autonomic neuropathy leads to diminished noradrenaline release in cardiac ventricle in response to standing, exercise or cold stress. Besides, diabetic cardiomyopathy reduces cardiac myocyte response to acute noradrenaline exposure and finally, impairs support of different trophic factors responsible for the regulation of ionic channel expression. Thus, basal noradrenaline release in the ventricles, necessary to maintain adequate potassium channel expression, is reduced by sympathetic neuropathy. Moreover, the levels of insulin and other trophic factors required for the maintenance of adequate ionic channel expression are also altered in diabetic patients. Therefore, different physiopathological mechanisms are involved in diabetic cardiomyopathy. Thus, further research is needed in order to prevent the development of this long-term complication, and to improve the pharmacological management of diabetic patients. |
1,409 | Recent developments in cardiovascular drug therapy: treatment of atrial arrhythmias with new class III drugs and beyond. | Despite recent advances in non-pharmacologic approaches antiarrhythmic drugs still play a dominant role in the treatment of cardiac arrhythmias. Large randomized controlled clinical trials have pointed out the importance of a proper benefit to risk evaluation in various patient subsets. This led to a continuous decline in the use of sodium channel blockers due to their possible proarrhythmic effects particularly in patients with reduced left ventricular function and ischemic heart disease. On the contrary, beta-blockers and more complex class III compounds such as sotalol and amiodarone have been prescribed increasingly. However, side effects commonly observed boosted the development of agents with simpler ion channel-blockade and less adverse reactions. In this review newer so-called "pure" class III agents will be discussed. Their common mechanism of action is an antifibrillatory effect both on the atrial and ventricular level. Clinically, they are used in the chemical cardioversion and the prevention of atrial fibrillation or atrial flutter as well as for the maintenance of sinus rhythm after its successful restoration. This report contains a detailed analysis of the pharmacokinetics, results of clinical studies and implications regarding the use in daily practice for three distinct compounds: ibutilide, dofetilide and azimilide. As efficacy is still limited their current and future role in hybrid therapies combining drug therapy with alternative treatment modalities (catheter ablation, pacemakers and implantable cardioverter defibrillators) is discussed. In addition, an outlook for a future drug design implementing changes in electrically remodeled atrial tissue will be given. |
1,410 | Cardiac sarcolemmal ion channels and transporters as possible targets for antiarrhythmic and positive inotropic drugs: strategies of the past--perspectives of the future. | In this article we overview the most important antiarrhythmic and positive inotropic mechanisms based on pharmacological modification of an ion channel or a transport protein in the surface membrane of cardiac myocytes. First we briefly characterize the ion currents mediated by these proteins in atrial and ventricular cells. Since the level of expression of ion channels is markedly altered in various types of chronic heart diseases, such as atrial fibrillation or heart failure, cardiac remodelling characteristic of these cases is also discussed. The paper gives evaluation of the currently applied most important antiarrhythmic strategies and some insight into the perspectives of the future by reviewing a few but promising mechanisms and drugs that are currently investigated. Positive inotropic agents and mechanisms are similarly treated, focusing primarily on proarrhythmic risks or potential antiarrhythmic effects of these compounds. Based on the backgrounds and aims above, modification of the followings factors is discussed in details: I(Na), I(Ca), I(Kr), I(Ks), I(Kl), I(to), I(Kur), I(K,Ach), I(K,ATP), I(f), gap-junction channel, Na(+)/K(+) pump, Na(+)/Ca(2+) exchanger, Na(+)/H(+) exchanger, as well as the intracellular concentrations of sodium and calcium ions. In addition to the critical evaluation of each manipulation, the following general conclusions can be drawn. (1) Since large modifications in action potential parameters are usually disadvantageous at long time scale, combination of the various mechanisms, each represented at a moderate degree, appears to be better. (2) Regarding Class III. antiarrhythmic action, selective potassium channel blockers free of reverse rate-dependent properties should be preferred. (3) Partial inhibition of the Na(+)/Ca(2+) exchanger may result-paradoxically in an antiarrhythmic action under specific conditions, in addition to its positive inotropic effect. We believe that investigation of new antiarrhythmic mechanisms, rather than new compounds of the old families, might be most beneficial in order to effectively treat life threatening cardiac arrhythmias in the future. |
1,411 | Protection against ventricular arrhythmias and cardiac death using adenosine and lidocaine during regional ischemia in the in vivo rat. | Despite decades of research, there are few effective ways to treat ventricular fibrillation (VF), ventricular tachycardia (VT), or cardiac ischemia that show a significant survival benefit. Our aim was to investigate the combined therapeutic effect of two common antiarrhythmic compounds, adenosine and lidocaine (AL), on mortality, arrhythmia frequency and duration, and infarct size in the rat model of regional ischemia. Sprague-Dawley rats (n = 49) were anesthetized with pentobarbital sodium (60 mg.ml(-1).kg(-1) i.p.) and instrumented for regional coronary occlusion (30 min) and reperfusion (120 min). Heart rate, blood pressure, and a lead II electrocardiogram were recorded. Intravenous pretreatment began 5 min before ischemia and extended throughout ischemia, terminating at the start of reperfusion. After 120 min, hearts were removed for infarct size measurement. Mortality occurred in 58% of saline controls (n = 12), 50% of adenosine only (305 microg.kg(-1).min(-1), n = 8), 0% in lidocaine only (608 microg.kg(-1).min(-1), n = 8), and 0% in AL at any dose (152, 305, or 407 microg.kg(-1).min(-1) adenosine plus 608 microg.kg(-1).min(-1) lidocaine, n = 7, 8, and 6). VT occurred in 100% of saline controls (18 +/- 9 episodes), 50% of adenosine-only (11 +/- 7 episodes), 83% of lidocaine-only (23 +/- 11 episodes), 60% of low-dose AL (2 +/- 1 episodes, P < 0.05), 57% of mid-dose AL (2 +/- 1 episodes, P < 0.05), and 67% of high-dose AL rats (6 +/- 3 episodes). VF occurred in 75% of saline controls (4 +/- 3 episodes), 100% of adenosine-only-treated rats (3 +/- 2 episodes), and 33% lidocaine-only-treated rats (2 +/- 1 episodes) of the rats tested. There was no deaths and no VF in the low- and mid-dose AL-treated rats during ischemia, and only one high-dose AL-treated rat experienced VF (25.5 sec). Infarct size was lower in all AL-treated rats but only reached significance with the mid-dose treatment (saline controls 61 +/- 5% vs. 38 +/- 6%, P < 0.05). We conclude that a constant infusion of a solution containing AL virtually abolished severe arrhythmias and prevented cardiac death in an in vivo rat model of acute myocardial ischemia and reperfusion. AL combinational therapy may provide a primary prevention therapeutic window in ischemic and nonischemic regions of the heart. |
1,412 | Anaesthesia in patients with Brugada syndrome. | Brugada syndrome is characterized by right bundle branch block, ST segment elevation in the precordial leads and sudden death caused by ventricular fibrillation. We present two successful anaesthetic management cases in patients with Brugada syndrome. |
1,413 | Use of ibutilide in cardioversion of patients with atrial fibrillation or atrial flutter treated with class IC agents. | We sought to assess the efficacy and safety of ibutilide cardioversion for those with atrial fibrillation (AF) or atrial flutter (AFL) receiving long-term treatmentwith class IC agents.</AbstractText>Attenuation of ibutilide-induced QT prolongation has been observed in a small number of patients pretreated with class IC agents. The clinical significance of the interaction between ibutilide and class IC agents is unknown.</AbstractText>Seventy-one patients with AF (n = 48) or AFL (n = 23), receiving propafenone 300 to 900 mg/day (n = 46) or flecainide 100 to 300 mg/day (n = 25), presented for ibutilide (2.0 mg) cardioversion.</AbstractText>The mean durations of arrhythmia episode and arrhythmia history were 25 +/- 48 days and 4.4 +/- 6.4 years, respectively. Sixty-five patients (91.5%) had normal left ventricular systolic function. Twenty-three of 48 patients (47.9%; 95% confidence interval, 33.3% to 62.8%) with AF and 17 of 23 patients (73.9%; 95% confidence interval, 51.6% to 89.8%) with AFL converted with mean conversion times of 25 +/- 14 min and 20 +/- 12 min, respectively. There was a small increase in corrected QT interval after ibutilide (from442 +/- 61 ms to 462 +/- 59 ms, p = 0.006). One patient developed non-sustained polymorphous ventricular tachycardia and responded to intravenous magnesium. Another developed sustained torsade de pointes and was treated effectively with direct-current shock and intravenous dopamine.</AbstractText>Our observations suggest that the use of ibutilide in patients receiving class IC agents is as successful in restoring sinus rhythm and has a similar incidence of adverse effects as the use of ibutilide alone.</AbstractText> |
1,414 | Ibutilide added to propafenone for the conversion of atrial fibrillation and atrial flutter. | We evaluated the safety and efficacy of ibutilide when added to propafenone in treating both paroxysmal and chronic atrial fibrillation (AF) and atrial flutter (AFL).</AbstractText>The effects of ibutilide in patients with paroxysmal or chronic AF/AFL who were pre-treated with propafenone have not been previously evaluated.</AbstractText>Oral propafenone was initially given in 202 patients with AF/AFL without left ventricular dysfunction. Intravenous ibutilide was administered in 104 patients in whom propafenone failed to convert the arrhythmia. Two different propafenone dosage regimens were used according to the duration of the presenting arrhythmia: patients with paroxysmal arrhythmia (n = 48) received 600 mg loading dose, and patients with chronic arrhythmia (n = 56) were receiving 150 mg three times a day as stable-dose pre-treatment.</AbstractText>Ibutilide offered an overall conversion efficacy of 66.3% (69 of 104 patients), 70.8% for patients with paroxysmal AF/AFL and 62.5% for patients with chronic AF/AFL. Ibutilide significantly decreased the heart rate (HR) and further prolonged the QTc interval (p < 0.0001). The degree of HR reduction after ibutilide administration emerged as the sole predictor of successful arrhythmia termination (p < 0.001). After ibutilide, one patient (1%) developed two asymptomatic episodes of non-sustained torsade de pointes, and 10 patients (9.6%) manifested transient bradyarrhythmic events; however, all bradyarrhythmic effects were predictable, occurring mostly at the time of arrhythmia termination. None of 82 patients who decided to continue propafenone after successful cardioversion had immediate arrhythmia recurrence.</AbstractText>Our graded approach using propafenone and ibutilide appears to be a relatively safe and effective alternative for the treatment of paroxysmal and chronic AF/AFL to both rapidly restore sinus rhythm in nonresponders to monotherapy with propafenone and prevent immediate recurrences of the arrhythmia.</AbstractText> |
1,415 | A program encouraging early defibrillation results in improved in-hospital resuscitation efficacy. | The purpose of this study was to determine whether survival to discharge after in-hospital cardiopulmonary arrest could be improved by a program encouraging early defibrillation that included switching from monophasic to biphasic devices.</AbstractText>In-hospital resuscitation continues to have a low success rate. Biphasic waveform devices have demonstrated characteristics that might improve survival, and outside the hospital, automated external defibrillators (AEDs) have shown promise in improving survival of patients suffering cardiopulmonary arrest.</AbstractText>A program including education and replacement of all manual monophasic defibrillators with a combination of manual biphasic defibrillators used in AED mode and AEDs in all outpatient clinics and chronic care units was implemented.</AbstractText>With program implementation, the percentage survival of all patients with resuscitation events improved 2.6-fold, from 4.9% to 12.8%. Factors independently predicting survival included event location outside an intensive care unit, younger age, an initial rhythm of pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF), pre-arrest beta-blocker, and program initiation. The outcome was independent of gender, race, work shift, number of previous resuscitation attempts, body mass index, comorbidity index, presence of diabetes, presence of hypertension, or use of angiotensin-converting enzyme inhibitors. The improvement in mortality was attributable solely to an effect on patients presenting with VT/VF. Patients with these initial rhythms were 14-fold (odds ratio = 0.07 of death, confidence interval = 0.02 to 0.3) more likely to survive to discharge after program initiation. Automated external defibrillators performed similarly to biphasic manual defibrillators in AED mode.</AbstractText>A program including education and use of biphasic manual defibrillators in AED mode and selective use of AEDs improved survival to discharge in hospitalized patients suffering from cardiopulmonary arrest.</AbstractText> |
1,416 | Severe frequent ventricular ectopy after exercise as a predictor of death in patients with heart failure. | The study was done to determine the prognostic importance of frequent ventricular ectopy in recovery after exercise among patients with systolic heart failure (HF).</AbstractText>Although ventricular ectopy during recovery after exercise predicts death in patients without HF, its prognostic importance in patients with significant ventricular dysfunction is unknown.</AbstractText>Systematic electrocardiographic data during rest, exercise, and recovery were gathered on 2,123 consecutive patients with left ventricular systolic ejection fraction <or=35% who were referred for symptom-limited metabolic treadmill exercise testing. Severe ventricular ectopy was defined as the presence of ventricular triplets, sustained or nonsustained ventricular tachycardia, ventricular flutter, polymorphic ventricular tachycardia, or ventricular fibrillation. The primary end point was all-cause mortality, with censoring for interval cardiac transplantation.</AbstractText>Of 2,123 patients, 140 (7%) had severe ventricular ectopy during recovery. There were 530 deaths (median follow-up among survivors 2.9 years). Severe ventricular ectopy during recovery was associated with an increased risk of death (three-year death rates 37% vs. 22%, hazard ratio [HR] 1.76; 95% confidence interval [CI] 1.32 to 2.34, p < 0.0001). After adjustment for ventricular ectopy at rest and during exercise, peak oxygen uptake, and other potential confounders, severe ventricular ectopy during recovery remained predictive of death (adjusted HR 1.48; 95% CI 1.10 to 1.97; p = 0.0089), whereas ventricular ectopy during exercise was not predictive of death in this cohort.</AbstractText>Severe ventricular ectopy during recovery after exercise is predictive of increased mortality in patients with severe HF and can be used as a prognostic indicator of adverse outcomes in HF cohorts.</AbstractText> |
1,417 | Effect of mitral valve repair/replacement surgery on atrial arrhythmia behavior. | Few data have been published on the effects of mitral valve surgery on atrial rhythm. The study aims were to determine the effects of surgery on: (i) persistence of atrial fibrillation (AF); (ii) measures of left atrial and ventricular dimensions; and (iii) ECG P-wave duration.</AbstractText>A retrospective case-note review of 92 patients with chronic mitral regurgitation was undertaken. Variables determined included prevalence and duration of AF; incidence of new-onset or persistence of AF after surgery; rhythm changes in relation to age, gender, left atrial and ventricular dimensions and function, anti-arrhythmic drug usage and ECG P-wave duration in sinus rhythm prior to surgery.</AbstractText>Only 4/47 (8.5%) patients with any history of AF before surgery were in sinus rhythm at six months after surgery. All 28 patients with persistent AF for >12 months and 41/45 (91%) in sinus rhythm before surgery retained these rhythms after surgery. The left atrial dimension was decreased after surgery, in the whole group (51.3 +/- 9.0 versus 48.4 +/- 9.5 mm; p = 0.011) and in the subgroup in sinus rhythm, but not in the subgroup in AF. The left ventricular end-diastolic dimension decreased in the group as a whole (60.6 +/- 6.2 versus 53.0 +/- 8.7 mm; p = 0.0001) and in both subgroups after surgery. In 24 patients with 12- lead ECGs in sinus rhythm before and three months after surgery, P-wave duration remained unchanged. However, this measure decreased in the 18 patients in sinus rhythm consistently, but increased in the six patients continuing to have paroxysmal AF after surgery.</AbstractText>Mitral valve surgery alone restored sinus rhythm in only 8.5% of patients with any previous history of AF. Concomitant anti-arrhythmic procedures should be considered for all patients with AF who undergo mitral valve surgery.</AbstractText> |
1,418 | Risk factors and survival after aortic valve replacement in octogenarians. | The study aim was to determine if aortic valve replacement in octogenarians is still rewarding.</AbstractText>Between 1986 and 2000, 500 patients received a Carpentier-Edwards pericardial valve in the aortic position. Of these patients, 348 also underwent coronary artery bypass grafting (CABG). Sixty patients were aged > or =80 years. A retrospective follow up totaled 2,022 patient-years. A Cox multivariate regression analysis included 17 preoperative potential risk factors: age >80 years; gender; carcinoma; chronic obstructive pulmonary disease; renal failure; stroke; arterial hypertension; carotid artery disease; myocardial infarction; coronary artery disease; conduction defects; atrial fibrillation; medically treated endocarditis; severity of symptoms; urgent operation; left ventricular function; and need for digitalis.</AbstractText>For hospital mortality, independent predictors were urgent surgery (Risk Ratio 10.2, 95% CI 2.5-42.0, p = 0.001); age over 80 (RR 4.5, CI 1.3-14.9; p = 0.015); need for digitalis (RR 3.8, CI 1.3-10.6, p = 0.010); male gender (RR 3.7, CI 1.1-12.4; p = 0.035); and myocardial infarction (RR 3.1, CI 1.0-9.4, p = 0.051). For long-term mortality, independent predictors. were urgent surgery (RR 4.5, CI 1.6-12.6; p = 0.004), age >80 (RR 2.5, CI 1.4-4.5, p = 0.002); myocardial infarction (RR 2.1, CI 1.3-3.4; p = 0.003); carcinoma (RR 2.0; CI 1.1-3.7; p = 0.021); and digitalis use (RR 1.8; CI 1.2-2.7; p = 0.004). Univariate analysis revealed that age >80 years (38.6% versus 77.0%), need for urgent operation (0% versus 75.1%), need for digitalis (69.4% versus 76.3%) and myocardial infarction (57.1% versus 76.4%) had a significant effect on five-year survival.</AbstractText>For hospital mortality and long-term mortality, a need for urgent surgery was the most determining factor. Age >80 years was the second most important factor, but previous myocardial infarction and need for digitalis were almost equally important. Aortic valve replacement in octogenarians is still rewarding, as five-year survival is 38.6%. Thus, surgery in these patients should not be postponed.</AbstractText> |
1,419 | The impact of arrhythmias in acute heart failure. | Arrhythmias are common in chronic heart failure and affect outcomes. The incidence and significance of new arrhythmias in acute heart failure, however, are largely unknown.</AbstractText>The Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations study randomized 949 patients with decompensated heart failure to receive intravenous milrinone or placebo. In the study, patients were divided into 2 groups based on the occurrence of a new arrhythmic event during their index hospitalization and analyzed for outcome. There were 59 new arrhythmic events occurring in 6% of the population. Of these, 49% were atrial fibrillation/flutter. The primary endpoint of days hospitalized for cardiovascular causes within 60 days after randomization was 30.9+/-22.7 for those in the arrhythmia group and 11.3+/-12.7 days for those with no arrhythmias (P=.0001). Mortality during index hospitalization was 26% in the arrhythmia group and 1.8% in the no arrhythmia group (P=.001). Death or hospitalization at 60 days was also worse in the arrhythmia group (35 versus 8.2%, P=.0001; 57 versus 34%, P=.001, respectively). Cox proportional hazard analysis identified new arrhythmias as an independent risk factor for the primary endpoint and death at 60 days.</AbstractText>New arrhythmia during an exacerbation of heart failure identifies a high-risk group with higher intrahospital and 60-day morbidity and mortality.</AbstractText> |
1,420 | Control of heart rate versus rhythm in rheumatic atrial fibrillation: a randomized study. | Patients with rheumatic heart disease with atrial fibrillation incur significant morbidity and mortality. Which approach, ventricular rate control or maintenance of sinus rhythm, in this setting might be superior is not known. The role of amiodarone in this patient population for maintaining sinus rhythm has not been evaluated.</AbstractText>We prospectively studied 144 patients with chronic rheumatic atrial fibrillation in a double-blind protocol in which rhythm control (group I), comprising 48 patients each with amiodarone (group Ia) and placebo (group Ib), were compared with each other and with patients in a ventricular rate control group (group II) in which the effects by diltiazem were determined (n = 48, open-label). Direct current cardioversion was attempted in group I. The mean age of the study population was 38.6 +/- 10.3 years, left atrial size, 4.7 +/- 0.6 cm; atrial fibrillation duration, 6.1 +/- 5.4 years; and 72.9% had valvular interventions performed. At 1 year, 45 patients with sinus rhythm in group I compared with 48 in group II demonstrated an increase in exercise time (2.6 +/- 1.9 vs. 0.6 +/- 2.5 min, P =.001), improvement in New York Heart Association class of 1 or more (P =.002), and improvement in the quality-of-life score of one or greater (P = 0.01) with no difference in hospitalizations, systemic bleeds, or thromboembolism. Five patients died in group II; none died in group I (P =.02). In group I, 73 of 87 (83.9%) patients converted to sinus rhythm and 45 of 86 (52.3%) patients maintained the rhythm at 1 year. Conversion rates were 38 of 43 (88.4%) with amiodarone versus 34 of 44 (77.3%) with placebo (P =.49); the corresponding rate for maintaining sinus rhythm was 29 of 42 (69.1%) versus 16 of 44 (36.4%) (P =.008). A larger number of electrical cardioversions were required in the placebo group (2.1 vs. 1.4, P =.011).</AbstractText>Maintenance of sinus rhythm is superior to ventricular rate control in patients with rheumatic atrial fibrillation with respect to effects on exercise capacity, quality of life, morbidity, and possibly mortality. Sinus rhythm could be restored in most patients, and amiodarone was superior to placebo in the restoration and maintenance of sinus rhythm.</AbstractText> |
1,421 | A rationale for the use of anticoagulation in heart failure management. | Heart failure is a major public health concern for which treatment options have continued to evolve. While specific therapies such as beta blockers and angiotensin converting enzyme inhibitors have been shown to decrease hospitalizations and improve survival, the benefits of anticoagulation are less clear. Clinical guidelines detailing the appropriate use of anticoagulation for the management of atrial fibrillation and embolic stroke exist, but similar recommendations for their use in isolated cardiac dysfunction are lacking. Epidemiologic studies have documented increased risk of thrombus formation and stroke occurrence in patients with cardiomyopathy that is inversely related to ejection fraction. However, it remains at the clinician's discretion to determine at what degree of left ventricular dysfunction the potential benefits of stroke reduction outweigh the risks of undesirable bleeding with anticoagulation. This paper summarizes the pathophysiology of thrombus formation in heart failure patients; reviews previous studies and current recommendations for anticoagulation; provides a clinical rationale for anticoagulation when conclusive data are lacking; and discusses ongoing clinical trials designed to clarify these issues. |
1,422 | Mutational screening of SCN5A linked disorders in Polish patients and their family members. | Mutations in SCN5A lead to a broad spectrum of phenotypes, including the Long QT syndrome, Brugada syndrome, Idiopathic ventricular fibrillation (IVF), Sudden infant death syndrome (SIDS) (probably regarded as a form of LQT3), Sudden unexplained nocturnal death syndrome (SUNDS) and isolated progressive cardiac conduction defect (PCCD) (Lev-Lenegre disease). Brugada Syndrome (BS) is a form of idiopathic ventricular fibrillation characterized by the right bundle-branch block pattern and ST elevation (STE) in the right precordial leads of the ECG. Mutations of the cardiac sodium channel SCN5A cause the disorder, and an implantable cardioverter-defibrillator is often recommended for affected individuals. In this study sequences of the coding region of the SCN5A gene were analysed in patients with the LQT3, Brugada Syndrome and other arrythmogenic disorders. Different mSSCP patterns are described with no disease-related SSCP conformers in any sample. Direct sequencing of the SCN5A gene confirmed the absence of mutations. This suggests that the analysed region of the SCN5A gene is not commonly involved in the pathogenesis of the Brugada Syndrome and associated disorders. |
1,423 | Dynamic and not static change in ventricular repolarization is a substrate of ventricular arrhythmia on chronic ischemic myocardium. | The restitution mechanism has been the focus of attention as the possible mechanism behind ventricular fibrillation (VF). However, its contribution in chronic ischemic heart has not been established.</AbstractText>We investigated chronic ischemic dogs with occlusion of left anterior descending artery. Sixty unipolar electrograms were simultaneously recorded from an entire cardiac surface. Activation-recovery intervals (ARIs) and QRST deflection area (AQRST) were measured during constant atrial pacing. The ischemic dogs were divided into two groups, five dogs in VF(+) group or seven dogs in VF(-) group, according to VF occurrence by programmed electrical stimulation.</AbstractText>When investigating ARI dispersions on an epicardium, there was no difference between VF(+) and VF(-) groups. The relationship between ARIs and diastolic intervals was quantified as an electrical restitution curve. The slopes of the ARI restitution curve for the anterior left ventricle in VF(+) dogs were significantly steeper than those of VF(-) dogs. The amplitude of AQRST alternans were significantly greater in VF(+) dogs than VF(-) dogs.</AbstractText>Combined observation of steep restitution slopes and increased electrical alternans supported the restitution mechanism as being involved in the arrhythmia. Dynamic restitution properties and not static single-beat ARI dispersion may play an important role in the VF arrhythmia in the chronic ischemic heart.</AbstractText> |
1,424 | Enhanced specificity of a dual chamber ICD arrhythmia detection algorithm by rate stability criteria. | Inappropriate therapy remains an important limitation of implantable cardioverter defibrillators (ICD). PARAD+ was developed to increase the specificity conferred by the original PARAD detection algorithm in the detection of atrial fibrillation (AF). To compare the performances of the two different algorithms, we retrospectively analyzed all spontaneous and sustained episodes of AF and ventricular tachycardia (VT) documented by state-of-the-art ICDs programmed with PARAD or PARAD+ at the physicians' discretion. The results were stratified according to tachycardia rates <150 versus > or =150 beats/min. The study included 329 men and 48 women (64 +/- 10 years of age). PARAD was programmed in 263, and PARAD+ in 84 devices. During a mean follow-up of 11 +/- 3 months, 1,019 VT and 315 AF episodes were documented among 338 devices. For tachycardias with ventricular rates <150 beats/min, the sensitivity of PARAD versus PARAD+ was 96% versus 99% (NS), specificity 80% versus 93% (P < 0.002), positive predictive value (PPV) 94% versus 91% (NS), and negative predictive value (NPV) 86% versus 99% (P < 0.0001). In contrast, in the fast VT zone, the specificity and PPV of PARAD (95% versus 84% and 100% versus 96%) were higher than those of PARAD+ (NS, P < 0.001). Among 23 AF episodes treated in 16 patients, 3 episodes triggered an inappropriate shock in 3 patients, all in the PARAD population. PARAD+ significantly increased the ICD algorithm diagnostic specificity and NPV for AF in the slow VT zone without compromising patient safety. |
1,425 | Immediate and 1-year survival of out-of-hospital cardiac arrest victims in southern New Jersey: 1995-2000. | Most studies report the out-of-hospital cardiac arrest (OHCA) survival to hospital discharge. One-year survival and neurological outcomes in southern New Jersey in 1996-2000 were analyzed using a retrospective data review. There were 1,597 cases of OHCA. Initial survival ranged between 15% in 2000 and 19% in 1997. Survival to hospital discharge, taken as a percent of the initial survivors, decreased from 44% in 1997 to 22% in 2000. In relation to all OHCA victims, survival to discharge decreased from 7.2% to 2.4%, respectively. On discharge from the hospital 19-50% of people had the diagnosis of anoxic brain damage. In ventricular fibrillation, survival to discharge was 41%, 46.7%, 40.7%, 37.5%, and 17.4%, respectively, from 1996 to 2000. The response time increased from 6.6 to 8.1 minutes. Correlation coefficient between in-hospital survival and response time was -0.73. The percent of people discharged with neurological damage increased from 38% to 50%. Initial survival was 29.2% in shockable and 7.5% in nonshockable rhythm (P < 0.001). Survival to discharge was 11.3% versus 1.6%, and survival to 1 year was 9.6% versus 0.7%, respectively (P < 0.001 for all). Overall, the neurologically favorable 1-year survival rate was 2.3% of all OHCA victims. One-year survival of OHCA victims without neurological deficits is low. In southern New Jersey the survival rate did not improve over the 5-year study. Not only initial (prehospital) mortality, but also "delayed" (in-hospital mortality) increases with increase of response time. |
1,426 | Mortality analysis in patients with atrial fibrillation and implantable permanent pacemaker after ablation of the atrioventricular node. | Atrial fibrillation is associated with excess mortality. This analysis was performed to determine the magnitude of the excess mortality risk.</AbstractText>Life table analysis of a published study of 350 patients undergoing radiofrequency ablation of the atrioventricular node and permanent pacemaker implantation for symptomatic paroxysmal or chronic atrial fibrillation. A substantial proportion of subjects had evidence of left ventricular dysfunction.</AbstractText>In this cohort, compared to expected population mortality, the relative mortality ratio was 234% and the annual excess death rate was 46 deaths/1000.</AbstractText> |
1,427 | Cardiac function-related gene expression profiles in human atrial myocytes. | To obtain insights into the molecular pathogenesis of heart failure in humans, we have analyzed the expression profiles of>12,000 genes in a total of 17 human specimens of right atrial myocytes. From this large data set, we here tried to identify gene clusters, expression level of which is correlated precisely with clinical parameter values of cardiac function. We could reveal that cardiac myocytes with normal sinus rhythm were clearly differentiated, in the point of view of gene expression, from those with atrial fibrillation. Further, an expression profile-based prediction of arrhythmia by a newly developed "weighted-distance method" could efficiently diagnose our samples. We could even construct calculation formulae for the values of left ventricular ejection fraction based on the expression level of selected genes. To our best knowledge, this is the first report to indicate that pumping ability of heart can be predicted by any measures of atrium. |
1,428 | Phase 2 reentry as a trigger to initiate ventricular fibrillation during early acute myocardial ischemia. | Phase 2 reentry caused by heterogeneous loss of the transient outward potassium current (I(to))-mediated epicardial action potential (AP) dome can produce a closely coupled R-on-T extrasystole leading to ventricular fibrillation (VF) under conditions of ST-segment elevation unrelated to ischemia. The present study examined the role of phase 2 reentry in the initiation of VF during early myocardial ischemia.</AbstractText>Regional myocardial ischemia was produced in an isolated, arterially perfused canine right ventricular wedge preparation. Transmembrane APs from 2 epicardial sites at each side of the ischemic border were simultaneously recorded together with measurements of extracellular potassium concentration ([K+]o) and a transmural ECG. Loss of the I(to)-mediated epicardial AP dome in the ischemic zone but not in the perfused tissue resulted in phase 2 reentry and associated R-on-T extrasystoles capable of initiating VF in 7 of 15 preparations during the first 3 to 9 minutes of myocardial ischemia, with marked ST-segment elevation and [K+]o accumulation. The I(to) and phase 1 magnitude of epicardium contributed importantly to the onset of VF. Phase 1 magnitude and I(to) density at +30 mV in the group with phase 2 reentry-related R-on-T extrasystoles were 32.2+/-1.3 mV and 30.3+/-0.5 pA/pF (n=7), respectively, significantly greater than those (24.0+/-1.8 mV and 23.2+/-1.0 pA/pF) in the group without the extrasystoles (n=8, P<0.01).</AbstractText>Acute regional myocardial ischemia results in markedly heterogeneous loss of I(to)-mediated epicardial AP domes across the ischemic border, leading to phase 2 reentry. Phase 2 reentry can in turn produce an R-on-T extrasystole capable of initiating VF.</AbstractText> |
1,429 | Rate control vs rhythm control in patients with nonvalvular persistent atrial fibrillation: the results of the Polish How to Treat Chronic Atrial Fibrillation (HOT CAFE) Study. | The relative risks and benefits of strategies of rate control vs rhythm control in patients with atrial fibrillation (AF) remain to be fully explored.</AbstractText>The How to Treat Chronic Atrial Fibrillation (HOT CAFE) Polish trial was designed to evaluate in a randomized, multicenter, and prospective manner the feasibility and long-term outcomes of rate control vs rhythm control strategies in patients with persistent AF.</AbstractText>Our study population comprised 205 patients (134 men and 71 women; mean [+/- SD] age, 60.8 +/- 11.2 years) with a mean AF duration of 273.7 +/- 112.4 days. The mean observation period was 1.7 +/- 0.4 years. One hundred one patients were randomly assigned to the rate control group and received rate-slowing therapy guided by repeated 24-h Holter monitoring. Direct current cardioversion and atrioventricular junctional ablation with pacemaker placement were alternative nonpharmacologic strategies for patients with tachycardia that was resistant to medical therapy. One hundred four patients were randomized to sinus rhythm restoration and maintenance using serial cardioversion supported by a predefined stepwise antiarrhythmic drug regimen (ie, disopyramide, propafenone, sotalol, and amiodarone). In both groups, thromboembolic prophylaxis followed current guidelines.</AbstractText>At the end of follow-up, 63.5% of patients in the rhythm control arm remained in sinus rhythm. No significant differences in the composite end point (ie, all-cause mortality, number of thromboembolic events, or major bleeding) were found between the rate control group and the rhythm control group (odds ratio, 1.98; 95% confidence interval, 0.28 to 22.3; p > 0.71). The incidence of hospital admissions was much lower in the rate control arm (12% vs 74%, respectively; p < 0.001). New York Heart Association functional class improved in both study groups, while mean exercise tolerance, as measured by the maximal treadmill workload, improved only in the rhythm control group (5.2 +/- 5.1 vs 7.6 +/- 3.3 metabolic equivalents, respectively; p < 0.001). The rhythm control strategy led to an increased mean left ventricular fractional shortening (29 +/- 7% vs 31 +/- 7%, respectively; p < 0.01). One episode of pulmonary embolism occurred in the rate control group despite oral anticoagulation therapy, while three patients in the rhythm control arm of the study experienced ischemic strokes (not significant).</AbstractText>The Polish HOT CAFE study revealed no significant differences in major end points between the rate control group and the rhythm control group.</AbstractText> |
1,430 | Early assessment of heart rate variability is predictive of in-hospital death and major complications after acute myocardial infarction. | Depressed heart rate variability at acute myocardial infarction discharge is associated with poor long-term prognosis. However, its early (<48 h) predictive value has not been extensively investigated. Aim of this Multicenter Italian Study was to investigate, during acute myocardial infarction, in-hospital prognostic value of heart rate variability and its short-term evolution.</AbstractText>Twenty-four hour ECG monitoring was prospectively obtained on admission in 413 patients with new-onset acute myocardial infarction and repeated in 349 at discharge. Heart rate variability statistical and frequency domain indices, peak creatine kinase, echocardiographic wall motion score index and risk factors were obtained. The occurrence of cardiac death and resuscitated ventricular fibrillation were the primary end-points; cardiogenic shock, ventricular tachycardia, post-infarction angina and heart failure the secondary end-points.</AbstractText>At admission, a marked reduction in heart rate variability indices was evident. Nine patients died during hospitalization and 13 were resuscitated from ventricular fibrillation. Secondary endpoints occurred in other 91 patients. At univariate analysis, low frequencies (LF), mean time interval between consecutive heart beats (RR), wall motion score index and family history of ischemic heart disease were predictive of combined primary and secondary end-points. At multivariate analysis, only LF and family history were predictive with a relative risk of 2.01 and 1.84, respectively (P<0.003). In survivors, heart rate variability indices significantly increased during hospitalization, still remaining below reference values.</AbstractText>A depressed heart rate variability was present in the early phase of infarction and improved at discharge. LF power was an independent predictor of the combined unfavorable short-term events.</AbstractText> |
1,431 | P wave dispersion and left atrial appendage function for predicting recurrence after conversion of atrial fibrillation and relation of p wave dispersion to appendage function. | We investigated P wave dispersion and left atrial appendage (LAA) function for predicting atrial fibrillation (AF) relapse, and the relationship between P wave dispersion and LAA function.</AbstractText>Sixty-four consecutive patients with AF lasting </=3 months were evaluated to predict the recurrence after successful cardioversion. P wave duration and dispersion were measured in a 12-lead electrocardiograph (ECG). The size and function of the left atrium (LA) and LAA were assessed by transthoracic and transesophageal echocardiography.</AbstractText>After 6 months, 28 patients experienced recurrent AF and 36 remained in sinus rhythm. There was no difference between patients with and without recurrence in gender, age, underlying heart disease, AF patterns, left ventricular function, and maximum LAA area. AF duration >/=5 days, LA size >/=45 mm, maximum P wave duration >/=112 ms, P wave dispersion >/=47 ms, spontaneous echo contrast, minimum LAA area >/=166 mm(2), and LAA emptying velocity <36 cm/sec were univariate predictors of recurrence (each P < 0.05). By multivariate analysis, LA size (P = 0.02), P wave dispersion (P < 0.001), and LAA emptying flow (P = 0.01) identified patients with recurrent AF. Their positive predictive values were 91, 97, and 72%, respectively.</AbstractText>The increased P wave dispersion in addition to the dilated LA and the depressed LAA emptying flow can identify patients at risk of recurrent AF after cardioversion.</AbstractText> |
1,432 | [Recovery from fatal ventricular fibrillation after immediate application of percutaneous cardiopulmonary support]. | We present a patient who recovered from refractory ventricular fibrillation after immediate application of percutaneous cardiopulmonary support (PCPS). On the postoperative day (POD) 3 after the Y-grafting surgery for abdominal aortic aneurysm, circulation collapsed due to sudden onset of ventricular fibrillation. Because ventricular fibrillation had persisted in spite of medical treatment and defibrillation, we established PCPS and his circulation recovered. Although an emergent coronary angiography revealed no new lesions, we performed an emergent percutaneous catheter intervention to deny the possibility that ischemic changes had contributed to the arrhythmia. Soon after percutaneous transluminal coronary angioplasty, we successfully weaned him from PCPS, and extubated his trachea on the POD 5 without any neurological deficits. On the POD 8, ventricular fibrillation occurred again and defibrillation was effective at this time. We suspected cardiac ischemia, prolonged QT interval, and electrical remodeling due to hypertrophic heart as possible causes of refractory ventricular fibrillation. Therefore, we performed percutaneous transluminal coronary angioplasty, terminated famotidine administration, maintained normal electrolytes level, started administration of beta-blocker, and implanted an cardioverter defibrillator. On the POD 16, he was discharged from the ICU with no neurological deficits. |
1,433 | [Successful management of a patient for cardiac surgery with difficulty in weaning from cardiopulmonary bypass by using both isosorbide dinitrate and olprinone hydrochloride]. | A 57-year-old man with mitral stenosis underwent mitral valve plasty under general anesthesia. He had a history of cerebral infarction. Although he was with atrial fibrillation, his left ventricular function was good. Preoperative coronary angiography revealed no significant coronary stenosis. Induction of anesthesia and the surgical procedure had been uneventful, but the patient had difficulty to wean the patient from cardiopulmonary bypass because of unexpected low cardiac output syndrome. O1-prinone hydrochloride, a newly developed phosphodiesterase III inhibitor, was initiated in addition to high doses of dopamine and dobutamine. This increased the amplitude of the electrocardiogram and caused ST elevation of the lead II. A full dose of isosorbide dinitrate was administered intravenously to differentiate coronary artery spasm from coronary air embolism. This drastically improved the ventricular function and mixed venous oxygen saturation, and weaning from CPB was finally accomplished. The heart showed hypercontraction and inotropes were tapered gradually without further cardiac events. Although there are various etiologies for low cardiac output syndrome after CPB, the possibility of myocardial ischemia must be the first consideration. Full pharmacological support must be tried before initiating a mechanical assist modality. Coronary dilators, nitrates in particular, and phosphodiesterase III inhibitors are promising agents in such cases. |
1,434 | Transthoracic echocardiography for precardioversion screening during atrial flutter/fibrillation in young patients. | Transthoracic echocardiography (TTE) is reliable for detection of thrombi in the left ventricle and right atrium, but not in the left atrial appendage. Therefore, transesophageal echocardiography (TEE) is routinely performed in adults prior to electric cardioversion for atrial flutter/fibrillation (AFF). Whether young survivors of congenital heart disease repair with AFF need routine TEE prior to electric cardioversion is unknown.</AbstractText>Electric cardioversion for AFF is safe in survivors of congenital heart disease repair/palliation if an intracardiac thrombus is not suspected on TTE imaging.</AbstractText>This study reports the outcome of patients in a pediatric tertiary care cardiac unit where electric cardioversion was performed if no intracardiac thrombus was suspected on TTE. We performed a retrospective chart review of all patients treated with electric cardioversion for AFF at Children's Hospital of Michigan during 1997-2002.</AbstractText>Of 35 patients who presented with 110 episodes of AFF requiring electric cardioversion during the study duration, 32 (age 3 months-49 years, median age 20.5 years, 104 AFF episodes) had previously undergone palliative surgery or repair of their congenital heart disease. Of these 32 patients, 18 were survivors of a Fontan palliation (for a single-ventricle variant) and the remaining 14 were survivors of other defects and repairs (septal defects, valve replacements, and tetralogy of Fallot). During 81% of the episodes, patients were receiving aspirin, warfarin, or heparin for anticoagulation at presentation. Transthoracic echocardiography was performed in 74 AFF episodes; of these, 10 TTE studies were suspicious for atrial thrombi. Transesophageal echocardiography confirmed the presence of a thrombus in 3 of these 10 patients. These patients received warfarin for 2 weeks and then underwent electric cardioversion. No thromboembolic events occurred immediately after or on follow-up in any patient.</AbstractText>These findings suggest that TTE may be an effective imaging tool for precardioversion screening in young patients with AFF.</AbstractText> |
1,435 | Left ventricular assist device (LVAD) enables survival during 7 h of sustained ventricular fibrillation. | We describe the case of a patient implanted with a DeBakey left ventricular assist device (LVAD) as bridge to transplant who survived 7 h of ventricular fibrillation. He was successfully converted into a stable sinus rhythm. |
1,436 | Efficacy of lower-energy biphasic shocks for transthoracic defibrillation: a follow-up clinical study. | This clinical study prospectively evaluated the first-shock defibrillation efficacy of 150-joule impedance-compensated, 200-microF biphasic truncated exponential (BTE) shocks in patients with electrically-induced ventricular fibrillation (VF), and compared it with a historical control group treated with 200-J monophasic damped sine (MDS) shocks.</AbstractText>Ventricular tachyarrhythmias were induced in patients undergoing electrophysiologic (EP) testing for ventricular arrhythmias or testing of an implantable cardioverter-defibrillator (ICD). A 150-J shock was delivered as the primary therapy to terminate induced arrhythmias in the EP group, and as a "rescue" shock when a single ICD shock failed to terminate the arrhythmias in the ICD group.</AbstractText>Ninety-six patients received study shocks. The preshock rhythm was classified as VF in 77 patients and as ventricular tachycardia (VT) in 19 patients. First-shock success rates for VF and VT were 75 out of 77 (97.4%) and 19 out of 19 (100%) for the 150-J BTE compared with the historical control rates of 61 out of 68 (89.7%) and 29 out of 31 (94%) for 200-J MDS. The first-shock success rate for VF treated with 150-J BTE was technically equivalent to that of 200-J MDS (p=0.001). The transthoracic impedance did not vary between groups, yet the peak current delivered by the 150-J BTE shock was about 50% lower.</AbstractText>This study demonstrated that 150-J shocks of this impedance-compensated, 200-microF BTE waveform provided very high efficacy for defibrillation of short duration, electrically-induced VF. These lower-energy biphasic shocks had a success rate equivalent to that of 200-J MDS shocks, and they provided this efficacy while exposing patients to much less current than the monophasic shocks.</AbstractText> |
1,437 | Effects of vasopressin on left anterior descending coronary artery blood flow during extremely low cardiac output. | Because of the possibility of vasopressin-mediated coronary vasospasm, this study was designed to assess effects of vasopressin compared to saline placebo on left anterior descending (LAD) coronary artery blood flow. Twelve anaesthetized domestic swine were prepared for LAD coronary artery blood flow measurement with ultrasonic flow probes, using cardiopulmonary by-pass adjusted to 10% of the prearrest cardiac output. This 10% value approximates that reported for cardiac output during conventional closed-chest CPR. After 4 min of untreated ventricular fibrillation, and 3 min of cardiopulmonary by-pass blood flow, 12 pigs were randomly assigned to receive intravenously, every 5 min, either vasopressin (0.4, 0.4, and 0.8 U/kg; n = 6) or saline placebo (n = 6). The mean +/- S.D. LAD coronary artery blood flow in the vasopressin and placebo pigs was comparable before cardiac arrest, and during cardiopulmonary by-pass low flow; but increased significantly (P < 0.05) 90 s after each of three vasopressin injections compared to placebo (78 +/- 1 versus 42 +/- 2 ml/min; 62 +/- 2 versus 36 +/- 1 ml/min; and 54 +/- 1 versus 27 +/- 1 ml/min), respectively. Coronary vascular resistance decreased significantly (P < 0.05 ) 90 s after each of three vasopressin and placebo injections. In this model, repeated bolus administration of vasopressin, given during simulated extremely low cardiac output improved LAD coronary artery blood flow to prearrest levels without affecting coronary vascular resistance.</AbstractText>during extremely low blood flow using cardiopulmonary by-pass, vasopressin improves LAD coronary artery blood flow without affecting coronary vascular resistance.</AbstractText> |
1,438 | Continuous intratracheal insufflation of oxygen improves the efficacy of mechanical chest compression-active decompression CPR. | The aim of the present study was to compare the efficacy of intratracheal continuous insufflation of oxygen (CIO) with intermittent positive pressure ventilation (IPPV) regarding gas exchange and haemodynamics during mechanical chest compression-active decompression cardiopulmonary resuscitation (mCPR) provided by the LUCAS device. Ventricular fibrillation (VF) was induced electrically and ventilation was discontinued in 16 pigs, mean body weight 23 kg (range 22-27 kg). They were randomized into two groups (CIO versus IPPV). After 8 min of VF, mCPR was started and run for 30 min in normothermia, after which defibrillation was attempted during on-going mCPR. Return of spontaneous circulation was obtained in eight of eight CIO pigs and in four of eight IPPV pigs. Arterial oxygen tension (P < 0.05) and coronary perfusion pressure (P < 0.01) were significantly higher in the CIO pigs. Arterial CO(2)-tension was subnormal in both groups and significantly (P < 0.05) lower in the IPPV-pigs (around 4.5 versus 3.0 kPa). The intratracheal pressure differed significantly (P < 0.001) between the two groups. It was negative in each decompression phase in the IPPV pigs in spite of 6 mmHg of PEEP. The CIO pigs had a positive intratracheal pressure during the whole cycle of mCPR, with a minimum pressure of 8 mmHg during each decompression phase. To conclude, mCPR combined with CIO gave adequate ventilation and significantly better oxygenation and coronary perfusion pressure than mCPR combined with IPPV. |
1,439 | Assessment of upgrading to biventricular pacing in patients with right ventricular pacing and congestive heart failure after atrioventricular junctional ablation for chronic atrial fibrillation. | Effects of cardiac resynchronization therapy (CRT) in patients with right ventricular pacing and congestive heart failure (CHF) have only been reported in limited series. CRT in patients with atrial fibrillation remains controversial. Patients with AV junctional ablation offer a unique opportunity to study the effects of CRT in patients with right ventricular pacing combined with atrial fibrillation. The aims of the present study were to evaluate the effects of upgrading to biventricular pacing patients with CHF, permanent atrial fibrillation, and prior ablation of the atrioventricular (AV) junction followed by conventional right ventricular pacing.</AbstractText>We studied 16 consecutive patients with permanent atrial fibrillation treated by AV junctional ablation. After a mean follow-up of 20+/-19 months (6 weeks to 5 years) they were successfully upgraded to biventricular pacing for severe CHF. Parameters were prospectively evaluated at baseline and at 6 months. The 14 surviving patients at 6 months demonstrated significant improvement (P<0.02) in New York Heart Association class but the exercise test parameters remained unchanged. Cardiothoracic ratio decreased by 5% (P=0.04), end-systolic diameter by 8% (P=0.001), end-diastolic diameter by 4% (P=0.08), systolic pulmonary artery pressure by 17% (P<0.0001) and mitral regurgitation area by 40% (P<0.05). Ejection fraction increased by 17% (P=0.11) and fractional shortening by 24% (P=0.01).</AbstractText>CRT improves left ventricular performance and functional status in patients with permanent atrial fibrillation and prior remote right ventricular pacing.</AbstractText> |
1,440 | The role of implantable cardioverter defibrillator for primary vs secondary prevention of sudden death in patients with idiopathic dilated cardiomyopathy. | To analyse the characteristics and outcome of patients with idiopathic dilated cardiomyopathy (DC) considered at high risk of sudden death (SD) and treated with implantable cardioverter defibrillators (ICD) for primary prevention (Group A) in comparison with patients treated with ICDs because of previous sustained ventricular tachyarrhythmias or syncope (Group B).</AbstractText>Group A consisted of 27 patients with at least two of the following criteria: left ventricular end-diastolic diameter (LVEDD) > or =70 mm (74%), LV ejection fraction (LVEF) < or =30% (78%), non-sustained ventricular tachycardia (VT) (56%), long history of disease (> or =48 months since diagnosis, 85%) and family history of SD (11%). Group B consisted of 27 patients treated with ICDs because of sustained VT/fibrillation (n=18) or syncope (n=9).</AbstractText>NYHA class, LVEF, LVEDD and amiodarone treatment were similar in the two groups. Patients in group A were younger (46+/-15 vs 59+/-17 years, P=0.0008), were more often treated with beta-blockers (89% vs 62%; P=0.02) and had a longer interval since diagnosis (86+/-60 vs 40+/-50 months; P=0.004). Twelve month rates of appropriate intervention (AI) were 41% in Group A and 57% in group B (P NS). In group A, after a mean follow-up of 21+/-14 months, patients showing the combination of LVEF < or =30% and LVEDD > or =70 mm had the highest frequency of AI (76% vs 10%, P=0.005). In group B, after a mean follow-up of 33+/-23 months, 78% of patients with syncope had AI. Total and sudden deaths were 11% and 4% in group A and 19% and 4% in group B (P NS).</AbstractText>Patients with idiopathic DC treated with ICD for primary prevention because they were considered at high risk of SD according to clinical criteria showed a high rate of AI, similar to that of patients treated for secondary prevention. The highest rate of AI was seen in patients with both severe dysfunction and dilatation and in those with previous syncope.</AbstractText> |
1,441 | Evaluation of KCB-328, a new IKr blocking antiarrhythmic agent in pacing induced canine atrial fibrillation. | KCB-328 is a new potassium channel blocker, which prolongs action potential duration with exhibition of minimal reverse use dependence. We tested the efficacy and proarrhythmic potential of KCB-328, dofetilide and propafenone in the pacing induced canine model of atrial fibrillation (AF).</AbstractText>Mongrel dogs in complete heart block were paced for 1-6 weeks to produce AF, and given KCB-328 or dofetilide. A subset then received propafenone 14+/-3 days after testing the first drug.</AbstractText>KCB-328 prolonged right and left atrial (RA and LA) activation times and AF cycle length (CL), terminating AF in 3 of 6 dogs. RA effective refractory period (ERP) and ventricular ERP and QT interval were prolonged. Dofetilide terminated AF in 1/6 dogs, and increased AF CL and ventricular ERP and QT interval. Dofetilide's reverse use dependency on the QT interval was greater than KCB-328. Propafenone prolonged RA and LA activation times and AF CL and terminated AF in 8 of 9 dogs. One death occurred with dofetilide, none with KCB-328 or propafenone.</AbstractText>The spectrum of effect of the three drugs differed significantly: propafenone showed the greatest success in AF termination, and both propafenone and KCB-328 appeared less proarrhythmic than dofetilide in this model.</AbstractText> |
1,442 | Atrial pacing for prevention of atrial fibrillation: assessment of simultaneously implemented algorithms.<Pagination><StartPage>371</StartPage><EndPage>379</EndPage><MedlinePgn>371-9</MedlinePgn></Pagination><Abstract><AbstractText Label="AIMS" NlmCategory="OBJECTIVE">Several preliminary studies indicated that right atrial pacing could prevent atrial tachyarrhythmias (ATA). We sought to compare the safety and the efficacy of atrial-based pacing supplemented by dedicated combined algorithms with conventional atrial pacing in the prevention of ATA.</AbstractText><AbstractText Label="METHODS" NlmCategory="METHODS">Fifty-five patients with a history of recurrent paroxysmal ATA implanted with a dual-chamber pacemaker were studied during two randomized cross-over pacing periods (conventional DDD and DDD with ATA prevention algorithms) of 6 months duration. The primary endpoint was the burden of ATA episodes recorded by the device mode switch algorithm.</AbstractText><AbstractText Label="RESULTS" NlmCategory="RESULTS">The cross-over analysis did not demonstrate any significant difference between the two pacing modes: 254+/-533 h of ATA during the control period versus 238+/-518 h during the ATA prevention period. Analysis of a subgroup of patients found that those with the lower percentage of ventricular pacing benefited from ATA prevention algorithms (120+/-182 h versus 225+/-350 h during the control period; P < 0.04).</AbstractText><AbstractText Label="CONCLUSION" NlmCategory="CONCLUSIONS">When compared with DDD pacing at 70 bpm, ATA prevention algorithms have not demonstrated significant efficacy. However, a subgroup of patients with preserved native AV conduction (low percentage of ventricular pacing) responded to ATA prevention algorithms.</AbstractText></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Blanc</LastName><ForeName>Jean-Jacques</ForeName><Initials>JJ</Initials><AffiliationInfo><Affiliation>Cardiology Department, Brest University Hospital, Brest, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>De Roy</LastName><ForeName>Luc</ForeName><Initials>L</Initials></Author><Author ValidYN="Y"><LastName>Mansourati</LastName><ForeName>Jacques</ForeName><Initials>J</Initials></Author><Author ValidYN="Y"><LastName>Poezevara</LastName><ForeName>Yann</ForeName><Initials>Y</Initials></Author><Author ValidYN="Y"><LastName>Marcon</LastName><ForeName>Jean-Louis</ForeName><Initials>JL</Initials></Author><Author ValidYN="Y"><LastName>Schoels</LastName><ForeName>Wolfgang</ForeName><Initials>W</Initials></Author><Author ValidYN="Y"><LastName>Hidden-Lucet</LastName><ForeName>Françoise</ForeName><Initials>F</Initials></Author><Author ValidYN="Y"><LastName>Barnay</LastName><ForeName>Claude</ForeName><Initials>C</Initials></Author><Author ValidYN="Y"><CollectiveName>PIPAF Investigators</CollectiveName></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D016430">Clinical Trial</PublicationType><PublicationType UI="D003160">Comparative Study</PublicationType><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D016448">Multicenter Study</PublicationType><PublicationType UI="D016449">Randomized Controlled Trial</PublicationType><PublicationType UI="D013485">Research Support, Non-U.S. Gov't</PublicationType></PublicationTypeList></Article><MedlineJournalInfo><Country>England</Country><MedlineTA>Europace</MedlineTA><NlmUniqueID>100883649</NlmUniqueID><ISSNLinking>1099-5129</ISSNLinking></MedlineJournalInfo><CitationSubset>IM</CitationSubset><CommentsCorrectionsList><CommentsCorrections RefType="CommentIn"><RefSource>Europace. 2004 Sep;6(5):380-3</RefSource><PMID Version="1">15294261</PMID></CommentsCorrections></CommentsCorrectionsList><MeshHeadingList><MeshHeading><DescriptorName UI="D000368" MajorTopicYN="N">Aged</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D000465" MajorTopicYN="Y">Algorithms</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D001919" MajorTopicYN="N">Bradycardia</DescriptorName><QualifierName UI="Q000628" MajorTopicYN="N">therapy</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D002304" MajorTopicYN="N">Cardiac Pacing, Artificial</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="Y">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D018592" MajorTopicYN="N">Cross-Over Studies</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005260" MajorTopicYN="N">Female</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005500" MajorTopicYN="N">Follow-Up Studies</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006325" MajorTopicYN="N">Heart Atria</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D008297" MajorTopicYN="N">Male</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D008875" MajorTopicYN="N">Middle Aged</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D011446" MajorTopicYN="N">Prospective Studies</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D055502" MajorTopicYN="N">Secondary Prevention</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D016037" MajorTopicYN="N">Single-Blind Method</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D013612" MajorTopicYN="N">Tachycardia, Ectopic Atrial</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading></MeshHeadingList></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="received"><Year>2003</Year><Month>12</Month><Day>19</Day></PubMedPubDate><PubMedPubDate PubStatus="accepted"><Year>2004</Year><Month>5</Month><Day>9</Day></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2004</Year><Month>8</Month><Day>6</Day><Hour>5</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2005</Year><Month>1</Month><Day>28</Day><Hour>9</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="entrez"><Year>2004</Year><Month>8</Month><Day>6</Day><Hour>5</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">15294260</ArticleId><ArticleId IdType="doi">10.1016/j.eupc.2004.05.002</ArticleId><ArticleId IdType="pii">S109951290400145X</ArticleId></ArticleIdList></PubmedData></PubmedArticle><PubmedArticle><MedlineCitation Status="MEDLINE" Owner="NLM"><PMID Version="1">15293498</PMID><DateCompleted><Year>2005</Year><Month>04</Month><Day>14</Day></DateCompleted><DateRevised><Year>2006</Year><Month>11</Month><Day>15</Day></DateRevised><Article PubModel="Print"><Journal><ISSN IssnType="Print">0025-8075</ISSN><JournalIssue CitedMedium="Print"><Issue>3</Issue><PubDate><Year>2004</Year><Season>May-Jun</Season></PubDate></JournalIssue><Title>Meditsinskaia tekhnika</Title><ISOAbbreviation>Med Tekh</ISOAbbreviation></Journal>[Comparison of the efficiency and noise-immunity of the algorithms detecting the shock cardiac rhythms]. | Comparative assessments of the efficiency and noise immunity of the algorithms detecting the shock cardiac rhythms (SCR) are described in the paper. It is suggested to use the rejection filter of ventricular fibrillation as the principle algorithm for the SCR detection in an automated external defibrillator. The use of the method combining the after-threshold interval and the method of spectral analysis is demonstrated to be preferable for a portable external defibrillator. |
1,443 | [Heart arrest: which reality and which training for the practitioner?]. | Sudden death related to out-of hospital cardiac arrest is an important cause of mortality, which is mainly caused by ventricular fibrillation, a potentially reversible condition. The prognosis of out-of-hospital cardiac arrest remains dismal despite well developed emergency medical services. Witnessed arrest, ventricular fibrillation as the initial arrhythmia, cardiopulmonary resuscitation and early defibrillation are systematically associated with better survival. Key interventions must therefore be enforced to improve survival from out-of-hospital cardiac, introducing the concept of a "chain of survivals". The aim of the present article, which is illustrated by local results, is to review this important public health issue, to emphasize the role of the general practitioner in the chain of survival, and to promote education and training of basic and advanced life support. |
1,444 | Acute thrombus formation in the left atrium after the termination of warfarin. | We report a case of acute thrombosis formation in the left atrium 3 days after the discontinuation of warfarin therapy prior to mitral valve replacement in a patient with mitral stenosis and atrial fibrillation. A 58-year-old Asian female patient was scheduled for mitral valve replacement for mitral stenosis. She had received warfarin therapy every day for 2 years. Warfarin therapy was discontinued 3 days before surgery. Using transesophageal echocardiography (TEE), we confirmed that there was no thromboembolism at the left atrium 10 days before surgery. No replacement anticoagulant therapy, such as heparin, was given after the discontinuation of warfarin. After the induction of anesthesia, a TEE probe was inserted through the esophagus to monitor left ventricular function. We found two thrombi (35 mm and 40 mm in diameter) in the left atrium. This case shows that discontinuation of warfarin therapy within a few days before operation carries a risk of thromboembolism formation. |
1,445 | Anesthetic management of a patient undergoing cardioverter defibrillator implantation: usefulness of transesophageal echocardiography and near infrared spectroscopy. | A case of a patient with sustained ventricular tachycardia (VT) undergoing implantable cardiovertor defibrillator (ICD) implantation, using transesophageal echocardiography (TEE) and near infrared spectroscopy (NIR) is described. A 67-year-old man with sustained VT associated with old myocardial infarction underwent ICD implantation. Anesthesia was induced with fentanyl and propofol and maintained with nitrous oxide, oxygen, sevoflurane, and fentanyl. Global hypokinesis of the left ventricle was observed in the short-axis view provided by TEE. Intraoperative systolic blood pressure was maintained between 100 and 120 mmHg, and cerebral oxygenated hemoglobin (HbO2) was between 63% and 65%. During periods of induced ventricular fibrillation, systolic blood pressure decreased to 60 mmHg, HbO2 decreased to 59%, and TEE revealed cardiac arrest. These changes were transient; HbO2 returned to baseline values immediately after the restoration of normal rhythm. TEE confirmed no remarkable change in cardiac function after defibrillation testing. TEE and NIR were found to be beneficial for the anesthetic management of a patient with sustained VT who was underdoing ICD implantation. |
1,446 | KB-R9032, newly developed Na(+)/H(+) exchange inhibitor, attenuates reperfusion-induced arrhythmias in isolated perfused rat heart. | This study was conducted to elucidate the effects of KB-R9032, a newly developed Na(+)-H(+) exchange inhibitor, on reperfusion-induced ventricular arrhythmia in the isolated perfused rat heart.</AbstractText>Male Wistar rat hearts ( n = 48; 12 for each group) were perfused with modified Krebs-Ringer's solution equilibrated with 5% carbon dioxide in oxygen by means of the Langendorff technique. An occluder was placed around the left anterior descending coronary artery (LAD). Heart rate, coronary flow, and ECG were monitored. Drug-free perfusate was used for 10 min before switching to a perfusate containing various concentrations of KB-R9032. The added concentrations of KB-R9032 varied in the range of 0 (control) to 1 x 10(-5) mol x l(-1). Each heart was subjected to regional ischemia (occlusion of LAD for 11 min) and to 3 min of reperfusion (release of the ligation).</AbstractText>In the control group, reperfusion-induced ventricular fibrillation (VF) occurred in 91.7%, and the duration was 158.2 +/- 14.4 s (mean +/- SEM); however, 1 x 10(-7), 1 x 10(-6), and 1 x 10(-5) mol x l(-1) KB-R9032 reduced the incidence of VF to 75.0%, 42.9%, and 6.7%, respectively ( P < 0.05 at 1 x 10(-5) mol x l(-1) of KB-R9032) and reduced the duration of VF to 64.8 +/- 22.1, 16.8 +/- 10.1, and 1.2 +/- 1.2 s, respectively ( P < 0.05 at 1 x 10(-6) and 1 x 10(-5) mol x l(-1) of KB-R9032).</AbstractText>It was shown in this study that the Na(+)/H(+) exchange inhibitor KB-R9032 suppresses reperfusion arrhythmias in the ischemia-reperfusion model of isolated rat heart.</AbstractText> |
1,447 | Can local ventricular fibrillation interval predict ventricular refractory period in human hearts? | Assessment of the spatial dispersion of ventricular refractory periods has become an important part of electrophysiological study in both experimental and clinical settings, because inhomogeneity of ventricular refractoriness is associated with an increased risk of life-threatening ventricular arrhythmias. Previous animal studies in dog and sheep have demonstrated that local ventricular fibrillation (VF) intervals measured from the heart surface correlate well with the ventricular effective refractory periods measured from the same ventricular sites. We hypothesise that local VF intervals may also predict the ventricular refractory periods in human hearts, hence, can be used to assess the spatial dispersion of refractoriness and to predict the risk of ventricular arrhythmias. |
1,448 | Flecainide versus ibutilide for immediate cardioversion of atrial fibrillation of recent onset. | This study compared the efficacy and safety of intravenous flecainide and ibutilide for immediate cardioversion of atrial fibrillation (AF).</AbstractText>We conducted a prospective, randomised trial, including 207 patients with AF of recent onset (< or = 48 h). Flecainide was given over 20 min at a dose of 2 mg/kg body weight (maximum 200 mg), ibutilide was infused at a dose of 1 mg (or 0.01 mg/kg if less than 60 kg) over 10 min, followed by a 10 min observation period and an identical second dose if AF did not convert to sinus rhythm (SR). Treatment was considered successful if SR occurred within 90 min of starting medication. The conversion rates were 56.4% in patients given flecainide and 50.0% in patients given ibutilide (P=0.34). Multivariate analysis revealed that a lower age for women independently increased the probability of conversion. None of the other variables, including left atrial size, left ventricular systolic function, presence of left ventricular hypertrophy, plasma levels of potassium or magnesium at baseline, or concomitant use of digoxin, beta-blocker, diltiazem or verapamil were predictors of conversion. The frequency of adverse events was comparable in the two treatment groups.</AbstractText>There was no significant difference in the cardioversion efficacy or in the risk of adverse events between flecainide and ibutilide in patients with AF of recent onset. In patients without contraindications to both medications, the physician's choice has to be governed by other factors.</AbstractText> |
1,449 | Arrhythmias of a sudden traumatic death. | A 73-year-old man was treated because of his paroxysmal palpitations became persistent. At the time of hospital admission atrial flutter was found. Antiarrhythmic drug treatment was unsuccessful therefore electrical cardioversion was indicated which restored his sinus rhythm. After one year of uneventful follow up Holter monitoring was indicated again. When the machine was hooked up sinus rhythm was observed. After 53 minutes a tram knocked down the patient, and he died immediately. During autopsy brain laceration, multiple cranial fractions, mediastinal hemorrhage were found. The Holter recording time was 66 minutes. Before the accident sinus rhythm was recorded. At the time of accident an electrical noise was found, followed by long sinus arrest, atrial fibrillation, nodal escape rhythm, sinus bradycardia, ventricular flutter, tachycardia, fibrillation and "dying heart" rhythm. According to our knowledge this is the first Holter monitoring observation during a sudden traumatic death. |
1,450 | Different features of ventricular arrhythmias and the RR-interval dynamics in atrial fibrillation related to the patient's clinical characteristics: an analysis using RR-interval plotting. | The clinical features of ventricular arrhythmia and RR-interval dynamics in AF-patients remain unresolved. We successively plotted points on an X-Y plain as (X, Y) = (RRn, RRn + 1) from the consecutive RR-intervals of Holter ECGs. Eighty of 175 AF-patients were thus diagnosed to have ventricular arrhythmia based on the different plotting patterns between ventricular premature contractions (VPCs) and aberrations. Different characteristics of the RR-interval dynamics before VPCs were observed such as fixed or variable coupling, and a regular or irregular RR-interval sequence. Malignant arrhythmias occurred more frequently in AF-patients with variable coupling VPCs and/or an irregular RR-interval sequence before VPCs than in those with the fixed coupling VPCs and/or the regular RR-interval sequence before VPCs. The RR-interval plotting method enabled us to distinguish different types of VPCs which were related to the clinical characteristics of the AF-patients. |
1,451 | Transmural dispersion of repolarization and ventricular tachyarrhythmias. | Myocardial transmural dispersion of repolarization (TDR) has been associated with reentrant arrhythmias in animal studies but a clinical association has not yet to been demonstrated. The present study examines the relationship between TDR and ventricular tachyarrhythmias in human subjects.</AbstractText>This study consisted of 65 patients with non-sustained ventricular tachycardia, sustained ventricular tachycardia, ventricular fibrillation or unexplained syncope with organic heart disease. The control group included 65 patients with paroxysmal supraventricular tachycardia. The 12 ECG was recorded at a recording rate of 100 mm/sec. The interval from the peak to the end of the T wave in the precordial (ECG), referred to as TpTe was assumed to be representative of TDR.</AbstractText>Patients were divided into three groups based on the ability to induce VT at the time of electrophysiologic study: VT inducible group (n=37), VT non-inducible group (n=25) and control group (n=65). V4 TpTe/ radical RR was significantly prolonged in the VT inducible group, as compared to the VT non-inducible group (n=25) and the control group (118.9 +/- 26.1 vs. 103.9 +/- 25.7, 104.1 +/- 22.6 ms, P<.05). Patients who develop VT spontaneously (n=13) during a mean follow-up period of 25 months, displayed significantly prolonged V3 TpTe/ radical RR, compared to patients who did not develop VT spontaneously or the control group (132.5 +/- 37.4 vs. 109.8 +/- 26.3, 107.1 +/- 24.1 ms, P <.05).</AbstractText>Prolonged TDR is associated with inducibility as well as spontaneous development of VT in higher risk patients. TDR may be a useful index for predicting ventricular tachyarrhythmias.</AbstractText> |
1,452 | [Risk and prevention of atrial fibrillation of non-valvular origin]. | Atrial fibrillation (AF) is an independent risk factor for ischemic stroke. In patients with AF, cardioembolias present about 10% of ischemic strokes. Transesophageal echocardiography is an ideal instrument for diagnostics of intracardiac thrombi. An aim of the study was to find the high risk markers for stroke in patients with AF of non-valvular origin. The patients have been divided into 2 groups with and without stroke in anamnesis. To search for stroke dependence of clinical and echocardiographic high risk markers, the data were analyzed using Poly Analyst Power statistical package. In the group of the patients with stroke in the anamnesis, echocardiographic markers for high risk of thromboembolia occurred significantly more frequently. Thrombi in the left atrial or its appendage were registered in 12.5% patients without stroke in anamnesis and in 31% of those, who survived stroke. The independent risk factors for stroke were age, AF duration, left ventricular ejection fraction, diabetes mellitus and arterial hypertension. |
1,453 | Cardiac and electrocardiographical manifestations of acute organophosphate poisoning. | To study the extent, frequency and pathogenesis of the cardiac and electrocardiographical manifestations of acute organophosphate poisoning.</AbstractText>37 adult patients admitted over a three-year period with a diagnosis of acute organophosphate or carbamate poisoning were studied prospectively. The clinical features and electrocardiographical finding were recorded.</AbstractText>Cardiac complications developed in 23 patients (62.2 percent). These were: non-cardiogenic pulmonary oedema in eight cases (21.6 percent), electrocardiographical abnormalities including prolonged Q-Tc interval in 14 cases (37.8 percent), ST-T changes in 11 cases (29.7 percent), and conduction defects in two cases (5.4 percent). Sinus tachycardia occurred in 15 patients (40.5 percent) and sinus bradycardia in seven patients (18.9 percent). Hypertension developed in five patients (13.5 percent) and hypotension in four patients (10.8 percent). Five patients (13.5 percent) needed respiratory support because of respiratory depression of which two patients developed intermediate syndrome. Out of 14 patients with prolonged Q-Tc interval, only one had polymorphic ventricular tachycardia of the torsade de pointes type. Two patients died from non-cardiogenic pulmonary oedema and one from ventricular fibrillation, giving a hospital mortality of 8.1 percent.</AbstractText>Cardiac complications usually occur during the first hour after exposure. Hypoxemia, electrolyte derangements and acidosis are major predisposing factors for the development of these complications. Intensive supportive treatment, meticulous respiratory care and administration of atropine in adequate doses vary early in the course of the illness will reduce the mortality.</AbstractText> |
1,454 | Coupled pacing improves cardiac efficiency during acute atrial fibrillation with or without cardiac dysfunction. | Coupled pacing (CP), a method for controlling ventricular rate during atrial fibrillation (AF), consists of a single electrical stimulation applied to the ventricles after each spontaneous activation. CP results in a mechanical contraction rate approximately one-half the rate during AF. Paired stimulation in which two electrical stimuli are delivered to the ventricles has also been proposed as a therapy for heart failure. Although paired stimulation enhances contractility, it greatly increases energy consumption. The primary hypothesis of the present study is that CP improves cardiac function during acute AF without a similar increase in energy consumption because of the reduced rate of ventricular contractions. In a canine model, CP was applied during four stages: sinus rhythm (SR), acute AF, cardiac dysfunction (CD), and AF in the presence of cardiac dysfunction. The rate of ventricular contraction decreased in all four stages as the result of CP. In addition, we determined the changes in external cardiac work, myocardial oxygen consumption, and myocardial efficiency in the each of four stages. CP partially reversed the effects of AF and CD on external cardiac work, whereas myocardial oxygen consumption increased only moderately. In all stages but SR, CP increased myocardial efficiency because of the marked increases in cardiac work compared with the moderate increases in total energy consumed. Thus this pacing therapy may be a viable therapy for patients with concurrent atrial fibrillation and heart failure. |
1,455 | [Brugada syndrome and supraventricular arrhythmias]. | The author reports the case of a 46-year old patient diagnosed with idiopathic ventricular fibrillation (Brugada syndrome) further to induction of class Ic antiarrhythmic therapy for the management of paroxystic ventricular fibrillation. It would appear that this diagnosis is increasingly frequent in young patients with Brugada syndrome shown to be minimal or intermittent on electrocardiograms. Atrial arrhythmia was the only rhythmic pathology objectively evidenced in this patient and the author was consequently led to reconsider its prevalence in patients presenting this syndrome both in the literature and according to his personal experience. |
1,456 | The pseudorestrictive pattern of transmitral Doppler flow pattern after conversion of atrial fibrillation to sinus rhythm: is atrial or ventricular dysfunction to blame? | Patients with paroxysmal atrial fibrillation (AF) who have recently converted from AF to sinus rhythm often exhibit a restrictive Doppler pattern in the transmitral flow (TMF) velocity. However, the mechanism of this phenomenon has not been well defined. We evaluated the temporal change of TMF pattern and hemodynamics after conversion of AF to in sinus rhythm in an animal model. Eight open-chest dogs underwent 3 hours of pacing-induced AF. TMF velocities and pressure data were acquired at baseline (sinus rhythm), immediately after conversion of AF, and every 10 minutes thereafter. Early diastolic TMF velocity was increased immediately after conversion and recovered to the baseline value in 20 minutes. Atrial systolic TMF velocity was reduced after AF and recovered to baseline value in 20 to 30 minutes. Early diastolic/atrial systolic TMF velocity was increased after conversion, and recovered to baseline value in 20 to 30 minutes. The mean left atrial (LA) pressure increased immediately, 10 and 20 minutes after the conversion of AF to sinus rhythm. The left ventricular end-diastolic pressure was increased and positive left ventricular dP/dt and tau were decreased immediately after AF, whereas they recovered within 10 minutes. In conclusion, a pseudorestrictive pattern of TMF after AF occurred as a result of transient LA mechanical functional impairment and increased LA pressure caused by LA stunning. Transient left ventricular diastolic dysfunction also effected the TMF velocity immediately after the conversion from AF to sinus rhythm, although it recovered faster than LA mechanical dysfunction. |
1,457 | Late incidence and predictors of persistent or recurrent heart failure in patients with mitral prosthetic valves. | The study's objective was to examine factors associated with persistent or recurrent congestive heart failure after mitral valve replacement.</AbstractText>Patients who underwent mitral valve replacement with contemporary prostheses (N = 708) were followed with annual clinical assessment and echocardiography. Cox proportional hazard models were developed to evaluate the impact of demographic, comorbid, and valve-related variables on the occurrence of congestive heart failure after mitral valve replacement, defined as the composite outcome of New York Heart Association class III or IV symptoms or death caused by congestive heart failure postoperatively. Factors associated with all-cause mortality were also examined. Models were bootstrapped 1000 times.</AbstractText>The total follow-up was 3376 patient-years (mean 4.8 +/- 3.7 years, range 60 days to 17.1 years). Freedom from New York Heart Association III or IV symptoms or death caused by congestive heart failure was 96.1% +/- 0.8%, 82.7% +/- 1.7%, 66.4% +/- 3.0%, and 38.8% +/- 6.9% at 1, 5, 10, and 15 years, respectively. Preoperative New York Heart Association class, left ventricular grade, atrial fibrillation, coronary artery disease, smoking, persistent tricuspid regurgitation, and redo status predicted congestive heart failure postoperatively (all P <.05). Patients who underwent mitral valve replacement for pure mitral stenosis had less congestive heart failure events after surgery than those with regurgitation or mixed disease. Prosthesis size and elevated transprosthesis gradients were not predictive of freedom from congestive heart failure after mitral valve replacement. Atrial fibrillation, persistent tricuspid regurgitation, and surgical referral for mitral valve replacement at an advanced functional stage were also risk factors for all-cause mortality.</AbstractText>This study identifies the incidence of and risk factors for congestive heart failure and death late after mitral valve replacement. Although prosthesis size has no effect, other potentially modifiable factors such as atrial fibrillation, persistent tricuspid regurgitation, and late surgical referral have a negative impact on freedom from congestive heart failure and overall survival after mitral valve replacement.</AbstractText> |
1,458 | Angiogenic growth factors and/or cellular therapy for myocardial regeneration: a comparative study. | Locally delivered angiogenic growth factors and cell implantation have been proposed for patients with myocardial infarcts without a possibility of percutaneous or surgical revascularization. The goal of this study was to compare the effects of these techniques in an experimental model of myocardial infarct.</AbstractText>Left ventricular myocardial infarction was created in 27 sheep by ligation of 2 coronary arteries. Three weeks after creation of the infarct, animals were randomized into 4 groups. In group 1, sheep received a culture medium injection to the infarct area (control group); group 2 underwent autologous myoblast implantation; group 3 received vascular endothelial growth factor; and group 4 received injection of both vascular endothelial growth factor and myoblasts. Evaluation included serum troponin IC levels, echocardiography (2-dimensional and color kinesis), and immunohistologic studies for quantitative analysis of capillaries (3 months after surgery).</AbstractText>Four animals died of refractory ventricular fibrillation during myocardial infarction; 2 died after surgery because of stroke and 2 because of infections. Serum troponin increased to 45.6 +/- 4.7 ng/mL at postinfarction day 2. Echocardiography at 3 months showed a significant limitation of left ventricular dilation in the cell group (57 +/- 11.1 mL) and in the cell plus vascular endothelial growth factor group (58.6 +/- 6.6 mL: control group, 74.4 +/- 11.2 mL; vascular endothelial growth factor group, 68.1 +/- 3.4 mL). Color kinesis echography showed important improvements of regional fractional area change in the cell group (from 13.6% +/- 0.8% to 21.1% +/- 1.5%) and in the cell plus vascular endothelial growth factor group (from 12.8% +/- 0.9% to 18.7% +/- 2.3%). The number of capillaries increased in the peri-infarct region of the vascular endothelial growth factor group (1036 +/- 75: control group, 785 +/- 31; cell group, 830 +/- 75; cell plus vascular endothelial growth factor group, 831 +/- 83).</AbstractText>In the cell therapy groups, regional ventricular contractility improved and heart dilatation was limited compared with either vascular endothelial growth factor or control; thus, postischemic remodeling was reduced. Angiogenesis was demonstrated in the vascular endothelial growth factor group, without improvement of ventricular function and remodeling. To improve local conditions for cell survival, further studies are warranted on prevascularization of myocardial scars with angiogenic therapy.</AbstractText> |
1,459 | [Risk stratification and prevention of sudden death in patients with heart failure]. | Patients with heart failure can die of progressive refractory heart failure or sudden cardiac death. This article reviews the major clinical predictors of sudden death in patients with heart failure due to left ventricular systolic dysfunction. Although earlier studies have identified many independent univariate predictors of reduced survival in these patients, the positive predictive value of most of them is low. Cardioverter defibrillator implantation has been shown to be the most effective therapy in patients resuscitated after cardiac arrest caused by ventricular fibrillation or poorly tolerated ventricular tachycardia. Low left ventricular ejection fraction, low New York Heart Association functional class, unsustained ventricular tachycardia and inducibility of ventricular arrhythmia in electrophysiological studies may also identify high-risk patients who are candidates for cardioverter defibrillator implantation. The role of amiodarone in preventing sudden death in high-risk patients with heart failure seems to be small. Further studies are needed to improve risk stratification criteria to select patients with heart failure who are candidates for cardioverter defibrillator implantation. |
1,460 | Changes in hematologic markers in patients with mitral stenosis after successful percutaneous balloon mitral valvuloplasty. | Systemic embolism is a major complication of mitral stenosis which is usually related to a presence of left atrial thrombus. Percutaneous balloon mitral valvuloplasty (PBMV) was previously reported to reduce the incidence of this complication. However, the mechanisms of this beneficial procedure was under investigated. The aim of this study was to investigate the changes in coagulation activity, platelet activity and endocardial function in 29 patients with mitral stenosis after successful PBMV. All subjects had good left ventricular systolic function and 48.3% had atrial fibrillation. There was a significant reduction in thrombin-antithrombin complex (TAT) after a successful procedure and the level of thrombomodulin was also significantly higher one month after successful procedure. However, the level of platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG) were increased after this procedure but not achieved the statistical significance. In conclusion, successful PBMV can reduce the prethrombotic state in patients with mitral stenosis. In addition, it may improve endocardial function of the left atrium in those without atrial fibrillation. |
1,461 | Dobutamine stress MRI. Part I. Safety and feasibility of dobutamine cardiovascular magnetic resonance in patients suspected of myocardial ischemia. | The aim of the study was to evaluate safety and feasibility of dobutamine cardiovascular magnetic resonance (CMR) in patients with proven or suspected coronary artery disease. Dobutamine CMR was evaluated retrospectively in 400 consecutive patients with suspicion of myocardial ischemia. Dobutamine was infused using an incremental protocol up to 40 microg/kg body weight per minute. All anti-anginal medication was stopped 4 days before the CMR study and infusion time of dobutamine was 6 min per stage. Hemodynamic data, CMR findings and side effects were reported. Patients with contraindications to CMR (metallic implants and claustrophobia) were excluded from analysis. Dobutamine CMR was successfully performed in 355 (89%) patients. Forty-five (11%) patients could not be investigated adequately because of non-cardiac side effects in 29 (7%) and cardiac side effects in 16 (4%) patients. Hypotension (1.5%) and arrhythmias (1%) were the most frequent cardiac side effects. One patient developed a severe complication (ventricular fibrillation) at the end of the study. There were no myocardial infarctions or fatal complications of the stress test. The most frequent non-cardiac side effects were nausea, vomiting and claustrophobia. Age >70 years, prior myocardial infarction and rest wall motion abnormalities showed no significant differences with side effects (P>0.05). Dobutamine CMR is safe and feasible in patients with suspicion of myocardial ischemia. |
1,462 | Genetic analysis of Brugada syndrome in Western Japan: two novel mutations. | Brugada syndrome is a form of idiopathic ventricular fibrillation characterized by right bundle-branch block pattern and ST elevation in the right precordial leads of the ECG. The SCN5A gene encodes the alpha-subunit of the human heart sodium channel, which plays a critical role in cardiac excitability, and mutations of SCN5A could underlie Brugada syndrome.</AbstractText>To detect mutations of SCN5A, DNA samples from 12 Japanese patients with Brugada syndrome were analyzed using direct sequencing. Two patients had novel mutations, G292S and S835L, but no other mutations of SCN5A were detected in the remaining patients. The first mutation, G292S, was identified adjacent to the pore-lining region between the DIS5 and DIS6 transmembrane segments of SCN5A, and the second mutation, S835L, was in the intracellular loop connecting the DIIS4 to DIIS5. Both mutations were not detected in 100 unrelated control subjects.</AbstractText>Two novel SCN5A mutations have been found in Japanese patients with Brugada syndrome.</AbstractText> |
1,463 | Long-term prognosis of patients with paroxysmal atrial fibrillation depends on their response to antiarrhythmic therapy. | The rhythm control treatment strategy for persistent atrial fibrillation (AF) has been shown not to improve quality of life or prognosis any more than rate control. It is unclear whether the prognosis of the patients with paroxysmal AF (PAF) is influenced by the response to antiarrhythmic drug therapy (AAT).</AbstractText>The relationship between the response to AAT and long-term prognosis was evaluated in 290 patients with PAF (mean age, 69 years). During a mean follow-up period of 51 months, 114 patients (39%) had no recurrence of AF (Group 1), 113 (39%) had repeated AF recurrence (Group 2), and the remaining 63 (22%) had permanent AF despite AAT (Group 3). The survival rate without any cardiovascular deaths at 60 months was 99% in Group 1, 95% in Group 2 and 94% in Group 3 (p=NS among 3 groups). Survival rate without symptomatic ischemic stroke was 99% in Group 1, 88% in Group 2 and 76% in Group 3 (p<0.05 Group 1 vs Groups 2 and 3). The annual rate of stroke in the patients with warfarin treatment was similar among the 3 groups, whereas that in the patients without warfarin was higher in Groups 2 and 3 than in Group 1.</AbstractText>Long-term prognosis of patients with PAF varies with the response to AAT: When sinus rhythm is maintained, the prognosis is good even without anticoagulation therapy.</AbstractText> |
1,464 | Is there a correlation between ventricular fibrillation cycle length and electrophysiological and anatomic properties of the canine left ventricle? | We hypothesized that myocardial infarction-related alterations in ventricular fibrillation (VF) cycle length (VFCL) would correlate with changes in local cardiac electrophysiological and anatomic properties. An electrophysiological study was performed in normal, subacute, and chronic infarction mongrel dogs. VF was induced by programmed electrical stimulation and mean and minimum early and late VFCL was determined and correlated with local electrophysiological and anatomic properties. Effective refractory period (ERP), activation recovery time (ART), ERP/ART ratio, threshold, and ERP and ART dispersion were determined at 112 sites on the anterior left ventricle. Wave front progression was analyzed over a 2-s period. The extent of local tissue necrosis and of myocardial fiber disarray was also evaluated. The early mean VFCL was significantly longer in the subacute infarction (149 +/- 35 ms) and chronic infarction dogs (129 +/- 18 ms) compared with control dogs (102 +/- 15 ms; P < 0.0001 for both comparisons) as was the early minimum VFCL with similar trends seen during late VF. Complete epicardial reentrant circuits were significantly more common in normal dogs (4.3 +/- 2.4, 22.4% of cycles) than in subacute (0.75 +/- 0.96, 5.3% of cycles, P < 0.05 vs. normal) and chronic infarction dogs (1.3 +/- 1.3, 7.5% of cycles, P < 0.05 vs. normal). There was a poor correlation between the mean and minimum early and late VFCL and local electrophysiological and anatomic properties (R(2) < 0.2 for all comparisons) with a much better correlation between average mean and minimum VFCL (over the entire plaque) and global ERP and ART dispersion during early and late VF. In conclusion, VFCL in normal and infarcted myocardium shows a poor correlation with local ventricular electrophysiological and anatomic properties measured in sinus rhythm. However, there was a much better correlation between the average VFCL with global dispersion of repolarization. The lack of correlation between local VFCL and refractoriness and the infrequent occurrence of epicardial reentry suggests that intramural reentry may be the primary mechanism of VF in this model. |
1,465 | First robotic endoscopic epicardial isolation of the pulmonary veins with microwave energy in a patient in chronic atrial fibrillation. | The pulmonary veins have been demonstrated to play an important role in generating atrial fibrillation. We report the first successful endoscopic epicardial isolation of the pulmonary veins in a patient with permanent atrial fibrillation, along with a 1-year follow-up. The procedure consisted of making a conduction block around the pulmonary veins with a flexible microwave energy delivery probe. The probe was placed endoscopically on the left atrial epicardium with the aid of robotic instruments. |
1,466 | Postoperative assessment of the univentricular repair by dynamic radionuclide studies. | The purpose of this investigation was to determine the role of radionuclide studies in evaluating postoperative Fontan hemodynamics and to quantify its diagnostic accuracy.</AbstractText>One hundred five patients (105), aged 11 months to 35 years old, who had undergone univentricular repair, underwent first-pass and multigated acquisition scan 1 month to 10 years after univentricular repair. Forty-five patients with evidence of Fontan failure underwent radionuclide studies using Technetium-99 m as well as cardiac catheterization (group 1). The remaining sixty randomly selected patients with excellent functional status received radionuclide studies alone (group 2). The receiver operating characteristic curve analysis was done to quantify the diagnostic accuracy of the first-pass study.</AbstractText>There was paradoxical filling of the right lung after femoral injection in all cases of tunnel or conduit obstruction. A first-pass transit time of 16 to 25 seconds (mean +/- standard deviation [SD] = 18.82 +/- 2.69) was always associated with Fontan failure and high right atrial pressure (range = 20 to 24 mm Hg, mean +/- SD = 22.02 +/- 1.58). A first-pass transit time of 16 seconds was associated with a sensitivity of 100% and a specificity of 93.33%. The predictive accuracy of a positive or negative result was 91.8% and 100% respectively. The area measured under the receiver operating characteristic curve indicates that 99.41% (SE +/- 0.0035) of the time, the value of first-pass time is higher for the Fontan failure group (group 1) compared to the normal group (group 2; p = 0.000).</AbstractText>Our data indicate that Fontan circuit can be reliably evaluated for both anatomic and functional flaws by radionuclide studies; radionuclide first-pass time may be used to predict the chances of Fontan failure postoperatively as well as its presence; and in the presence of atrial fibrillation with fast ventricular rate, analysis using first-pass radionuclide may be impossible and gated equilibrium radionuclide angiocardiography may be the preferred method. Inspection of the systemic ventricular time-activity curve is of crucial importance in this regard.</AbstractText> |
1,467 | Impact of intraoperative transesophageal echocardiography in patients undergoing valve replacement. | The role of intraoperative transesophageal echocardiography (IOTEE) in valve replacement surgery is not well established. The aim of this study was to explore the impact of immediate postpump IOTEE in valve replacement surgery at a single tertiary medical center.</AbstractText>The departmental database was screened for valve replacement operations (mechanical or bioprosthetic valves) performed during a 55-month period that were succeeded by immediate postpump IOTEE. Data was gathered regarding the impact of IOTEE on the immediate postoperative course.</AbstractText>The study group included 417 patients (44.8% male, 55.2% female, age 65.2 +/- 13.9 years). Prepump IOTEE was performed in 352 patients (84.4%). A single valve was replaced in 336 patients (80.6%) and two or more valves were replaced in 81 patients (19.4%). Overall 501 valves were inserted: mitral, 237 (131 mechanical, 106 biological); aortic, 221 (89 mechanical, 132 biological); tricuspid, 43 (2 mechanical, 41 biological). Unexpected pathologic echocardiographic findings on postpump IOTEE necessitated immediate surgical correction in 15 patients (3.6%): perivalvular leak in 8 patients (4 mitral, 4 aortic), immobilized leaflet in 4 patients (3 mitral, 1 tricuspid), coronary obstruction by an aortic bioprosthesis in 2 patients, and incompetent xenograft in 1 patient. Prolonged removal of air was necessary in 45 patients (10.8%). In 47 patients (11.3%) the postpump IOTEE contributed to the evaluation of difficult weaning from the bypass pump and to its appropriate therapeutic management (volume expansion, inotropic agents, vasodilators, or mechanical assistance).</AbstractText>Immediate postpump IOTEE is an important diagnostic and therapeutic role in valve replacement surgery and should be widely implemented.</AbstractText> |
1,468 | Efficacy of distinct energy delivery protocols comparing two biphasic defibrillators for cardiac arrest. | Limited data have been published on the use of external defibrillators that deliver impedance compensated biphasic (ICB) waveforms in patients. We compared 2 ICB defibrillators, the Heartstream XL (150-150-150 J protocol) and Heartsine Samaritan (100-150-200 J protocol) in 78 consecutive patients in cardiac arrest. The performance of the 2 devices over the first 2 shocks was statistically equivalent. By the third shock, the Heartsine Samaritan had significantly better performance in removing ventricular fibrillation (p = 0.029). Energy selection for ICB waveforms requires further validation. |
1,469 | [Semiautomatic defibrillation in children]. | The main survival factor in cardiac arrest secondary to ventricular fibrillation (VF) is the interval between collapse and defibrillation; consequently, this treatment constitutes one of the most important links in the survival chain in adults. Although VF is a rare cause of out-of-hospital cardiac arrest in children, its detection and treatment is essential because in the pediatric cardiac arrest scenario, VF is the dysrhythmia with the best prognosis. Automated external defibrillators (AED) are simple devices that allow cardiac rhythm to be analyzed; they can also determine whether it is shockable or not with high sensitivity and specificity in adults and children. Currently available evidence has prompted the recommendation of AED use in children older than 1 year without signs of circulation, mainly in the pre-hospital setting and ideally with a dose-limiting device. |
1,470 | Inappropriate single chamber ICD discharges due to supraventricular tachycardia with high degree atrioventricular block. | Supraventricular tachycardia with rapid ventricular response is well recognized as the more frequent cause of single chamber ICD inappropriate therapies. We report here a 18-year-old-woman with surgically corrected transposition of the great arteries who received repetitive inappropriate discharges from an ICD implanted for ventricular tachycardia. Rapid atrial activity during episodes of supraventricular tachycardia with high degree atrioventricular block was oversensed as ventricular fibrillation by a single chamber ICD causing repetitive painful discharges. Pharmacological treatment of the supraventricular tachycardia solved the problem. |
1,471 | [Anatomy of the atria for rhythmologists]. | The anatomy of the atria is always in the mind of interventional rhythmologists. There is a mental superposition of the anatomical structures and the references obtained by different incidences of fluoroscopy and the endocavitary electrocardiogram. But understanding the anatomy also requires a certain knowledge of dissection to determine, for example, the orientation of bundles of muscle fibres and anatomical sections. The sino-atrial node is situated at a distance from the endocardium. It is long and protected by its own artery which makes it difficult to reach. The atrio-ventricular node has multiple posterior expansions which correspond to the sites where radiofrequency ablation is effective. The cavo-tricuspid isthmus is the target zone for the treatment of atrial flutter but radiofrequency ablation which must be long may be applied at three different levels: inferolateral, median (the most common site) or inferoseptal. Finally, atrial fibrillation has incited many studies of the muscular extensions of the left atrium to the pulmonary veins, the morphological variations of these veins and the organisation of the muscle fibres of the left atrial wall. They have inspired new concepts of atrial fibrillation. |
1,472 | [Bidirectional ventricular tachycardias]. | Bidirectional tachycardias are rare arrhythmias. Nevertheless in the sixties and seventies these arrhythmias prompted much work relating to their mechanism. Discussions about the supposed supra-ventricular origin of certain bidirectional tachycardias essentially rested on presumptive arguments based on electrocardiographic analysis. All the electrophysiological investigations which could be performed in tachycardia showed a ventricular origin. The current hypotheses concerning the electrophysiological mechanism favour non-unifocal mechanisms as well as a very diverse aetiology: an automatic focus, or the triggered activities being associated with alternating conduction, or re-entry between the left hemibranches. Although the classic context is of excess digitalis with advanced cardiopathy, readily in atrial fibrillation with a poor prognosis as a corollary, the most recent description of catecholergic ventricular tachycardias with the very characteristic appearance of bidirectional tachycardias justifies updating the understanding of these unusual tachycardias. |
1,473 | [Arrhythmias of primary hypertrophic cardiomyopathy]. | Primary hypertrophic cardiomyopathy is a genetic disease causing sarcomere dysfunction. The structural and functional myocardial changes combine to produce cardiac arrhythmias related to reentry phenomena and to triggered automatic activity. The commonest arrhythmias are atrial fibrillation and ventricular arrhythmias; junctional tachycardias via the bundle of Kent are rare. Atrial fibrillation and the Wolff-Parkinson-White syndrome are more commonly associated with certain genetic mutations. Their treatment is mainly based on medication with amiodarone or on radiofrequency ablation in cases of junctional tachycardia. Ventricular arrhythmias are mainly isolated ventricular extrasystoles and non-sustained ventricular tachycardia. The prognostic significance of the latter has been subject of debate for many years but recent studies report a poor prognosis with non-sustained ventricular tachycardia especially in the young patients. Sustained ventricular tachycardia and ventricular fibrillation, though life-threatening complications of hypertrophic cardiomyopathy, are rarely documented and justify implantation of an automatic defibrillator as the risk of recurrence is high. The main objective of the cardiologist in cases of primary hypertrophic cardiomyopathy is to identify the patient at high risk of sudden death. This requires analysis of several parameters: clinical, anatomical, haemodynamic, rhythmic, functional and genetic. The presence of at least two risk factors for sudden death justifies preventive measures. The implantation of an automatic defibrillator is the most reliable form of treatment. |
1,474 | Transgenic upregulation of IK1 in the mouse heart leads to multiple abnormalities of cardiac excitability. | To assess the functional significance of upregulation of the cardiac current (IK1), we have produced and characterized the first transgenic (TG) mouse model of IK1 upregulation. To increase IK1 density, a pore-forming subunit of the Kir2.1 (green fluorescent protein-tagged) channel was expressed in the heart under control of the alpha-myosin heavy chain promoter. Two lines of TG animals were established with a high level of TG expression in all major parts of the heart: line 1 mice were characterized by 14% heart hypertrophy and a normal life span; line 2 mice displayed an increased mortality rate, and in mice < or =1 mo old, heart weight-to-body weight ratio was increased by >100%. In adult ventricular myocytes expressing the Kir2.1-GFP subunit, IK1 conductance at the reversal potential was increased approximately 9- and approximately 10-fold in lines 1 and 2, respectively. Expression of the Kir2.1 transgene in line 2 ventricular myocytes was heterogeneous when assayed by single-cell analysis of GFP fluorescence. Surface ECG recordings in line 2 mice revealed numerous abnormalities of excitability, including slowed heart rate, premature ventricular contractions, atrioventricular block, and atrial fibrillation. Line 1 mice displayed a less severe phenotype. In both TG lines, action potential duration at 90% repolarization and monophasic action potential at 75-90% repolarization were significantly reduced, leading to neuronlike action potentials, and the slow phase of the T wave was abolished, leading to a short Q-T interval. This study provides a new TG model of IK1 upregulation, confirms the significant role of IK1 in cardiac excitability, and is consistent with adverse effects of IK1 upregulation on cardiac electrical activity. |
1,475 | Analysis of clinical outcomes following in-hospital adult cardiac arrest. | The outcome of in-hospital resuscitation following cardiac arrest depends on many factors related to the patient, the environment and the extent of resuscitation efforts. The aim of the present study was to determine predictors of successful resuscitation and survival to -hospital discharge following in-hospital cardiac arrest and to assess functional outcomes of survivors (cerebral performance scores).</AbstractText>Medical records of adult patients sustaining in-hospital cardiac arrest between June 2001 and January 2003 were reviewed. Successful resuscitation was defined as the return of spontaneous circulation at the completion of resuscitative efforts, irrespective of degree of inotropic/vasopressor support. Thirty demographic and clinical variables were analysed to determine predictors of successful resuscitation and in-hospital survival.</AbstractText>In 105 patients with cardiac arrest, 46 patients (44%) were successfully resuscitated and 22 (21%) survived to hospital discharge. Predictors of successful resuscitation included a primary cardiac admission diagnosis, monitoring at the time of the arrest, a longer duration of resuscitation and the absence of the need for endotracheal intubation. Patients with ventricular tachycardia/fibrillation were more likely to survive to hospital discharge than those with asystolic or pulseless electrical activity (45 vs 12 vs 20%, P = 0.01). The sole independent predictor of survival to hospital discharge was the absence of the need for endotracheal intubation (odds ratio 0.14, 95% confidence interval 0.02-0.88, P < 0.01). The majority of survivors (73%) had normal cerebral performance scores.</AbstractText>Identification of predictors of successful resuscitation following cardiac arrest is important for risk stratification. Ongoing appraisal of in-hospital cardiac arrests through a multicentre registry could improve clinical outcomes.</AbstractText> |
1,476 | Magnetic resonance imaging-based biventricular pacemaker upgrade. | This report describes a patient with drug refractory severe chronic ischemic heart failure, atrial fibrillation with bradycardia, and left bundle branch block who had a failed implantation of a biventricular pacemaker because of a high left ventricular pacing threshold. VVI pacemaker implantation had not improved the patient's condition. MRI-guided biventricular pacemaker upgrade had been performed with a left ventricular epicardial lead at the lateral region where a 4-mm thickening during systole had been proven. After 6 months of effective resynchronization, the patient's functional class improved to NYHA II without further need of hospitalization. |
1,477 | Complete loss of ICD programmability after magnetic resonance imaging. | The purpose of this case report is to describe the effects of an MRI performed on a patient without realizing that an ICD has been previously implanted. After a few seconds of imaging the adversity was recognized and the examination was stopped immediately. The patient was not pacemaker dependent and had neither physical complaints nor electrocardiographic changes in the surface ECG. A consecutively performed ICD assessment showed a backup mode with standard parameters for pacing (VVI 50 beats/min) and arrhythmia detection and treatment. The device could not be programmed by the external programmer. With the exception of printing out the parameters, all software functions were no longer feasible. A device examination by the manufacturer after ICD replacement showed that a major portion of the device memory was corrupt. Even ICDs of a newer generation are susceptible to magnetic interference, with the danger of complete loss of programmability. |
1,478 | Accuracy of atrial tachyarrhythmia detection in implantable devices with arrhythmia therapies. | The clinical application of atrial tachyarrhythmia (AT) episode data stored by implantable devices is presently limited by the high proportion of inappropriate detection. We quantified the percentage of inappropriate AT detection in two implantable devices with AT diagnostics and therapies via meta-analysis of stored AT episodes from a number of clinical trials. The AT500 and GEM III AT, contain dual chamber logic to discriminate AT from ventricular tachycardia and far-field R wave (FFRW) oversensing using dual chamber bipolar electrograms. A subset of data from four clinical trials of 1,142 patients was considered. Manual analysis was performed on 21,553 stored episodes with atrial EGM and marker channel from 409 patients with stored episodes and the market-released device detection configuration. The percentage of episodes with inappropriate detection and termination was evaluated and compared between septal and nonseptal lead locations. The percentage of inappropriately detected episodes receiving ATP therapy was also determined. The percentage of episodes appropriately detected and the percentage of net episode duration (i.e., burden) recorded by the device were also determined from a separate analysis of 24-hour Holter recordings from a subset of 40 patients from one trial. Adjusted estimates of the percentage of appropriate [corrected] detection were 95.3% (93.5-96.7; 95% CI) for AT500 and 95.7% (84.3-98.9) for GEM III AT. Inappropriate detection was primarily due to FFRW oversensing or brief runs of premature atrial contractions (PACs). The device detected 100% of the sustained atrial arrhythmia episodes and 95.3% (range 76.1-99.9) of the net AT duration observed on the Holter recordings. AT detection was not influenced by atrial lead location. Appropriate detection of normal sinus rhythm at episode termination was 83.7% (80.7-86.3) for AT500 and 92.1% (84.5-96.2) for GEM III AT. Accurate detection and discrimination of FFRWs validates the reliability of AT diagnostic data and decreases the risk of inappropriate device therapy. |
1,479 | Surgical open-chest ventricular defibrillation: triphasic waveforms are superior to biphasic waveforms. | Triphasic shocks have been evaluated for endocardial defibrillation but not for open-chest epicardial defibrillation. The purpose of this study was to compare the efficacy and safety of biphasic versus triphasic shocks for epicardial defibrillation in a porcine model. Twenty-two adult swine (18-28 kg) were deeply anesthetized and intubated. After 30 seconds electrically induced VF, each pig received truncated exponential biphasic (7.2-ms positive pulse duration and 7.2-ms negative pulse duration, total waveform duration 14.4 ms) and triphasic (4.8/4.8/4.8 ms, total waveform duration 14.4 ms) epicardial shocks. Pigs in group 1 (n = 11) received epicardial biphasic and triphasic shocks from large hand held paddle electrodes (44.2 cm2); pigs in group 2 (n = 11) received shocks from small paddle electrodes (15.9 cm2). Shocks were given at five selected energy levels (3-30 J) in random sequence. Four shocks were delivered at each energy level to construct an energy versus percentage of success curve. In group 1 (large paddle electrodes), percentage of shock success was significantly higher for triphasic shocks at the energy levels of 3, 5, 10, and 20 J compared to biphasic shocks. In group 2 (small paddle electrodes), triphasic shocks yielded a significantly higher percentage of shock success than biphasic shocks at the energy levels of 5, 10, and 20 J). Shock induced ventricular tachycardia was similar for both waveforms; asystole was rare. For open-chest defibrillation, triphasic waveform shocks were superior to biphasic waveform shocks for VF termination at energy levels of 3-20 J and were as safe as biphasic shocks. |
1,480 | High incidence of appropriate and inappropriate ICD therapies in children and adolescents with implantable cardioverter defibrillator. | Appropriate and inappropriate therapies of implantable cardioverter defibrillators have a major impact on morbidity and quality of life in ICD recipients, but have not been systematically studied in children and young adults during long-term follow-up. ICD implantation was performed in 20 patients at the mean age of 16 +/- 6 years, 11 of which had prior surgical repair of a congenital heart defect, 9 patients had other cardiac diseases. Implant indications were aborted sudden cardiac death in six patients, recurrent ventricular tachycardia in 9 patient, and syncope in 5 patients. Epicardial implantation was performed in 6 and transvenous implantation in 14 patients. Incidence, reasons and predictors (age, gender, repaired congenital heart disease, history of supraventricular tachycardia, and epicardial electrode system) of appropriate and inappropriate ICD therapies were analyzed during a mean follow-up period of 51 +/- 31 months range 18-132 months. There were a total 239 ICD therapies in 17 patients (85%) with a therapy rate of 2.8 per patient-years of follow-up. 127 (53%) ICD therapies in 15 (75%) patients were catagorized as appropriate and 112 (47%) therapies in 10 (50%) patients as inappropriate, with a rate of 1.5 appropriate and 1.3 inappropriate ICD therapies per patient-years of follow-up. Time to first appropriate therapy was 16 +/- 18 months. Appropriate therapies were caused by ventricular fibrillation in 29 and ventricular tachycardia in 98 episodes. Termination was successful by antitachycardia pacing in 4 (3%) and by shock therapy in 123 episodes (97%). Time to first inappropriate therapy was 16 +/- 17 months. Inappropriate therapies were caused by supraventricular tachycardia in 77 (69%), T wave oversensing in 19 (17%), and electrode defect in 16 episodes (14%). It caused shocks in 87 (78%) and only antitachycardia pacing in 25 episodes (22%). No clinical variable could be identified as predictor of either appropriate or inappropriate ICD therapies. There is a high rate of ICD therapies in young ICD recipients, the majority of which occur during early follow-up. The rate of inappropriate therapies is as high as 47% and is caused by supraventricular tachycardia and electrode complications in the majority of cases. Prospective trials are required to establish preventative strategies of ICD therapies in this young patient population. |
1,481 | Excessive increase in QT interval and dispersion of repolarization predict recurrent ventricular tachyarrhythmia after amiodarone. | Although chronic amiodarone has been proven to be effective to suppress ventricular tachycardia (VT) and ventricular fibrillation (VF), how we predict the recurrence of VT/VF after chronic amiodarone remains unknown. This study evaluated the predictive value of the QT interval, spatial, and transmural dispersions of repolarization (SDR and TDR) for further arrhythmic events after chronic amiodarone. Eighty-seven leads body surface ECGs were recorded before (pre) and one month after (post) chronic oral amiodarone in 50 patients with sustained monomorphic VT associated with organic heart disease. The Q-Tend (QTe), the Q-Tpeak (QTp), and the interval between Tpeak and Tend (Tp-e) as an index of TDR were measured automatically from 87-lead ECG, corrected Bazett's method (QTce, QTcp, Tcp-e), and averaged among all 87 leads. As an index of SDR, the maximum (max) minus minimum (min) QTce (max-min QTce) and standard deviation of QTce (SD-QTce) was obtained among 87 leads. All patients were prospectively followed (15 +/- 10 months) after starting amiodarone, and 20 patients had arrhythmic events. The univariate analysis revealed that post max QTce, post SD-QTce, post max-min QTce, and post mean Tcp-e from 87-lead but not from 12-lead ECG were the significant predictors for further arrhythmic events. ROC analysis indicated the post max-min QTce > or = 106 ms as the best predictor of events (hazard ratio = 10.4, 95%, CI 2.7 to 40.5, P = 0.0008). Excessive QT prolongation associated with increased spatial and transmural dispersions of repolarization predict the recurrence of VT/VF after amiodarone treatment. |
1,482 | Effects of sinus rhythm restoration in patients with persistent atrial fibrillation: a clinical, echocardiographic and hormonal study. | The hemodynamic consequences of atrial fibrillation (AF) may lead to impairment of the left ventricular function and a reduction in exercise capacity. Studies on mechanical and neurohormonal remodelling in patients with AF are becoming increasingly important. The results could possibly enhance treatment strategies of these patients. The aim of this study was to assess changes in exercise capacity, echocardiographic findings and plasma atrial natriuretic peptide (ANP) concentrations in patients with non-rheumatic persistent AF, before and 30 days after successful cardioversion.</AbstractText>We attempted cardioversion in 42 consecutive patients, aged 58 +/- 8 years, with persistent non-valvular AF of duration 7.1 +/- 7.1 months. They underwent echocardiography examination and submaximal exercise testing 24 h before and 30 days after cardioversion. Exercise capacity was determined during symptom-limited exercise testing, according to a modified Bruce protocol with peak VO2 analysis. Plasma samples of ANP were obtained at rest: before, the day after, and 30 days after cardioversion therapy, and were prepared by refrigerated centrifugation and stored until radioimmunoassay. The control study group, without AF, comprised of 11 subjects.</AbstractText>Cardioversion was successful in 35 patients. However, in six of the 35 patients, AF reappeared within 1 month. There were no statistical differences before cardioversion in exercise tolerance and ejection fraction of left ventricle between the group with successful cardioversion and the group with unsuccessful cardioversion or with recurrence of AF. On the 30th day after cardioversion we recorded a significant increase in exercise tolerance: duration of exercise 13.7 +/- 3.2 versus 9.5 +/- 3.4 min, (P < 0.05); peak oxygen consumption 32.2 +/- 3.6 versus 19.85 +/- 3.5 ml/min per kg, (P < 0.05); and ejection fraction of left ventricle 58.6 +/- 9.4 versus 52.7 +/- 10.2% (P < 0.05); in the sinus rhythm group. There was no significant improvement observed in the AF group. The mean baseline ANP level was 58.5 +/- 15.7 pg/ml in the study group and 34.3 +/- 10.2 pg/ml in the control group (P < 0.01). The successful therapy reduced significantly the pretreatment mean plasma ANP concentration from 58.5 +/- 15.7 to 31.4 +/- 15.0 pg/ml, (P < 0.01); the day after cardioversion, in the group of 35 patients. It remained stable for the next 30 days (36.9 +/- 15.2 pg/ml) in the group of 29 patients who remained in sinus rhythm, and increased to 53.4 +/- 16.4 pg/ml in the group of six patients who had recurrence of AF. Plasma ANP did not change in the group of seven patients with unsuccessful cardioversion.</AbstractText>The restoration of sinus rhythm in patients with persistent AF was associated with a significant improvement in cardiac performance and exercise tolerance 1 month after cardioversion. Such improvement was not observed in the group with unsuccessful cardioversion or with AF recurrence. The plasma ANP concentration in patients with AF was significantly reduced after successful cardioversion and remained stable for a period of 30 days.</AbstractText>Copyright 2003 Elsevier Ireland Ltd.</CopyrightInformation> |
1,483 | Acute effects of direct cell implantation into the heart: a pressure-volume study to analyze cardiac function. | To safely implant cells into the myocardium, we must establish a volume that prevents compromising cardiac performance. We studied pressure-volume (PV) to investigate the adverse effects of direct cell implantation in the acute phase.</AbstractText>We used 21 minipigs. In the normal heart model, we studied PV by measuring various parameters (including end-systolic pressure, end-systolic elastance, dp/dtmax, end-diastolic volume, and time constant of isovolumetric left ventricular pressure fall [Tau]). We injected solutions into the left ventricular free wall (15 cm(2)). Sampling points were at baseline and after injection of saline (Group I, n = 4) or of blood (Group II, n = 4) at volumes of 1 ml and 10 ml up to 30 minutes after injection. In Group II, we injected additional blood (10 ml) 4 times. In the ischemic heart model, 1 month after ligating the left anterior descending artery, we injected 1 ml saline (Group III, n = 4), bone marrow mononuclear cells (10(8) cells/1 ml; Group IV, n = 4), or bone marrow stromal cells (10(8) cells/1 ml; Group V, n = 3). We studied PV before and after injection.</AbstractText>In Group I, we found no significant changes in parameters. In Group II, end-diastolic volume after 10-ml injection (24.4 +/- 3.6 ml) was smaller than end-diastolic volume at baseline (29.5 +/- 5.8 ml, p < 0.01). Tau after 10-ml injection (39.4 +/- 5.3 msec) was greater than at baseline (35.6 +/- 4.0 msec, p < 0.01). One pig died of ventricular fibrillation after a 20-ml injection of blood. We observed no detrimental effects in Groups III, IV, and V.</AbstractText>More than 10 ml cell suspension compromised diastolic function. We safely performed direct injection of bone marrow cells (1 x 10(8)/1 ml).</AbstractText> |
1,484 | L-thyroxine increases susceptibility of adult rats to low K+-induced ventricular fibrillation, and sinus rhythm restoration in old rats. | Hypokalaemia increases the risk for life-threatening arrhythmias; however, data about interaction with thyroid status are lacking. The aim of this study was to investigate vulnerability of l-thyroxine (T(4))-treated adult and old rats to low K(+)-induced ventricular fibrillation (VF) as well as the ability of the heart to recover sinus rhythm. The experiments were performed on isolated heart preparations using the heart of 4- and 20-month-old female Wistar rats without and with feeding with T(4) 50 microg (100 g day)(-1) over a period of 2 weeks. Perfusion of the isolated heart with oxygenated Krebs-Henseleit solution at constant pressure was followed by perfusion with K(+)-deficient solution until occurrence of VF (< 10 min). After 2 min of sustained VF, the heart was perfused with normal solution for 10 min, during which sinus rhythm was restored. ECG, left ventricular pressure (LVP) and coronary flow were continuously monitored. The results showed that compared with untreated rats, the onset of low K(+)-induced ventricular premature beats was delayed and their number was significantly decreased in both T(4)-treated groups. Nevertheless, VF occurred earlier in T(4)-treated than in non-treated adult rats (6.78 +/- 0.28 vs. 9.59 +/- 0.55 min, P < 0.05), whereas the difference was not significant in aged animals. Furthermore, sinus rhythm appeared earlier in old T(4)-treated rats compared with non-treated rats (7.18 +/- 0.57 vs. 8.94 +/- 0.64 min, P < 0.05), whereas in adult hearts it set in at practically the same time regardless of treatment. In conclusion, our results indicate that administration of a pharmacological dose of T(4) can increase the risk of low K(+)-induced VF in adult but not in old animals; in the latter it even facilitated restoration of sinus rhythm. Moreover, enhanced mechanical function was observed in both adult and old T(4)-treated hearts. |
1,485 | Troponin I in atrial fibrillation with no coronary atherosclerosis. | A number of reports have raised the possibility that myocardial strain could be associated to increased plasma levels of troponin I. A 69-year-old, male, Caucasian, patient was admitted with prolonged chest pain and dyspnoea. The electrocardiogram showed atrial fibrillation with a ventricular rate of about 120 to 150/minute. After treatment with digoxin and amiodarone, the patient returned to sinus rhythm. An elevation in the plasma levels of troponin I was noted, with a maximum value of 0.66 ng/ml. Coronary angiography showed absence of coronary artery atherosclerotic lesions. Atrial fibrillation of recent onset and with a relatively high heart rate may be yet another situation in which acute myocardial strain could be the cause of the abnormal release of cardiac troponin I. |
1,486 | Thrombi in left ventricular hypertrabeculation/noncompaction--review of the literature. | Left ventricular hypertrabeculation/noncompaction (LVHT) is diagnosed when numerous, excessively prominent trabeculations and deep interventricular recesses are found in the left ventricle. Although it is assumed that the intertrabecular recesses are a location prone to thrombus formation, the prevalence of thrombi in LVHT hearts is unknown.</AbstractText>A Medline research was carried out looking for reports of pathoanatomical investigations of LVHT hearts. Excluded were reports in which a connection between the coronary arteries with the intertrabecular recesses were described.</AbstractText>In 22 articles pathoanatomical findings of 37 hearts were described (9 women, 27 men, 1 not indicated). The age ranged from 26 gestational weeks to 80 years. Twenty-four hearts were investigated by autopsy, 13 as explanted hearts. The left ventricle was dilated in 29 patients. In 9 patients, a previous embolic event had occurred. All 9 patients had additional risk factors for embolism such as atrial fibrillation (n = 1), left ventricular dysfunction (n = 5) or atrial fibrillation and left ventricular dysfunction (n = 3). In only 2 patients, a thrombus was detected pathoanatomically.</AbstractText>Thrombus-formation is a rare event in patients with LVHT. From these data we infer that LVHT in itself is no indication for oral anticoagulation. However, if additional cardiac abnormalities, known to increase the risk of embolism, like atrial fibrillation or left ventricular systolic dysfunction, accompany LVHT, they have to be treated as usual.</AbstractText> |
1,487 | Thyroid storm and ventricular tachycardia. | A 34-year-old woman was brought to our emergency department because of sudden loss of consciousness. Ventricular tachycardia and fibrillation were noted on electrocardiographic monitoring and reverted to sinus rhythm after repeated defibrillation. She was treated as a case of thyroid storm. Although tachycardia and fever normalized after 2 days, she remained comatose and died. This is an unusual case because the patient's initial presentation was cardiac arrest without previous history of cardiac disease. To our knowledge, this is the first reported case where ventricular tachyarrhythmia was the initial presenting sign of thyroid storm. |
1,488 | Rapid access arrhythmia clinic for the diagnosis and management of new arrhythmias presenting in the community: a prospective, descriptive study. | To investigate whether a rapid access approach is useful for the evaluation of patients with symptoms suggestive of a new cardiac arrhythmia.</AbstractText>Prospective, descriptive study.</AbstractText>Secondary care based rapid access arrhythmia clinic in West London, UK.</AbstractText>Patients referred by their general practitioner or the emergency department with symptoms suggestive of a new cardiac arrhythmia.</AbstractText>Number of patients with a newly diagnosed significant arrhythmia. Number of patients with diagnosed atrial fibrillation. Number of eligible, moderate, and high risk patients treated with warfarin.</AbstractText>Over a 25 month period 984 referrals were assessed. The mean age was 55 years (range 20-90 years) and 56% were women. The median time from referral to assessment was one day. A significant cardiac arrhythmia was newly diagnosed in 40% of patients referred to the RAAC. The most common arrhythmia was atrial fibrillation, with 203 new cases (21%). Of these, 74% of eligible patients over 65 were treated with warfarin. Other arrhythmias diagnosed were supraventricular tachycardias (127 (13%)), conduction disorders (43 (4%)), and non-sustained ventricular tachycardia (21 (2%)). Vasovagal syncope was diagnosed for 53 patients (5%). The most frequent diagnosis was symptomatic ventricular and supraventricular extrasystoles (355 (36%)).</AbstractText>A rapid access arrhythmia clinic is an innovative approach to the diagnosis and management of new cardiac arrhythmias in the community. It provides a rapid diagnosis, stratifies risk, and leads to prompt initiation of effective treatment for this population.</AbstractText> |
1,489 | Identification and ablation of atypical atrial flutter. Entrainment pacing combined with electroanatomic mapping. | Differentiation between typical and atypical atrial flutter solely based upon surface ECG pattern may be limited. However, successful ablation of atrial flutter depends on the exact identification of the responsible re-entrant circuit and its critical isthmus. Between August 2001 and June 2003, we performed conventional entrainment pacing within the cavotricuspid isthmus in 71 patients with sustained atrial flutter. In patients with positive entrainment we considered the arrhythmia as typical flutter and treated them with conventional ablation of the cavotricuspid isthmus. As a consequence of negative entrainment we performed 3D-electroanatomic activation mapping (CARTO trade mark ). Conventional ablation of the right atrial isthmus was successful in all patients (n = 54) with positive entrainment. We performed electroanatomic mapping in the remaining 17 patients (14 male; age 60.9 +/- 16 years) resulting in the identification of 6 cases with typical and 11 cases with atypical flutter. Therefore, entrainment pacing was able to predict the true presence of typical atrial flutter in 91.5%. Atypical flutter was right sided in 4 patients and left sided in 7 cases. Electrically silent ("low voltage") areas probably demonstrating atrial myopathy were identified in all cases with left sided and in 2 patients with right sided flutter. In these patients targets for ablation lines were located between silent areas and anatomic barriers (inferior pulmonary veins, mitral respectively tricuspid annulus, or vena cava inferior). In 1 patient, the investigation was stopped due to variable ECG pattern and atrial cycle lengths. In the remaining cases, ablation was acutely successful. One patient, after surgical closure of a ventricular septal defect, demonstrated a dual-loop intra-atrial reentry tachycardia dependent on two different isthmuses. This arrhythmia required ablation of those distinct isthmuses to be interrupted. After a mean follow-up of 8.8 +/- 3.4 months, there was one patient with a recurrence of left-sided atrial flutter. Another patient developed permanent atrial fibrillation shortly after the procedure. Mean duration time of the procedure was 235.6 +/- 56.4 min (right atrium: 196 +/- 17.3 min; left atrium: 267.2 +/- 59.5 min), and average fluoroscopy time was 21.8 +/- 11.7 min (right atrium: 9.5 +/- 6 min; left atrium: 28.9 +/- 7 min). There was no incidence of serious complications associated with these procedures. In conclusion, conventional pacing in the cavotricuspid isthmus combined with electroanatomic mapping was an effective method to differentiate between typical and atypical atrial flutter. Electroanatomic mapping was a powerful tool both for identification of different atrial re-entrant circuits including their critical isthmuses as well as for effective application of individual ablation line strategies. |
1,490 | [Cardiac arrhythmias and sudden cardiac death in women]. | Gender specific cardiac arrhythmias have been recognized for more than 80 years. The impact of gonadal steroids on the autonomic system and on the cellular electrophysiology of the cardiac autonomic system are discussed as is a direct genetic disposition on a cellular, functional or metabolic level. We nevertheless have to be aware of age- and gender-specific differences of heart diseases, which have an impact on the incidence, form and severity of cardiac arrhythmias.</AbstractText>Gender-specific electrophysiologic differences like a higher basic heart rate and a longer QT-interval, beginning after puberty, are the main changes in ECGs in women and have a strong relationship to constitutional and hormonal influences. Supraventricular arrhythmias, i. e. in women sinus and AV-nodal-reentry tachycardias, less frequently Wolff-Parkinson-White tachycardias, may show clearly cyclical differences. Atrial fibrillation is more frequent in women, is more symptomatic, and there are more problems in therapy. Ventricular arrhythmias, occurring equally in healthy persons, show a strong relationship to coronary artery disease in men, which is less significant in women (in women more arrhythmogenic co-factors). Women suffer from acquired and congenital long-QT syndrome, and consequently more often from torsade-de-pointes tachycardias (stronger drug-induced QT-lengthening, more short-long sequences, differences in Ikr sensitivity). Sudden cardiac death is three times more often in men. Women suffer from it about ten years later; it is a more heterogenous phenomenon than in men, and the prognosis is worse. Women are underrepresented in controlled studies for primary and secondary prevention compared to men.</AbstractText>As the underlying reasons of gender-specific differences in cardiac arrhythmias are not known in detail, the findings discussed imply the necessity of more basic studies to evaluate gender-specific solutions for risk stratification and therapy.</AbstractText> |
1,491 | Cardiac consequences of hypertension in hemodialysis patients. | Hypertension in end-stage renal disease (ESRD) is an important risk factor for left ventricular hypertrophy (LVH), cardiac failure, coronary artery disease (CAD), and arrhythmia. LVH is generally considered an integrator of the long-term effects of hypertension and other cardiovascular (CV) risk factors and represents the strongest predictor of adverse CV outcomes in ESRD patients. The risk of heart failure is higher in patients with a history of hypertensive renal disease than in those with other diagnoses. Both coronary heart disease (CHD) and LVH predict congestive heart failure, which is often the ultimate cause of death in patients with cardiac ischemia or LVH. A history of long-standing hypertension is associated with ischemic heart disease both in cross-sectional and prospective studies in ESRD. Atrial fibrillation and ventricular arrhythmias are highly prevalent in dialysis patients and are implicated in mortality and sudden death in this population. Despite the lack of evidence from randomized controlled trials, it appears reasonable that interventions aimed at curbing the high CV mortality of ESRD should be targeted to both hypertension and LVH. |
1,492 | Electrophysiologic effects of nicorandil on the guinea pig long QT1 syndrome model. | The slow component of the delayed rectifier K+ current IKs modulates repolarization of the cardiac action potential (AP), and the loss of IKs is known to cause long QT1 (LQT1) syndrome by prolonging action potential duration (APD). In this study, we generated a guinea pig LQT1 syndrome model using the IKs blocker chromanol 293B and then assayed the electrophysiologic effects of the ATP-sensitive potassium channel IK,ATP opener nicorandil on this model.</AbstractText>Transmembrane action potentials of perfused right ventricular papillary muscle preparations and both in vitro and in vivo ECGs of guinea pigs were recorded. Blockade of IKs by chromanol 293B (30 microM) prolonged the action potential duration at 90% repolarization (APD90) by 8.5% and QT interval by 16.5% of control values. In addition, proarrhythmic early afterdepolarizations (EADs) and ventricular fibrillation were observed. Venoinjection of chromanol 293B (1 mg/kg) revealed 10.9% QT prolongation. Nicorandil (5-30 microM) dose-dependently shortened APD90 under the control condition, whereas it reversed the AP prolongation effect of chromanol 293B by 7.4% at the 30 microM concentration. Moreover, nicorandil shortened QT intervals both in vitro and in vivo and displayed an inhibitory effect on EADs and ventricular fibrillation.</AbstractText>The ATP-sensitive potassium channel opener nicorandil may be an effective drug in the therapy of LQT1 syndrome by shortening APD and the QT interval.</AbstractText> |
1,493 | Effect of rapid biphasic shock subpulse switching on ventricular defibrillation thresholds. | The aim of this study was to demonstrate that significant reductions in defibrillation threshold (DFT) can be achieved by rapidly switching defibrillation pulses within an overall biphasic envelope between multiple endovascular electrode sets.</AbstractText>Defibrillation electrodes were implanted in four locations in nine anesthetized swine (41.7 +/- 8.7 kg). Electrodes were implanted into the right ventricular apex (RV), the superior vena cava (SVC), over the left pectoral region as a "hot can" (Can), and within the middle cardiac vein on the posterior left ventricular (LV) surface. The 50% DFT (level for which 50% of delivered shocks successfully defibrillated) for control shocks (7-ms first phase, 0.5-ms interpulse period, 4-ms second phase, RV- --> SVC+ + Can+) were determined to have energy of 20.5 +/- 5.5 J (mean +/- SD). Mean 50% DFTs were also determined for waveforms that split each phase of the same overall biphasic waveform between various electrode sets. Each phase was divided into 2, 3, 4, or 6 subpulses, the defibrillation shock was sequentially delivered to multiple electrode sets, and DFTs were determined (11.9 +/- 4.8 J, 11.7 +/- 2.9 J, 17.9 +/- 8.7 J, 16.7 +/- 6.1 J, respectively). DFT energy was statistically lower than the control (Wilcoxon sign rank test; P < 0.05) when each phase was divided into 2 or 3 subpulses.</AbstractText>Rapid shock switching within an overall biphasic waveform between electrode sets including an electrode in the middle cardiac vein potentially can lower DFT energy by 40% or more.</AbstractText> |
1,494 | Optimization of atrial defibrillation with a dual-coil, active pectoral lead system. | Atrial defibrillation can be achieved with standard implantable cardioverter defibrillator (ICD) leads, but the optimal shocking configuration is unknown. The objective of this prospective study was to compare atrial defibrillation thresholds (DFTs) with three shocking configurations that are available with standard ICD leads.</AbstractText>This study was a prospective, randomized, paired comparison of shocking configurations on atrial DFTs in 58 patients. The lead system evaluated was a transvenous defibrillation lead with coils in the superior vena cava (SVC) and right ventricular apex (RV) and a left pectoral pulse generator emulator (Can). In the first 33 patients, atrial DFT was measured with the ventricular triad (RV --> SVC + Can) and unipolar (RV --> Can) shocking pathways. In the next 25 patients, atrial DFT was measured with the ventricular triad and the proximal triad (SVC --> RV + Can) configurations. Delivered energy at DFT was significantly lower with the ventricular triad compared to the unipolar configuration (4.7 +/- 3.7 J vs 10.1 +/- 9.5 J, P < 0.001). Peak voltage and shock impedance also were significantly reduced (P < 0.001). There was no significant difference in DFT energy when the ventricular triad and proximal triad shocking configurations were compared (3.6 +/- 3.0 J vs 3.4 +/- 2.9 J for ventricular and proximal triad, respectively, P = NS). Although shock impedance was reduced by 13% with the proximal triad (P < 0.001), this effect was offset by an increased current requirement (10%).</AbstractText>The ventricular triad is equivalent or superior to other possible shocking pathways for atrial defibrillation afforded by a dual-coil, active pectoral lead system. Because the ventricular triad is also the most efficacious shocking pathway for ventricular defibrillation, this pathway should be preferred for combined atrial and ventricular defibrillators.</AbstractText> |
1,495 | Association of anti-heat shock protein 65 antibodies with development of postoperative atrial fibrillation. | Atrial fibrillation (AF) is a frequently encountered arrhythmia after cardiac surgery, but its underlying mechanisms are still unclear. We hypothesize that autoimmune and inflammatory responses against heat shock protein 65 (HSP65) may be involved and hence examined the relationship between HSP65 autoantibodies and occurrence of postoperative AF.</AbstractText>A prospective study of 329 patients undergoing elective primary CABG was undertaken. Cardiovascular risk factors, ECG characteristics, medications, and intraoperative and postoperative features were documented. Anti-HSP65 antibodies and C-reactive protein levels were measured in all preoperative blood samples with ELISA. Postoperative AF was defined as the characteristic arrhythmia, lasting for at least 15 minutes and confirmed on 12-lead ECG and occurring within the first postoperative week. This occurred in 62 patients (19%). In univariate analysis, HSP65 antibodies were significantly higher in patients with postoperative AF (P=0.02). History of previous myocardial infarction, duration of bypass, number of distal anastomosis, and duration of ventilation were also associated with AF (P<0.05), but C-reactive protein levels were not (P=0.13). Multivariate analysis confirmed the positive association of HSP65 antibodies with postoperative AF (OR, 1.41; P=0.04) independent of age, sex, other cardiovascular risk factors, severity of coronary artery disease, duration of ventilation, duration of bypass, and left ventricular function.</AbstractText>We report a novel association between anti-HSP65 antibodies and occurrence of postoperative AF, indicating a possible role for antibody-mediated immune response in its pathogenesis.</AbstractText> |
1,496 | Atrial activity extraction for atrial fibrillation analysis using blind source separation. | This contribution addresses the extraction of atrial activity (AA) from real electrocardiogram (ECG) recordings of atrial fibrillation (AF). We show the appropriateness of independent component analysis (ICA) to tackle this biomedical challenge when regarded as a blind source separation (BSS) problem. ICA is a statistical tool able to reconstruct the unobservable independent sources of bioelectric activity which generate, through instantaneous linear mixing, a measurable set of signals. The three key hypothesis that make ICA applicable in the present scenario are discussed and validated: 1) AA and ventricular activity (VA) are generated by sources of independent bioelectric activity; 2) AA and VA present non-Gaussian distributions; and 3) the generation of the surface ECG potentials from the cardioelectric sources can be regarded as a narrow-band linear propagation process. To empirically endorse these claims, an ICA algorithm is applied to recordings from seven patients with persistent AF. We demonstrate that the AA source can be identified using a kurtosis-based reordering of the separated signals followed by spectral analysis of the sub-Gaussian sources. In contrast to traditional methods, the proposed BSS-based approach is able to obtain a unified AA signal by exploiting the atrial information present in every ECG lead, which results in an increased robustness with respect to electrode selection and placement. |
1,497 | [Psychiatric complication of an implanted automatic defibrillator]. | The implantable automatic defibrillator has completely changed the prognosis of potentially fatal ventricular arrhythmias by the delivery of an electric shock in the event of ventricular tachycardia or fibrillation. This vital device is sometimes poorly accepted from the psychological point of view by patients having been traumatised by experiences of sudden death from which they have been rescuscitated. Anxiety and depression are common and they have an important effect on the quality of life. The unpredictable occurrence of painful, multiple and uncontrollable electrical shocks may induce a state of acute stress with stunning, the resemblance of which to the model of learned helplessness described experimentally in the animal by Seligman, is discussed. The authors report the case of a 20 year old man whose automatic defibrillator was activated twenty times in one night. His state of stress and impotence was such that he lay prostate in his bed. Suicide seemed to be the only possible way of escaping from the electrical shocks of the device which was perceived as being dangerous. The management of this condition is not standardised but it requires the collaboration of the cardiac rhythmological and psychiatric teams. Medication with antidepressant drugs alone is not sufficient. The regulation of the sensitivity of the defibrillator gives the patient a feeling of mastering the situation: submission is not total! Research along this line should improve the patients' acceptation of the device and their quality of life. |
1,498 | [Risk factors for cardiac mortality in cases of syncope with previous history of myocardial infarction]. | Syncope is considered to be a clinical sign predictive of sudden death in patients with a previous history of myocardial infarction. The aim of this study was to determine the prognostic factors in this population. The study population included 228 patients with myocardial infarction over one month old and who had no documented ventricular tachycardia. The patients were referred for investigation of syncope. The left ventricular ejection fraction (LVEF) was measured by echocardiography or radionucleide technique. Complete electrophysiological study including programmed atrial and ventricular stimulation was performed in all cases. The patients were followed up for 6 months to 5 years or until cardiac transplantation (average 3+/-1 years). One hundred and nineteen patients had a LVEF <40% (Group I) and 109 patients had a LVEF >40% (Group II). Sustained monomorphic ventricular tachycardia (VT) with a rate inferior to 280/min was induced in 44 patients in Group I (37%) and in 18 patients in Group II (16.5%), p<0.05. Ventricular flutter or fibrillation was induced in 24 patients in Group I (19%) and in 19 patients in Group II (17%) (NS). Different causes of syncope (conduction disturbances, supraventricular tachycardia, increased vagal tone, severe coronary ischaemia) were found in 23 patients in Group I (19%) and 32 patients in Group II (29%) (NS). Syncope was unexplained in 43 patients in Group I (36%) and 40 patients in Group II (37%) (NS). The prognosis was very different. In Group I, the cardiac mortality was 49% in patients with inducible monomorphic VT <280/min, 35% in those with inducible ventricular flutter or fibrillation but only 9% in patients without inducible ventricular arrhythmias. In Group II, the prognosis was independent of the results of programmed stimulation and much better: cardiac mortality was 5.5% in patients with inducible VT, 5% in those with inducible ventricular flutter or fibrillation and 4% in patients without inducible ventricular arrhyhtmias. The authors conclude that LVEF is the most powerful predictor of cardiac mortality and sudden death in cases of syncope with a past history of myocardial infarction. The prognosis also depends on the results of programmed ventricular stimulation when the LVEF is inferior to 40%. Sustained monomorphic VT is the most frequently induced arrhythmia in this case and the prognosis of these patients is particularly poor. On the other hand, syncope does not appear to be a poor prognostic factor in the group with normal LVEF, even when it is possible to induce VT. |
1,499 | Low serum triiodothyronine in acute myocardial infarction indicates major heart injury. | In patients with acute myocardial infarction (MI), low serum triiodothyronine (T3) concentration is commonly associated with a severe clinical course. The aim of this prospective study was to investigate whether a severe clinical course in patients with low T3 is related to the magnitude of myocardial injury assessed by echocardiography.</AbstractText>Out of 635 patients with MI we enrolled 100 consecutive patients. They were divided in two subgroups: group A, 81 patients without clinical hard events (death, resuscitation following ventricular tachycardia/vertricular fibrillation, new MI) and group B, 19 patients in whom at least one of the above hard events occurred during hospital stay. Thyroid function tests were performed on day 1, 4 and 7, echocardiographic examinations measuring asynergic area (AA), and wall motion score index (WMSI) between day 1 and 5 (median 3). A negative correlation was found between plasma free triiodothyronine (FT3), concentration and AA (p<0.001), FT3 and WMSI (p<0.001) values at all time points. FT3 concentration was lower in group B than group A at all time points (p<0.001).</AbstractText>In patients with acute MI, low FT3 state is related to the extent of myocardial damage.</AbstractText> |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.