Unnamed: 0
int64 0
2.34M
| title
stringlengths 5
21.5M
| abst
stringlengths 1
21.5M
|
|---|---|---|
6,600 | Recurrence of ventricular arrhythmias in ischaemic secondary prevention implantable cardioverter defibrillator recipients: long-term follow-up of the Leiden out-of-hospital cardiac arrest study (LOHCAT). | To assess the long-term rate of mortality and the recurrence of potentially life-threatening ventricular arrhythmias in secondary prevention implantable cardioverter defibrillator (ICD) patients and to construct a model for baseline risk stratification.</AbstractText>Since 1996, all patients with ischaemic heart disease, receiving ICD therapy for secondary prevention of sudden death, were included in the current study. Patients were evaluated at implantation and during long-term follow-up. A total of 456 patients were included in the analysis and followed for 54 +/- 35 months. During follow-up, 100 (22%) patients died and ICD therapy was noted in 216 (47%) patients, of which 138 (30%) for fast, potentially life-threatening ventricular arrhythmia. Multivariate analysis revealed a history of atrial fibrillation or flutter (AF), ventricular tachycardia as presenting arrhythmia, and wide QRS and poor left ventricular ejection fraction as independent predictors of life-threatening ventricular arrhythmias. The strongest predictor was AF with a hazard ratio of 2.1 (95% confidence interval 1.3-3.2). On the basis of the available clinical data, it was not possible to identify a group which exhibited no risk on recurrence of potentially life-threatening ventricular arrhythmias.</AbstractText>Ischaemic secondary prevention ICD recipients exhibit a high recurrence rate of potentially life-threatening ventricular arrhythmias. Factors that increase risk can be identified but, even with these factors, it was not possible to distinguish a recurrence-free group.</AbstractText> |
6,601 | Clinical study of 39 Chinese patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy. | There are few studies on the clinical profile of Chinese patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). The purpose of this study was to describe the clinical characteristics of ARVD/C patients from China, particularly to define the features of electrocardiograph and treatment outcomes.</AbstractText>Thirty-nine patients hospitalized in Fu Wai Cardiovascular Hospital from 1998 to 2006 were included. The data were obtained from the medical archive and the follow-up records.</AbstractText>Of these patients 33 were male and 6 female (age at the first presentation was (34.9 +/- 9.8) years). The most common symptoms were palpitation (62%) and syncope (44%). Right precordial QRSd >or= 110 ms was detected in 69% of the patients, epsilon wave in 59%, and a ratio of QRSd in V(1) + V(2) + V(3)/V(4) + V(5) + V(6) >or= 1.2 in 82%. The most frequent features of electrocardiogram in patients without right bundle-branch block were T-wave inversions and S-wave upstroke in V(1)-V(3) >or= 55 ms (96% and 90% of 28 patients, respectively). Radiofrequency catheter ablation (RFCA) for ventricular tachycardia (VT) was successful in 15 (68%) of 22 patients. The recurrence rate of VT was 46% (7/15) during the follow-up of (16.7 +/- 11.2) months. Seven patients had cardioverter/defibrillator (ICD) implanted plus drug therapy and 17 patients took antiarrhythmic drugs alone. During the follow-up of (35.6 +/- 19.0) months, all patients with ICD implanted received at least one appropriate ICD shock. One patient died of ventricular fibrillation suddenly and one patient underwent heart transplantation for progressive biventricular heart failure during the drug therapy alone.</AbstractText>This study demonstrated the clinical and ECG features of the 39 ARVD/C Chinese patients. ICD provided life-saving protection by effectively terminating malignant arrhythmias, and the high recurrence of VT was the major problem of RFCA therapy.</AbstractText> |
6,602 | Pacing threshold testing induced ventricular fibrillation following acute rate control of atrial fibrillation. | A properly placed stimulus on the T-wave during ventricular repolarization can result in ventricular fibrillation (VF). Initiation of VF with pacing on T-wave is a rare event with a few reported cases in the literature. We present a unique case of induced VF attributed to a pacing stimulus on T-wave during ventricular pacing threshold testing of a permanent pacemaker.</AbstractText>A 64-year-old woman with persistent atrial fibrillation (AF) and a permanent pacemaker for tachycardia-bradycardia syndrome presented with symptomatic AF with rapid ventricular response. Acute rate control was achieved with intravenous diltiazem. During ventricular pacing threshold testing, noncapture occurred followed by a pacing spike on T-wave initiating VF. Cardiopulmonary resuscitation and defibrillation converted the rhythm to rate-controlled AF. An acute prolongation of the QT was noted and normalized within 12 hours. No antiarrhythmic medications were used. Postevent laboratory values were within normal limits. She was free of ischemia and an echocardiogram revealed normal left ventricular function. She recovered from the event and was discharged with rate-controlled AF. No further pacing-induced arrhythmias have occurred during follow-up pacemaker interrogation and 12-lead electrocardiograms continued to show normal QT intervals.</AbstractText>Pacemaker-induced VF is an extraordinarily rare complication of cardiac pacing. Alterations in ventricular repolarization with rapid slowing of the heart rate demonstrated by acute prolongation of QT intervals may play a role. This report should alert physicians to the possibility of QT prolongation and an increased risk of ventricular arrhythmias following acute rate control of AF.</AbstractText> |
6,603 | The effects of left ventricular diastolic function on natriuretic peptide levels after cardioversion of atrial fibrillation. | Diastolic heart failure often coexists with atrial fibrillation (AF). Elevated plasma levels of natriuretic peptides are the left ventricular (LV) marker of diastolic dysfunction.</AbstractText>To evaluate the influence of sinus rhythm restoration on ANP and BNP levels in patients with normal and impaired LV diastolic function.</AbstractText>The study included 42 patients (19 men, 23 women), aged 58.6 +/- 8.2 years with non-valvular persistent AF with preserved LV systolic function who were successfully converted to sinus rhythm by DC cardioversion (CV) and maintained sinus rhythm for at least 30 days. On day 30 following CV in patients with sinus rhythm, Doppler echocardiography was performed to assess LV diastolic function. ECG, echocardiography, ANP and BNP plasma level measurements were made at baseline 24 h before CV and 24 h as well as 30 days after CV.</AbstractText>The average ANP level in the whole study group during AF was 254.9 +/- 79.9 pg/ml and the average BNP level was 113.6 +/- 49.1 pg/ml. There was an evident decrease in ANP/BNP serum concentration in all the patients after successful DC cardioversion. Measured on the 30th day after CV, ANP and BNP levels were 153.2 +/- 67.9 pg/ml and 61.9 +/- 25.1 pg/ml respectively (p < 0.001). Thirty days after CV normal LV diastolic function was diagnosed in 15 patients and in 27 patients impaired diastolic function: 20 with impaired LV relaxation and 7 with impaired LV compliance. The extent of natriuretic peptides drop was dependent on the LV diastolic function, being more substantial in the subgroup with impaired LV diastolic function. In the subgroup with LV diastolic dysfunction the average ANP serum concentration measured 30 days after conversion was reduced by 111.2 +/- 93.9 pg/ml (37%) (p < 0.001) and BNP level was reduced by 67.5 +/- 36.0 pg/ml (46%) (p < 0.001). In patients with normal diastolic function sinus rhythm restoration significantly influenced ANP level, while having no relevant effect on BNP plasma concentration. The average ANP reduction in this subgroup was 64.4 +/- 71.8 pg/ml (by 38%) and BNP reduction was 11.4 +/- 16.7 pg/ml (by 23%) (NS).</AbstractText>The drop in ANP and BNP plasma concentrations after conversion to sinus rhythm in patients with AF depends on the LV diastolic function. Restoration of sinus rhythm is associated with improvement of the heart's haemodynamics, especially in patients with impaired LV diastolic function, which may be inferred from the more pronounced decrease of BNP level after DC cardioversion in this subgroup, as compared to that with normal LV function.</AbstractText> |
6,604 | Ventricular pacing thresholds following high-energy implantable cardioverter defibrillator shocks in integrated bipolar defibrillation systems. | Increased ventricular pacing thresholds have been observed following monophasic implantable cardioverter defibrillator (ICD) shocks.</AbstractText>To examine changes following high-energy biphasic shocks delivered by integrated bipolar ICD systems.</AbstractText>Ten episodes of ventricular fibrillation (VF) were induced at 10 min intervals in nine pigs with integrated ICD systems. After 10 s of each episode of VF, a 40 J biphasic shock was delivered, which successfully terminated VF (a total of 10 shocks). The bipolar pacing threshold at the right ventricular apex was measured before each shock and at 1 min intervals after each shock.</AbstractText>The mean pacing threshold was 0.029+/-0.059 muJ before the first shock and gradually increased to 0.14+/-0.10 muJ after the 10th shock.</AbstractText>It may be necessary to pace at a high-voltage output following biphasic shocks delivered by integrated bipolar ICD systems.</AbstractText> |
6,605 | Role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the management of atrial fibrillation. | Atrial fibrillation (AF) is the most common clinical arrhythmia, and is difficult to treat. Current treatment strategies are far from optimal. Antiarrhythmic drug therapy to maintain sinus rhythm is limited by inadequate efficacy and potentially serious side effects. New areas of research include targeting the AF substrate and examining whether drugs can produce atrial structural and/or electrophysiological remodelling, and whether this results in a reduction in AF burden. There are two approaches to the treatment of AF. The first approach is cardioversion and treatment with antiarrhythmic drugs to maintain sinus rhythm. The other approach is the use of rate-controlling drugs allowing AF to persist. In both approaches, the use of anticoagulant drugs is recommended. There is an increasing interest in novel therapeutic approaches that target AF-substrate development. Recent trials suggest that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor II blockers (ARBs) may be useful, particularly in patients with left ventricular hypertrophy, hypertension, chronic heart failure and left ventricular dysfunction. While experimental studies have shown that the pathogenic structural and electrical remodelling of the atria are prevented by inhibition of angiotensin II, the clinical potential and mechanisms of this approach are still under active investigation. The present article will discuss information pertaining to the mechanism of action and clinical use of ACEIs and ARBs in AF. It will also review the current data on the use of ACEIs and ARBs in a high-risk group of AF patients (heart failure, hypertensive with left ventricular hypertrophy, and myocardial infarction), together with the potential benefit of this class type of pharmacological therapy in direct current cardioversion and after radiofrequency catheter ablation. |
6,606 | Complete recovery from aneurysmal subarachnoid hemorrhage associated with out-of-hospital cardiopulmonary arrest. | Out-of-hospital cardiopulmonary arrest (OHCPA) because of aneurysmal subarachnoid hemorrhage (SAH) is almost always fatal, because devastating SAH causes OHCPA and the brain damage is aggravated by OHCPA. We report a rare case of a 63-year-old female patient who survived SAH-induced ventricular fibrillation OHCPA without neurologic sequelae. Early brain computed tomography scans were needed for the diagnosis, as most of SAH seemingly disappeared within 7 h after the onset and was associated with acute coronary syndrome-like findings. This case shows that even less severe SAH can cause ventricular fibrillation OHCPA and takotsubo cardiomyopathy, and that early diagnosis and appropriate treatment following immediate, successful resuscitation may lead to a surprisingly favorable outcome. |
6,607 | Closed-chest experimental porcine model of acute myocardial infarction-reperfusion. | Progress in cardiovascular regenerative medicine research requires the availability of appropriate experimental animal models that are as close to humans as feasible. Our objective was to assess the validity of a porcine endovascular model of myocardial infarction and reperfusion.</AbstractText>Fifteen domestic pigs (Large White race) were anesthetized and pre-medicated with amiodarone. Endovascular fluoroscopy-guided coronary procedures were performed to occlude the mid-left anterior descending artery using a coronary angioplasty balloon. Occlusion was confirmed by angiography and electrocardiography. After 75 min the balloon catheter system was withdrawn and the presence of reperfusion flow was verified. The animals were sacrificed after 1 and 2 weeks of follow-up, the hearts were explanted, and the extent of myocardial infarction with respect to the left ventricle was quantified.</AbstractText>Overall survival rate was 67%. Five animals died prematurely: 3 showing signs of heart failure, 1 had reperfusion failure (final TIMI flow grade 1) and 1 succumbed to acute stress. The most common adverse event was ventricular fibrillation (87% of the animals) and defibrillation was effective in all affected animals. The extent of myocardial infarct in the animals followed-up for 1 and 2 weeks was similar (20.4+/-4.3% vs. 20.9+/-2.8%, respectively; p=0.8) but was significantly greater in the animals that died prematurely (29.5+/-3.6%, p=0.02).</AbstractText>The endovascular porcine model we have explored constitutes a feasible and reproducible alternative for the evaluation of human myocardial infarction and reperfusion.</AbstractText> |
6,608 | Prevalence and prediction of left atrial thrombus in patients with a recent cerebral ischemic event, who are in sinus rhythm: a single-center experience. | Left atrial thrombus (LAT) is frequently present in patients with cerebral ischemic events (CIE) who are in atrial fibrillation. The prevalence and predictor of LAT in patients who are in sinus rhythm (SR) is unclear.</AbstractText>To determine the prevalence and identify predictors of LAT formation in patients with CIE who are in SR.</AbstractText>Consecutive patients with CIE who are in SR were evaluated by transesophageal echocardiography (TEE) from July 2000 to August 2001. Patient demographics including cerebrovascular risk factors were recorded.</AbstractText>LAT was present in 5.5%. Left ventricular systolic dysfunction (LVSD) was present in 25 (10%). Patients' mean age was 59 +/- 14 years and 119 (50%) were male. In the univariate analysis, LAT was associated with LVSD (odds ratio [OR] 9.24, 95% confidence interval [CI] 2.8; 10.3) and male patients (OR 4.56, 95% CI: 1.6, 12.6) who had coronary artery disease (OR 3.4, 95% CI: 1.3, 8.4). In the multivariate analysis, LVSD (OR 10.6, CI 2.2-51.6) strongly predicted the development of LAT.</AbstractText>LAT is not uncommon in patients CIE, who are in sinus rhythm, especially those with poor left ventricular functions. TEE should be considered in patients with CIE and LVSD for early detection and treatment of LAT.</AbstractText> |
6,609 | [Circumferential pulmonary vein with additional linear ablation for persistent and permanent atrial]. | To investigate the safety and efficacy of circumferential pulmonary vein with additional linear ablation in treatment of persistent and permanent atrial fibrillation (AF), and to identify possible predictors of recurrence of AF.</AbstractText>The clinical data of 127 patients with persistent and permanent AF who had undergone circumferential pulmonary vein with additional linear ablation from January 2006 to December 2006 in multiple electrophysiological centers were collected, success rate and recurrence rate, cardiac function and atrial arrhythmias after ablation, and complications were analyzed. The relationship between the recurrent AF and clinical and echocardiographic variables was investigated.</AbstractText>A mean follow-up of 9 +/- 4 months showed that the success rate and recurrence rate were 68.5% and 31.5% respectively. After, both the left atrium diameter, left ventricular end diastole diameter, and left ventricular ejection fraction of the patients with successful ablation were (41 +/- 8) mm, (49 +/- 7) mm, and (61 +/- 8)% respectively, all not significantly different from those before ablation [(43 +/- 7) mm, (48 +/- 6) mm, and (62 +/- 10)% respectively, all P > 0.05]. After ablation the episodes of atrial tachyarrhythmias and atrial premature beat significantly increased (P < 0.05 and P < 0.01). The only complication was ecchymoma that occurred in 3 patients (2.4%). Female gender and left atrium enlargement were risk factors of recurrent AF (P < 0.05 and P < 0.05).</AbstractText>Circumferential pulmonary vein with additional linear ablation is a safe and moderately effective treatment for persistent and permanent atrial fibrillation.</AbstractText> |
6,610 | Intravenous diltiazem is superior to intravenous amiodarone or digoxin for achieving ventricular rate control in patients with acute uncomplicated atrial fibrillation. | To compare the clinical efficacy of intravenous diltiazem, digoxin, and amiodarone for acute ventricular rate (VR) control in patients with acute symptomatic atrial fibrillation (AF) necessitating hospitalization.</AbstractText>Randomized control trial.</AbstractText>Acute emergency medical admission unit in a regional teaching hospital in Hong Kong.</AbstractText>One hundred fifty adult patients with acute AF and rapid VR (>120 bpm).</AbstractText>Patients were randomly assigned in 1:1:1 ratio to receive intravenous diltiazem, digoxin, or amiodarone for VR control.</AbstractText>The primary end point was sustained VR control (<90 bpm) within 24 hours; the secondary end points included AF symptom improvement and length of hospitalization. At 24 hours, VR control was achieved in 119 of 150 patients (79%). The time to VR control was significantly shorter among patients in the diltiazem group (log-rank test, p < 0.0001) with the percentage of patients who achieved VR control being higher in the diltiazem group (90%) than the digoxin group (74%) and the amiodarone group (74%). The median time to VR control was significantly shorter in the diltiazem group (3 hours, 1-21 hours) compared with the digoxin (6 hours, 3-15 hours, p < 0.001) and amiodarone groups (7 hours, 1-18 hours, p = 0.003). Furthermore, patients in the diltiazem group persistently had the lowest mean VR after the first hour of drug administration compared with the other two groups (p < 0.05). The diltiazem group had the largest reduction in AF symptom frequency score and severity score (p < 0.0001). In addition, length of hospital stay was significantly shorter in the diltiazem group (3.9 +/- 1.6 days) compared with digoxin (4.7 +/- 2.1 days, p = 0.023) and amiodarone groups (4.7 +/- 2.2 days, p = 0.038).</AbstractText>As compared with digoxin and amiodarone, intravenous diltiazem was safe and effective in achieving VR control to improve symptoms and to reduce hospital stay in patients with acute AF.</AbstractText> |
6,611 | Hypothermia-treated cardiac arrest patients with good neurological outcome differ early in quantitative variables of EEG suppression and epileptiform activity. | To evaluate electroencephalogram-derived quantitative variables after out-of-hospital cardiac arrest.</AbstractText>Prospective study.</AbstractText>University hospital intensive care unit.</AbstractText>Thirty comatose adult patients resuscitated from a witnessed out-of-hospital ventricular fibrillation cardiac arrest and treated with induced hypothermia (33 degrees C) for 24 hrs.</AbstractText>None.</AbstractText>Electroencephalography was registered from the arrival at the intensive care unit until the patient was extubated or transferred to the ward, or 5 days had elapsed from cardiac arrest. Burst-suppression ratio, response entropy, state entropy, and wavelet subband entropy were derived. Serum neuron-specific enolase and protein 100B were measured. The Pulsatility Index of Transcranial Doppler Ultrasonography was used to estimate cerebral blood flow velocity. The Glasgow-Pittsburgh Cerebral Performance Categories was used to assess the neurologic outcome during 6 mos after cardiac arrest. Twenty patients had Cerebral Performance Categories of 1 to 2, one patient had a Cerebral Performance Categories of 3, and nine patients had died (Cerebral Performance Categories of 5). Burst-suppression ratio, response entropy, and state entropy already differed between good (Cerebral Performance Categories 1-2) and poor (Cerebral Performance Categories 3-5) outcome groups (p = .011, p = .011, p = .008) during the first 24 hrs after cardiac arrest. Wavelet subband entropy was higher in the good outcome group between 24 and 48 hrs after cardiac arrest (p = .050). All patients with status epilepticus died, and their wavelet subband entropy values were lower (p = .022). Protein 100B was lower in the good outcome group on arrival at ICU (p = .010). After hypothermia treatment, neuron-specific enolase and protein 100B values were lower (p = .002 for both) in the good outcome group. The Pulsatility Index was also lower in the good outcome group (p = .004).</AbstractText>Quantitative electroencephalographic variables may be used to differentiate patients with good neurologic outcomes from those with poor outcomes after out-of-hospital cardiac arrest. The predictive values need to be determined in a larger, separate group of patients.</AbstractText> |
6,612 | Management of cardiac arrest caused by coronary artery spasm: epinephrine/adrenaline versus nitrates. | Cardiopulmonary resuscitation guidelines imply the use of epinephrine/adrenaline during cardiopulmonary arrest. However, in cardiac arrest situations resulting from coronary artery spasm (CAS), the use of epinephrine/adrenaline could be deleterious.</AbstractText>A 49-year-old patient underwent an emergency coronarography with an attempt to stent the coronary arteries. Radiologic imaging revealed a positive methylergonovine maleate (Methergine, Novartis Pharmaceuticals, East Hanover, NJ) test, with subocclusive CAS in several coronary vessels leading to electromechanical dissociation. Cardiopulmonary resuscitation was performed, and intracoronary boluses of isosorbide dinitrate were given to treat CAS. Epinephrine/adrenaline was not administered during resuscitation. Spontaneous circulation was obtained after cardioversion for ventricular fibrillation, and the patient progressively regained consciousness.</AbstractText>Resuscitation guidelines do not specify the use of trinitrate derivatives in cardiac arrest situations caused by CAS. The pros and cons of the use of nitrates and epinephrine/adrenaline during cardiac arrest caused by CAS are analyzed in this case report.</AbstractText> |
6,613 | Should aldosterone blockade be used beyond current indications in heart failure? | Aldosterone receptor antagonists (ARAs) are becoming important supplementary options in the pharmacologic treatment of congestive heart failure (CHF), and the indication for ARAs continues to grow. Aldosterone is a stimulator of myocardial fibrosis, causing progression of CHF and serving as an important factor in the pathogenesis of diastolic heart failure (ie, heart failure with normal ejection fraction). The beneficial effects of ARAs have already been demonstrated in patients with severe CHF and patients with symptoms of CHF and left ventricular dysfunction early after myocardial infarction. ARAs may also be important in mild to moderate CHF, but current evidence has not been convincing. More is to be expected from the potential role of ARAs in heart failure with normal ejection fraction and perhaps in atrial fibrillation. It is hoped that the results of large randomized clinical trials further elucidate the indications of ARAs beyond current guidelines. |
6,614 | Intra-left atrial mechanical delay detected by tissue Doppler echocardiography can be a useful marker for paroxysmal atrial fibrillation. | There are some clinical and echocardiographic parameters to predict paroxysmal atrial fibrillation (PAF), but more sensitive predictors are needed. Tissue Doppler imaging may be a sensitive method for this purpose.</AbstractText>Thirty-four patients with PAF and 31 control subjects were studied. Time intervals from the beginning of P-wave to beginning of A-wave from lateral and septal mitral and right ventricular tricuspid annuli in tissue Doppler imaging were recorded. The differences between these intervals gave the mechanical delays between/within the corresponding atria.</AbstractText>There were no differences between groups with regard to age. PAF patients were found to have increased left atrial dimension and intra-left atrial mechanical delay. Twenty-five milliseconds was calculated as cutoff value to predict PAF. P-wave dispersion was found to be increased in PAF.</AbstractText>This study shows an increase in intra-left atrial mechanical delay in PAF patients. This method can be used as an early marker to detect PAF.</AbstractText> |
6,615 | Induced hypothermia after out-of-hospital cardiac arrest: one hospital's experience. | Induced mild hypothermia has been shown to reduce in-hospital mortality and to improve neurological outcome in patients who remain comatose after out-ofhospital cardiac arrest (OHCA). We conducted a retrospective audit to assess whether induced hypothermia had been successfully incorporated into routine care at our hospital, and whether this improved patient outcomes.</AbstractText>Retrospective audit of patients admitted to a Level III intensive care unit, Melbourne, Victoria, between 2001 and 2007. Patients treated with therapeutic hypothermia (introduced in 2004) were compared with those who did not receive this therapy.</AbstractText>Patients admitted to the ICU comatose after OHCA with a presumed cardiac cause.</AbstractText>Induction of mild hypothermia by rapid infusion of cold intravenous fluids.</AbstractText>Hospital survival and neurological outcome at hospital discharge; time taken for core temperature to reach the target range (33 degrees +/-0.5 degrees C) and time temperature was maintained, determined from patient ICU records.</AbstractText>123 patients were admitted comatose after OHCA with a presumed cardiac cause: 75 were admitted after induced hypothermia was introduced into routine care and received this treatment; and 48 admitted earlier did not receive the treatment. For patients with the initial rhythm of ventricular fibrillation (VF) or unstable ventricular tachycardia (uVT), treatment with induced hypothermia was associated with a higher hospital survival rate (P=0.03; odds ratio [OR], 2.51; 95% CI, 1.06-5.95) and better neurological outcome (P=0.02; OR, 2.85; 95% CI, 1.19-6.86). In 90% of patients treated with induced hypothermia, core temperature reached the target range within 6 hours of hospital presentation; mean duration of in-hospital cooling was 25.5 hours (SD, 2.9 hours).</AbstractText>We found that induced hypothermia can be incorporated into routine care of patients admitted to an ICU after OHCA. For patients with an initial rhythm of VF or uVT, this seems to have significantly improved hospital survival and neurological outcome. We also found that rapid infusion of cold intravenous fluids was effective for inducing hypothermia.</AbstractText> |
6,616 | [Clinical analysis of inappropriate shock of implantable cardioverter defibrillators]. | Implantable cardioverter defibrillator (ICD) can effectively treat life-threatening ventricular arrhythmias. The most common side effect is inappropriate discharge. This study analyzes the incidence and causes of inappropriate discharges of ICD in our hospital.</AbstractText>Forty-three patients implanted with ICD in our hospital from November 2001 to October 2007 were involved in our study. Patients were followed-up regularly. All episodes recorded and stored in the ICD were analyzed.</AbstractText>Seven of the 43 patients underwent ninety-six inappropriate discharges. Inappropriate discharges in six patients were caused by supraventricular tachyarrhythmias (SVT). In one patient the discharge was caused by noise. Most inappropriate discharges occurred in the first year after implantation. The history of atrial fibrillation before implantation is an independent predictor of inappropriate discharges.</AbstractText>The incidence of inappropriate discharge is 16.3% in our study and the most common cause is SVT. Most inappropriate discharges occur in the first year after implantation. Patients with atrial fibrillation history have a higher risk of inappropriate discharges.</AbstractText> |
6,617 | [A clinical study on the diagnostic criteria of multiple organ dysfunction syndrome]. | To develop diagnostic criteria of multiple organ dysfunction syndrome (MODS) by a prospective and multi-center clinical investigation.</AbstractText>The data of 1087 MODS cases obtained from ICU of 37 hospitals from March 2002 to January 2005 in 11 provinces in China were analyzed in order to derive the diagnostic criteria of MODS.</AbstractText>This MODS diagnostic criteria involved 7 organs. To diagnose MODS, the original cause of MODS should be identified, then there should be two or more organs showing signs of dysfunction. The criteria for organ dysfunction were as follows. (1) Cardiovascular system: SBP < 90 mm Hg (1 mm Hg = 0.133 kPa), MAP < 70 mm Hg, signs of shock, ventricular tachycardia, ventricular fibrillation, or myocardial infarction; (2) Respiratory system: oxygenation index < 300 mm Hg; (3) Nervous system: indifference, restlessness, lethargy, light coma, or deep coma, Glasgow score < or = 14; (4) Blood system: PLT < 100 x 10(9)/L; CT, APTT, and PT prolonged or shortened; positive plasma protamine paracoagulation; (5) Liver: TBIL > 20. 5 micromol/L, ALB < 28 g/L; (6) Kidney: Cr > 123.8 micromol/L, urinary volume < 500 ml/24 h; (7) Gastro-intestine: bowel sounds decreased or disappeared; retention in the stomach, or positive occult blood feces with dark stools or haematemesis; intraabdominal pressure (intravesical pressure) > or = 11 cm H2O (1 cm H2O = 0.098 kPa). Any organ function met with one of the above conditions was considered to have dysfunction.</AbstractText>This diagnostic criterion of multiple organ dysfunction syndrome has been developed by this research, but it needs to accumulate experience by clinical practice and to revise the diagnosis criteria.</AbstractText> |
6,618 | Lightning induced atrial fibrillation. | Atrial fibrillation (AF) is a common arrhythmia that occurs in paroxysmal and persistent forms. It occurs in varied situations but lightning induced AF is extremely rare. Here is a case which reverted to sinus rhythm spontaneously. This 37-year-old man without any underlying heart disease had new onset AF after being struck by a lightning. Oral Metoprolol alone was given to control ventricular rate. Spontaneous reversion to sinus rhythm within 36 hours is in favor of new onset lightning induced AF. |
6,619 | Role of the His-Purkinje system in the genesis of cardiac arrhythmia. | Although a plethora of earlier studies focused on the histology and action potential characteristics of Purkinje fibers, only recently has the His-Purkinje system been found to play a major role in the genesis of cardiac arrhythmias. The anatomic complexity of the left ventricular conduction system appears to favor reentrant arrhythmias in both diseased and healthy hearts. Macroreentrant circuits between the right and left bundles as well as between the left ventricular fascicles are amenable to cure by ablative techniques. Similarly, fascicular tachycardias occurring in individuals without structural cardiac disease appear to involve macroreentrant circuits between fascicles and associated strands (false tendons?). Exciting newer discoveries strongly implicate the Purkinje system as the cause of ventricular arrhythmias in patients with short-coupled premature ventricular complexes and in those with catecholaminergic polymorphous ventricular tachycardia. The role of the His-Purkinje system in the genesis and maintenance of ventricular fibrillation is yet another frontier for fertile investigation. A rich variety of cardiac arrhythmias appears to involve the ventricular specialized conduction system and may be amenable to ablative therapy. |
6,620 | Spectral analysis of sustained and non-sustained ventricular fibrillation in patients with an implantable cardioverter-defibrillator. | The mechanisms responsible for the maintenance and termination of ventricular fibrillation (VF) are poorly understood. The aim of this study was to compare the spectral characteristics of the electrical signal during sustained and non-sustained VF in patients with an implantable cardioverter-defibrillator. The study included 51 patients who had had at least one episode of sustained VF (i.e., duration >5 s and requiring shock administration) and non-sustained VF (i.e., duration >3 s and spontaneously terminated) that were recorded by the device set in a unipolar configuration. Spectral analysis of the first 3 s of each episode was performed. The dominant frequency was higher in sustained VF (4.6+/-0.7 Hz) than in non-sustained VF (4.3+/-0.6 Hz; P=.01), while the other parameters were similar. Although the spectral characteristics of sustained and non-sustained VF were similar, differences were observed during the first 3 s that could be used in algorithms for the early detection of non-sustained VF. |
6,621 | QRS duration and early hemodynamic instability after coronary revascularization surgery. | The duration of the QRS interval measured by ECG is a marker of ventricular dysfunction and indicates a poor prognosis. Its value in patients undergoing coronary revascularization surgery has not been established.</AbstractText>The study involved 203 consecutive patients (age 64+/-9 years, 74% male) scheduled for elective coronary surgery. The maximum QRS duration measured on a preoperative 12-lead ECG was recorded. Hemodynamic instability was defined as the occurrence of cardiac death, heart failure, or a need for intravenous inotropic drugs or intra-aortic balloon counterpulsation during the postoperative period.</AbstractText>The occurrence of hemodynamic instability (n=94, 46%) was associated with a longer preoperative QRS duration (97.5+/-21.14 ms vs 88.5+/-16.9 ms; P=.001). The QRS duration was also longer in patients who developed heart failure (n=23; 104.3+/-22.9 ms vs. 91.1+/-18.5 ms; P=.002), needed inotropic drugs (n=77; 96.5+/-20.5 ms vs. 90.1+/-18.2 ms; P=.007) or developed postoperative atrial fibrillation (n=58; 98.2+/-23.8 ms vs. 90.4+/-17.0 ms; P=.018). Bundle branch block was associated with a greater need for intra-aortic balloon counterpulsation (29% vs 12%; P=.012) or inotropic drugs (58% vs 35%; P=.014) and a higher incidence of hemodynamic instability (69% vs 42%; P=.006). Multivariate analysis identified the following independent predictors of hemodynamic instability: QRS duration (adjusted odds ratio [OR] per 10 ms=1.49; 95% confidence interval [CI], 1.11-2; P=.007), the lack of an arterial graft (OR=3.6; 95% CI, 1.14-11.6; P=.029) and extracorporeal circulation time (OR per min=1.013; 95% CI, 1.003-1.023; P=.013).</AbstractText>The intraventricular conduction delay, or QRS duration, was associated with a higher risk of postoperative hemodynamic instability following coronary surgery.</AbstractText> |
6,622 | Atrial Fibrillation Complicating Congestive Heart Failure: Electrophysiological Aspects And Its Deleterious Effect On Cardiac Resynchronization Therapy. | More successful recognition and treatment of cardiovascular risk factors and diseases continues to decrease mortality and increase the proportion of elderly population. Therefore, there are more people with increased risk of developing heart failure and atrial fibrillation in the course of their lives. Atrial fibrillation (AF) can complicate the course of congestive heart failure (HF) leading to acute pulmonary edema. The prevalence of AF, in patients with heart failure, increases with the severity of the disease, reaching up to 40% in advanced cases. In these HF patients, AF is an independent predictor of morbidity and mortality increasing the risk of death and hospitalization. Despite the excellent results obtained with different drugs, the optimal medical treatment can fail in the intention to improve symptoms and quality of life of patients with severe HF. Thus, the necessity to use cardiac devices emerges facing the failure of optimal medical treatment in order to achieve hemodynamic improvement and correction of the physiopathological alterations. Cardiac resynchronization therapy (CRT) can reduce the interventricular and intraventricular mechanical dissynchrony in HF patients. It has been shown that CRT increases the left ventricular filling time, decreases septal dissynchrony, mitral regurgitation, and left ventricular volumes allowing a hemodynamic improvement. However, the development of AF in this setting can avoid the beneficial effects of CRT. Therefore, this manuscript will review the available data on this topic, the electrophysiological aspects of AF, to determine what can be done in the event of an AF complicating congestive HF in CRT patients. |
6,623 | Electrocardiographic abnormalities and ventricular tachyarrhythmias after myocardial infarction. | To assess the association of electrocardiographic repolarization and depolarization patterns to vulnerability to ventricular tachyarrhythmias.</AbstractText>In the present case-control study, a 12-lead ECG, signal-averaged ECG (SAECG), T-wave and QRS morphology, and T-wave alternans (TWA) were analyzed in post-MI patients with and without documented sustained ventricular tachycardia (VT) or fibrillation (VF) (VT/VF group, n=40, Non-VT/VF group, n=37, respectively) and healthy subjects (n=41).</AbstractText>The QRS complex duration, measured from standard ECG (128 +/- 32 ms vs. 102 +/- 21 ms, p<0.001) or SAECG (125 +/- 25 ms vs. 99 +/- 20 ms, p<0.001), was significantly longer in the VT/VF than Non-VT/VF group. Several T-wave morphology variables, e.g., the total cosine of the angle between the main vectors of T-wave and QRS loops (TCRT), were different in the VT/VF (-0.13 +/- 0.58) and Non-VT/VF group (-0.11 +/- 0.48) compared to the healthy controls (0.47 +/- 0.50, p<0.001). However, there were no significant differences in any of the T-wave morphology variables including TWA between the two post-MI groups.</AbstractText>Abnormalities in ventricular depolarization are more common among post-MI patients with prior VT/VF than in those without documented ventricular tachyarrhythmias. Abnormal T-wave morphology and TWA seem to reflect the heart disease rather than specifically vulnerability to VT/VF.</AbstractText> |
6,624 | Sustained ventricular arrhythmias in unstable angina patients: results of the ARIAM database. | The aim of this study was to investigate patients with unstable angina (UA) and the predictive factors of these arrhythmias and to determine whether this complication behaves as an independent variable with regard to mortality, increased length of stay in an ICU/CCU, and the performance of percutaneous coronary intervention (PCI).</AbstractText><AbstractText Label="MATERIAL/METHODS" NlmCategory="METHODS">The retrospective cohort study included all patients diagnosed with UA and included in the Spanish "ARIAM" database between June 1996 and December 2005. Univariate and multivariate analyses were performed to evaluate the factors associated with these arrhythmias. 17,616 patients were included.</AbstractText>Sustained ventricular tachycardia (SVT) occurred in 0.5%. The factors associated with its development were age, cardiogenic shock, and non-sustained ventricular tachycardia. SVT was associated with mortality (adjusted OR: 9.836, 95%CI: 1.81-53.33). Ventricular fibrillation (VF) occurred in 1%. In the multivariate study the variables that persistently associated independently with the development of VF were gender, Killip class, and high degree atrioventricular block (HDAVB). VF was associated with higher mortality (27.1% vs. 0.9%). Nevertheless, VF was not seen to be a variable independently associated with mortality in UA patients. Only VF was an independent variable in length of stay (adjusted OR: 2.059, 95%CI: 1.175-3.609). Neither SVT nor VF were independent variables associated with PCI.</AbstractText>Patients with UA complicated by SVT or VF represent a special high-risk subgroup with poor prognosis, which could lead to their being stratified towards a poor prognosis subgroup.</AbstractText> |
6,625 | Carvedilol ameliorates the decreases in connexin 43 and ventricular fibrillation threshold in rats with myocardial infarction. | Connexin 43 (Cx43) is the most prominent connexin in the mammalian ventricular myocardium and forms gap junctions that are essential for normal conduction of action potential. Carvedilol, a nonselective beta-blocker, is widely used to prevent ventricular arrhythmias after myocardial infarction (MI). Here, we examined the effect of carvedilol on the expression of Cx43 protein and ventricular fibrillation threshold (VFT) using a rat MI model. VFT is defined as the lowest voltage, at which ventricular fibrillation is induced by electrical stimulation. Adult male Wister rats were divided into sham-operated group (n = 20) and MI groups treated with intragastric administration of saline (control, n = 30) or carvedilol (2.5 mg/kg, n = 30) twice a day for 7 days immediately after ligation of the left coronary artery. Compared with sham group (100%), total Cx43 protein and phosphorylated Cx43 protein were decreased in the MI rats to 60 +/- 21% and 52 +/- 19% (both P < 0.05), respectively. Treatment with carvedilol prevented the MI-induced decrease in total and phosphorylated Cx43 levels (91 +/- 17% and 80 +/- 20%, both P < 0.05), respectively, which were similar to the levels of sham animals. Moreover, the MI rats exhibited a marked decrease in VFT compared with the sham group (7.2 +/- 1.30 vs. 13.0 +/- 2.12 V, P < 0.05), but the decrease was abolished by carvedilol (11.0 +/- 2.65 V). In conclusion, carvedilol might prevent the ischemia-induced ventricular arrhythmias by restoring Cx43 protein and VFT to the basal levels. |
6,626 | Therapeutic effect of {beta}-adrenoceptor blockers using a mouse model of dilated cardiomyopathy with a troponin mutation. | Extensive clinical studies have demonstrated that beta-adrenoceptor blocking agents (beta-blockers) are beneficial in the treatment of chronic heart failure, which is due to various aetiologies, including idiopathic dilated cardiomyopathy (DCM) and ischaemic heart disease. However, little is known about the therapeutic efficacy of beta-blockers in the treatment of the inherited form of DCM, of which causative mutations have recently been identified in various genes, including those encoding cardiac sarcomeric proteins. Using a mouse model of inherited DCM with a troponin mutation, we aim to study the treatment benefits of beta-blockers.</AbstractText>Three different types of beta-blockers, carvedilol, metoprolol, and atenolol, were orally administered to a knock-in mouse model of inherited DCM with a deletion mutation DeltaK210 in the cardiac troponin T gene (TNNT2). Therapeutic effects were examined on the basis of survival and myocardial remodelling. The lipophilic beta(1)-selective beta-blocker metoprolol was found to prevent cardiac dysfunction and remodelling and extend the survival of knock-in mice. Conversely, both the non-selective beta-blocker carvedilol and the hydrophilic beta(1)-selective beta-blocker atenolol had no beneficial effects on survival and myocardial remodelling in this mouse model of inherited DCM.</AbstractText>The highly lipophilic beta(1)-selective beta-blocker metoprolol, known to prevent ventricular fibrillation via central nervous system-mediated vagal activation, may be especially beneficial to DCM patients showing a family history of frequent sudden cardiac death, such as those with a deletion mutation DeltaK210 in the TNNT2 gene.</AbstractText> |
6,627 | [Management of atrial fibrillation in France: the observational FACTUEL study]. | To describe the management of patients with atrial fibrillation (AF) and to study consistency with guidelines on management of AF.</AbstractText>Observational study on a random sample of cardiologists from a French national database. Each cardiologist had to recruit the first five patients meeting inclusion criteria (patients diagnosed with AF between January 2004 and one month before inclusion and accepting the collection of their medical data).</AbstractText>Between December 2006 and January 2207, 1789 patients aged 71 on average have been recruited by 481 cardiologists. Fifty-one percent were diagnosed with paroxysmal, 15% with persistent and 33% with permanent AF. Restoration of sinus rhythm was preferred in forms considered as paroxysmal or persistent forms whereas control of the ventricular rate was more frequent in AF considered as permanent. Overall, therapeutic guidelines are applied in practice, despite a frequent use of amiodarone in patients with no associated heart disease. Prevention of thromboembolism was observed in 88% of the patients.</AbstractText>FACTUEL is the biggest observational study on AF ever conducted in France. The therapeutic strategies used by the cardiologists are consistent with the objectives of preventing thromboembolism and controlling heart rhythm and/or rate. In most cases, the treatment used is consistent with the therapeutic guidelines.</AbstractText> |
6,628 | Vascular Ehlers-Danlos syndrome--all three coronary artery spontaneous dissections. | Vascular Ehlers-Danlos syndrome is an inherited connective-tissue disorder causing arterial and gastrointestinal fragility and spontaneous rupture of the large arteries, uterus, or bowel. Among arterial dissections and ruptures, spontaneous coronary artery dissection is extremely rare in this disorder. The specific therapeutic strategy for this disorder and its complications has not yet been established. In this report, we describe a 33-year-old woman with all three coronary artery spontaneous dissections, resulting in cardiogenic shock and therapy-resistant ventricular fibrillation. We could successfully complete revascularization of all three coronary arteries and terminate the life-threatening arrhythmia. Biochemical findings finally revealed a point mutation in the COL3A1 gene, consistent with a diagnosis of vascular Ehlers-Danlos syndrome. To the best of our knowledge, this is the first case of vascular Ehlers-Danlos syndrome causing all three coronary artery spontaneous dissections. Our case also suggests that, from vascular fragility even if it is spontaneous coronary dissection, physicians always consider connective-tissue disorders as a differential diagnosis at an early stage even though that would be a first complication, and percutaneous coronary intervention with stenting using intravascular ultrasound could be a strategic option for even repeated and fatal spontaneous coronary artery dissections in vascular Ehlers-Danlos syndrome. |
6,629 | Utility of tissue Doppler imaging to predict exercise capacity in hypertrophic cardiomyopathy: comparison with B-type natriuretic peptide. | Recent reports suggest that left ventricular diastolic function assessed by tissue Doppler imaging (TDI) and plasma B-type natriuretic peptide (BNP) levels can relate to functional status in patients with hypertrophic cardiomyopathy (HCM). However, it is unclear which is more useful to predict the exercise capacity in HCM patients without systolic impairment and/or atrial fibrillation, TDI or BNP levels.</AbstractText>The present study directly compared the clinical relevance of assessing diastolic function using TDI and measuring the plasma BNP level in patients with HCM.</AbstractText>We evaluated diastolic function using TDI as well as plasma BNP levels in 31 patients (52.2+/-16.9 years of age; 20 males) with HCM and examined the relationship of these values to exercise capacity (peak O(2) consumption (VO(2))) measured by cardiopulmonary exercise tests.</AbstractText>Average peak VO(2) was 18.5+/-4.7 ml/(kg min). Although the E/A ratio by transmitral flow was not correlated with peak VO(2), the lateral E/E(a) ratio assessed by TDI was significantly correlated with peak VO(2) (r=-0.52, p=0.003). On the other hand, plasma BNP level was not significantly related to peak VO(2) but NYHA class.</AbstractText>Assessment of diastolic function using TDI, not plasma BNP levels, is more useful for predicting objective exercise capacity in HCM patients without systolic impairment and/or atrial fibrillation.</AbstractText> |
6,630 | Recurrent ventricular fibrillation due to coronary artery spasm immediately after ascending aorta replacement. | Coronary artery spasm (CAS) is a dangerous complication during cardiac surgery, causing arduous weaning of extracorporeal circulation (ECC) and myocardial tissue loss with consequent left and right ventricular dysfunctions. We describe the case of a 67-year-old man with hypertension and smoking habit, with ECG evidence of lateral myocardial ischemia without symptoms. On this basis, he was investigated with scintigraphy, which confirmed an anterior-lateral area of reversible ischemia and, subsequently, with angiography, which revealed just mild lesion (50%) of diagonal ramus associated with ascending aorta aneurysm: no sign of CAS was detected. Left ventricular function was normal, with mild hypokinesia of the apical segments and trivial aortic regurgitation. The patient underwent ascending aorta replacement with arduous ECC weaning due to CAS: exclusively, the use of intravenous administration of diltiazem led to the solution of this complication. Even if medical therapy is generally efficacious for this complication, the diagnosis is very complicated when it appears in the operating room immediately after cardiac surgery because of the lack of any useful device. The difficulty of diagnosis in the operating room might compromise patient outcome. In our opinion, when ECC weaning is complicated by several episodes of malignant tachyarrhythmia and there is the suspicion of underlying ischemic cause without other obvious causes, CAS must be considered and empirical therapy with calcium channel blockers should be used. |
6,631 | Cardiac resynchronization therapy with and without implantable cardioverter-defibrillator. | Cardiac resynchronization therapy (CRT) is recommended to reduce morbidity and mortality in patients with New York Heart Association class III/IV, who are symptomatic despite optimal medical therapy, and who had a reduced left ventricle (LV) ejection fraction and electrical dyssynchrony. The effects of CRT are reflected mainly by the degree and location of dyssynchrony and by working in insertion of optimal LV lead site. Echocardiography and Doppler echocardiography are considered to be good tools to measure LV dyssynchrony directly. However, the large randomized trials have shown that no single echocardiographic measure of dyssynchrony is recommended to improve patient selection for CRT beyond current guidelines. There were several unsolved issues on CRT, such as patient selection, electrical or electromechanical dyssynchrony criteria to patients for CRT, indication of patients with a narrow or slightly prolonged QRS width, indication of patients with atrial fibrillation, and indication of patients with mild heart failure or asymptomatic LV dysfunction, and device selection; CRT alone (CRT-P) or CRT in combination with implantable cardioverter therapy (CRT-D). This review paper summarized the concept of therapy, the current evidence regarding the indications, effectiveness and safety of CRT-P and CRT-D in patients with LV dysfunction, and unsolved issues. |
6,632 | Usefulness of cardiac magnetic resonance in assessing the risk of ventricular arrhythmias and sudden death in patients with hypertrophic cardiomyopathy. | To assess the relationship between cardiovascular magnetic resonance (CMR) parameters and both spontaneous ventricular tachycardia (VT) and risk of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) patients.</AbstractText>One hundred and eight consecutive HCM patients (mean age 42 +/- 15 years, 76% males) underwent CMR evaluation and risk assessment. Delayed contrast enhancement (DCE) was quantified with a specifically designed score. Endpoints were either the presence of clinical VT/ventricular fibrillation (VF) or of acknowledged risk factors for SCD. Compared to patients without arrhythmia, those with VT/VF (n = 33) had a higher DCE score [median 8 (2-13) vs. 11 (6-20); P = 0.01]; DCE score was also the only independent predictor of VT/VF in the multivariable model. DCE score [median 6 (1-10.5) vs. 12 (6-18); P = 0.001], mean and maximal left ventricular (LV) wall thickness (MaxLVWT), as well as LV mass index were significantly greater among patients at risk for SCD (n = 51) compared with the remaining 57 patients at low risk. DCE score and MaxLVWT were independent predictors of SCD risk.</AbstractText>In HCM patients several CMR parameters are associated with risk for SCD. A semi-quantitative index of DCE is a significant multivariable predictor of both clinical VT/VF and of risk for SCD and may contribute to risk assessment in borderline or controversial cases.</AbstractText> |
6,633 | Presenting rhythm in sudden deaths temporally proximate to discharge of TASER conducted electrical weapons. | Sudden deaths proximate to use of conducted electrical weapons (CEWs) have been attributed to cardiac electrical stimulation. The rhythm in death caused by rapid, cardiac electrical stimulation usually is ventricular fibrillation (VF); electrical stimulation has not been reported to cause asystole or pulseless electrical activity (PEA). The authors studied the presenting rhythms in sudden deaths temporally proximate to use of TASER CEWs to estimate the likelihood that these deaths could be caused by cardiac electrical stimulation.</AbstractText>This was a retrospective review of CEW-associated, nontraumatic sudden deaths from 2001 to 2008. Emergency medical services (EMS), autopsy, and law enforcement reports were requested and analyzed. Subjects were included if they collapsed within 15 minutes of CEW discharge and the first cardiac arrest rhythm was reported.</AbstractText>Records for 200 cases were received. The presenting rhythm was reported for 56 of 118 subjects who collapsed within 15 minutes (47%). The rhythm was VF in four subjects (7%; 95% confidence interval [CI] = 3% to 17%) and bradycardia-asystole or PEA in 52 subjects (93%; 95% CI = 83% to 97%). None of the eight subjects who collapsed during electrocardiogram (ECG) monitoring had VF. Only one subject (2%) collapsed immediately after CEW discharge. This was the only death typical of electrically induced VF (2%, 95% CI = 0% to 9%). An additional 4 subjects (7%) collapsed within 1 minute, and the remaining 51 subjects (91%) collapsed more than 1 minute later. The time from collapse to first recorded rhythm was 3 minutes or less in 35 subjects (62%) and 5 minutes or less in 43 subjects (77%).</AbstractText>In sudden deaths proximate to CEW discharge, immediate collapse is unusual, and VF is an uncommon VF presenting rhythm. Within study limitations, including selection bias and the possibility that VF terminated before the presenting rhythm was recorded, these data do not support electrically induced VF as a common mechanism of these sudden deaths.</AbstractText> |
6,634 | Usefulness of heart rate variability as a predictor of sudden cardiac death in muscular dystrophies. | Sudden cardiac death, or cardiac arrest, is a major health problem, causing about 166,200 deaths each year among adults in the United States. It may be caused by almost all known heart diseases. Most cardiac arrests occur when the diseased heart begins to exhibit rapid and/or chaotic activity, such as ventricular tachycardia or fibrillation. Some are due to extreme slowing of the heart. All these events are called life-threatening arrhythmias. Arrhythmogenic cardiomyopathy is a frequent feature in several muscular dystrophies with a potential risk of cardiac sudden death. Among the measures able to predict the propensity to develop life-threatening arrhythmias, heart rate variability is an accepted non invasive measurement of cardiac autonomic modulation. The use of heart rate variability to measure the extent of changes in autonomic nervous system is an established risk stratification procedure in different diseases. In fact numerous studies have demonstrated the positive prognostic power of altered heart rate variability values to predict all-cause mortality, cardiac events, sudden cardiac death and heart transplantation. Usefulness of heart rate variability as a predictor of sudden cardiac death in muscular dystrophies has been reviewed. |
6,635 | Adenosine-induced ventricular asystole or rapid ventricular pacing to enhance three-dimensional rotational imaging during cardiac ablation procedures. | Rotational angiography with digital three-dimensional reconstruction (3DRA) allows per-procedural 3D imaging to facilitate cardiac ablation procedures. We developed a new approach that allows per-procedural 3D imaging of the atria and ventricles with a single C-arm rotation, combining higher 3D image quality with a lower contrast and radiation dose.</AbstractText>Forty patients underwent 3DRA of the left atrium (LA, n = 26), right atrium (RA, n = 11), left ventricle (LV, n = 2), or right ventricle (RV, n = 1) during ablation procedures performed under general anaesthesia. Contrast agent (60 +/- 12 mL) was diluted and injected directly in the chamber of interest, during adenosine-induced ventricular asystole (n = 31) or rapid RV pacing (n = 9, atrial imaging only) to reduce cardiac motion artefacts and enhance contrast opacification during rotational imaging. Reconstructed 3D data sets were graded according to predefined quality criteria (n = 40) and quantitatively compared with cardiac computed tomography (CT) (LA, n = 14). Adenosine-induced ventricular asystole and rapid pacing both allowed a sustained and homogeneous contrast opacification of target cardiac chambers, resulting in useful 3D data sets in 39 of 40 (98%) patients. Moreover, it was possible to achieve 'good' or 'optimal' 3D image quality in the majority of patients (adenosine: 61%, pacing 78%, P = 0.69). When compared with rapid pacing, the total elimination of cardiac motion artefacts with adenosine more frequently resulted in 'optimal' 3D image quality (42% vs. 11%, P = 0.01) and added the possibility for single-rotation 3D imaging of the ventricles. Quantitative analysis showed an excellent agreement between pulmonary vein diameters measured on cardiac CT and 3DRA images. Integration of 3DRA-based LA surfaces with real-time fluoroscopy was easy and highly accurate.</AbstractText>Adenosine-induced ventricular asystole or rapid ventricular pacing allow acquisition of 3DRA with an excellent direct contrast opacification of any cardiac chamber and a reduction of cardiac motion artefacts, resulting in high-quality per-procedural 3D imaging with a single C-arm rotation.</AbstractText> |
6,636 | Regionalization of postcardiac arrest care. | To discuss the concept and implementation of regionalized postcardiac arrest care.</AbstractText>American Heart Association guidelines call for therapeutic hypothermia in patients who have return of spontaneous circulation but remain comatose after out-of-hospital cardiac arrest due to ventricular fibrillation. The real and perceived technical challenges of inducing, maintaining, and monitoring postarrest patients who have received induced hypothermia have limited its widespread use. In addition, recent data suggest that emergency primary coronary intervention may benefit those victims of out-of-hospital cardiac arrest with return of spontaneous circulation. However, most community hospitals lack consistent 24-h a day emergency percutaneous coronary intervention capability. Therefore, despite showing efficacy in clinical trials, these therapies remain underutilized in clinical practice, thus limiting their widespread use. The concept of regionalized specialty care has been used successfully for other time-sensitive illnesses such as major trauma and acute stroke. Evidence extrapolated from the trauma and stroke literature suggests that such a system of care would be well tolerated, feasible, and would improve outcomes after out-of-hospital cardiac arrest.</AbstractText>It is feasible to implement a large system of care in which eligible postcardiac patients are triaged to centers capable of delivering standardized, state-of-the art postarrest care. Further research is warranted to determine the optimal design of such a system of care.</AbstractText> |
6,637 | Cardiopulmonary resuscitation in children. | To summarize recent advances in pediatric cardiopulmonary arrest prevention, resuscitation and postresuscitation management.</AbstractText>Pediatric cardiac arrest has traditionally been considered a futile medical condition with dismal outcomes. Data in the 21st century indicate that more than 25% of children treated for in-hospital cardiac arrests survive to hospital discharge and more than 10% of children older than 1 year treated for out-of-hospital cardiac arrests survive to hospital discharge. These data establish that children are more likely to survive to hospital discharge than adults after both in-hospital and out-of-hospital cardiac arrests. Before arrest, exciting new studies demonstrate that the implementation of in-hospital pediatric medical emergency teams is associated with significant decreases in cardiac arrest incidence and overall pediatric hospital mortality. During arrest, ventricular fibrillation or ventricular tachycardia, once thought to be rare in children, occurs during 25% of inhospital pediatric cardiac arrests and at least 7% of out-of-hospital pediatric cardiac arrests. Survival to hospital discharge is much more likely after arrests with a first documented rhythm of ventricular fibrillation or ventricular tachycardia than after pulseless electric activity and asystole. However, ventricular fibrillation or ventricular tachycardia is not always a favorable rhythm, as survival to discharge is much less likely when ventricular fibrillation or ventricular tachycardia occurs during resuscitation from an arrest with the first documented rhythm of pulseless electric activity or asystole. Further, extracorporeal membrane oxygenation cardiopulmonary resuscitation appears promising under special resuscitation circumstances to improve outcome from highly selected in-hospital pediatric cardiac arrest victims. Further, postresuscitation interventions such as goal-directed therapies and therapeutic hypothermia have been demonstrated in adults and infants to improve outcome for selected cardiac arrest victims and are promising candidate targets for study in children.</AbstractText>Pediatric cardiac arrest is not a futile condition; many children are successfully resuscitated each year. The implementation of new prearrest, intraarrest and postresuscitative therapies has the potential to further improve survival rates following pediatric cardiac arrest.</AbstractText> |
6,638 | Paroxysmal atrial fibrillation after smokeless tobacco (Maras powder) use. | Use of cigarettes and smokeless tobacco is a considerable public health problem. In Turkey, a type of smokeless tobacco called Maras powder (MP) is widely used in the Southeastern region. We present a case of paroxysmal atrial fibrillation that was suspected to be caused by the use of MP, which has never previously been noted in the literature. A 46-year-old man was admitted to our emergency department with angina pectoris and palpitation. He was a long time cigarette smoker and had begun using MP the fortnight before. Electrocardiography showed atrial fibrillation with rapid ventricular response. The patient had no medical history of alcohol use, surgery, palpitation, coronary arterial illness, hypertension or chronic bronchitis. Atrial fibrillation was converted to sinus rhythm after antiarrhythmic medication. Our patient was discharged from the emergency department with a suggestion to quit MP usage immediately. In conclusion, the use of MP may lead to the occurrence of paroxysmal atrial fibrillation. |
6,639 | Transmural optical measurements of Vm dynamics during long-duration ventricular fibrillation in canine hearts. | Knowledge of transmural V(m) changes is important for understanding the mechanism of long-duration ventricular fibrillation (LDVF).</AbstractText>The purpose of this study was to measure transmural V(m) changes during LDVF.</AbstractText>V(m) was recorded optically at up to 8 transmural points separated by 1.5 mm in the left ventricle of Langendorff-perfused canine hearts (n = 6) using a bundle of optical fibers (optrode) during 10 minutes of LDVF followed by 3 minutes of VF with reperfusion. Measurements were grouped into 4 layers: epicardium, subepicardium, midwall, and subendocardium.</AbstractText>Activation rates (ARs) and action potential durations (APDs) decreased, whereas diastolic intervals (DIs) increased during LDVF in all transmural layers (P < .05). After approximately 3 minutes of LDVF, ARs were faster and DIs shorter in the midwall and subendocardium than in the epicardium and subepicardium (P < .05). Activations persisted at the subendocardium but disappeared from other layers after approximately 8 minutes of VF in the majority of hearts. There were no transmural differences in APD during LDVF or during pacing before and after LDVF (P > .05). Restitution plots showed no functional relationship between APD and DI in any layer at any stage of LDVF. Partial reperfusion during VF for 3 minutes restored transmural synchronicity of activation and eliminated gradients in activation parameters.</AbstractText>V(m) dynamics evolve differently at different transmural layers. The subendocardium maintains persistent and the fastest activation during 10 minutes of LDVF, suggesting it contains the source of VF wavefronts. There are no transmural APD gradients and no restitution relationship between APD and DI at any transmural layer, indicating these are not the primary factors in the mechanism of LDVF.</AbstractText> |
6,640 | Mechanisms of recurrent ventricular fibrillation in a rabbit model of pacing-induced heart failure. | Successful defibrillation may be followed by recurrent spontaneous ventricular fibrillation (VF). The mechanisms of postshock spontaneous VF are unclear.</AbstractText>The purpose of this study was to determine the mechanisms of spontaneous VF after initial successful defibrillation in a rabbit model of heart failure (HF).</AbstractText>Simultaneous optical mapping of intracellular calcium (Ca(i)) and membrane potential (Vm) was performed in 12 rabbit hearts with chronic pacing-induced heart failure, in 4 sham-operated hearts, and in 5 normal hearts during fibrillation-defibrillation episodes.</AbstractText>Twenty-eight spontaneous VF episodes were recorded after initial successful defibrillation in 4 failing hearts (SVF group) but not in the remaining 8 failing hearts (no-SVF group) or in the normal or sham-operated hearts. The action potential duration (APD(80)) before pacing-induced VF was 209 +/- 9 ms in the SVF group and 212 +/- 14 ms in the no-SVF group (P = NS). After successful defibrillation, APD(80) shortened to 147 +/- 26 ms in the SVF group and to 176 +/- 14 ms in the no-SVF group (P = .04). However, the duration of Ca(i) after defibrillation was not different between the two groups (246 +/- 21 ms vs 241 +/- 17 ms, P = NS), resulting in elevated Ca(i) during late phase 3 or phase 4 of the action potential. Standard glass microelectrode recording in an additional 5 failing hearts confirmed postshock APD shortening and afterdepolarizations. APD(80) of normal and sham-operated hearts was not shortened after defibrillation.</AbstractText>HF promotes acute shortening of APD immediately after termination of VF in failing hearts. Persistent Ca(i) elevation during late phase 3 and phase 4 of the shortened action potential result in afterdepolarizations, triggered activity, and spontaneous VF.</AbstractText> |
6,641 | Left cardiac sympathetic denervation for the treatment of long QT syndrome and catecholaminergic polymorphic ventricular tachycardia using video-assisted thoracic surgery. | Long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are two of the most common, potentially lethal, cardiac channelopathies. Treatment strategies for the primary and secondary prevention of life-threatening polymorphic ventricular tachycardia/fibrillation include pharmacotherapy with beta-blockers, implantable cardioverter defibrillators, and left cardiac sympathetic denervation (LCSD).</AbstractText>This study sought to report our institutional experience with LCSD using video-assisted thoracic surgery (VATS).</AbstractText>From November 2005 through November 2008, 20 patients (8 female, average age at surgery 9.1 +/- 9.7 years, range 2 months to 42 years) underwent LCSD via either a traditional approach (N = 2) or VATS (N = 18). A total of 12 patients had genotype-positive LQTS (7 LQT1, 2 LQT2, 1 LQT3, 2 LQT1/LQT2), 2 had JLNS, 4 had genotype-negative LQTS, and 2 had CPVT1. Electronic medical records were reviewed for patient selection, perioperative complications, and short-term outcomes.</AbstractText>LCSD was performed as a secondary prevention strategy in 11 patients (8 LQTS patients, average QTc 549 ms) and as primary prevention in 9 patients (average QTc 480 ms). There were no perioperative complications, including no intraoperative ectopy, no uncontrolled hemorrhage, and no VATS cases requiring conversion to a traditional approach. The average length of available follow-up was 16.6 +/- 9.5 months (range 4 to 40 months). Among the 18 patients who underwent VATS-LCSD, the average time from operation to dismissal was 2.6 days (range 1 day to 15 days), the majority being next-day dismissals. Among those receiving LCSD as secondary prevention, there has been a marked reduction in cardiac events.</AbstractText>We present a series of 20 patients with LQTS and CPVT who underwent LCSD, 18 using VATS. The minimally invasive VATS surgical approach was associated with minimal perioperative complications, including no intraoperative ectopy and excellent immediate and short-term outcomes. Videoscopic denervation surgery, in addition to traditional LCSD, offers a safe and effective treatment option for the personalized medicine required for patients with LQTS/CPVT.</AbstractText> |
6,642 | Angiotensin II receptor blockers in the prevention of atrial fibrillation. | Atrial fibrillation (AF) is the most common sustained arrhythmia. While antiarrhythmic agents and electrical cardioversion are highly effective in restoring sinus rhythm, the results obtained in prevention of recurrences are disappointing. Recently, angiotensin II has been recognized as a key factor in atrial structural and electrical remodeling associated with AF. So there are several potential mechanisms by which inhibition of the renin-angiotensin-aldosterone system may reduce AF. In this review, we report the results of studies evaluating the effect of angiotensin II receptor blockers (ARBs) in various clinical settings (i.e., lone AF, hypertension, high-risk patients, congestive heart failure, secondary prevention). However, many of these studies are small and retrospective and have a limited follow-up; moreover, since AF is related to several causes, chiefly heart diseases, patients with different characteristics have often been enrolled. Thus, it is not surprising that the results obtained are frequently conflicting. With these limitations and considering only the results of larger studies with longer follow-up, ARBs are effective in preventing AF in patients with congestive heart failure or hypertension with left ventricular hypertrophy or coronary artery/cerebrovascular disease. In any case, the use of ARBs is not recommended at present in clinical practice to prevent AF. |
6,643 | Atrial-selective sodium channel block for the treatment of atrial fibrillation. | The pharmacological approach to therapy of atrial fibrillation (AF) is often associated with adverse effects resulting in the development of ventricular arrhythmias. As a consequence, much of the focus in recent years has been on development of atrial-selective agents. Atrial-selective sodium channel blockers have recently been shown to exist and be useful in the management of AF. This review summarizes the available data relative to current therapies, focusing on our understanding of the actions of atrial selective sodium channel blockers in suppressing and preventing the induction of AF and electrophysiological properties that confer atrial-selectivity to these antifibrillatory drugs. |
6,644 | Amiodarone attenuates the proarrhythmic effects of dobutamine in patients with advanced congestive heart failure. | The long-term use of positive inotropic pharmaceuticals in patients suffering from end-stage congestive heart failure (CHF) has been associated with increased mortality, presumed to be due to proarrhythmia. Oral amiodarone combined with intermittent dobutamine infusions (IDI), on the other hand, has been shown to increase survival. This study evaluated the effects of oral amiodarone on the arrhythmias caused by dobutamine in patients with advanced CHF.</AbstractText>Thirty patients with CHF, in New York Heart Association functional class III or IV despite optimal medical therapy, were treated with weekly 8-h infusions of dobutamine 10 Ig/kg/min. All patients were treated for 1 month with oral amiodarone, 400 mg/day, before initiation of IDI. A 24-h ambulatory electrocardiogram was recorded on the day before dobutamine infusion and repeated the next day, starting with the onset of infusion.</AbstractText>The average heart rate on the 24-h ambulatory electrocardiogram was 72 +/- 14 beats/min before vs. 72 +/- 12 beats/min during IDI (p=1.000). Likewise, dobutamine did not increase the frequency of premature ventricular complexes (23 +/- 32 per h before vs. 42 +/- 69 per h during infusion, p=0.131), ventricular couplets (18 +/- 36 per 24 h vs. 17 +/- 28 per 24 h, p=0.859), or the incidence of non-sustained ventricular tachycardia (27% vs. 40%, p=0.383). No patient developed ventricular fibrillation or sustained ventricular tachycardia during or after IDI.</AbstractText>Chronic low-dose oral amiodarone attenuates the proarrhythmic effects of dobutamine, increasing the safety of ambulatory IDI.</AbstractText> |
6,645 | Comparison of outcomes of minimally invasive mitral valve surgery for posterior, anterior and bileaflet prolapse. | We sought to compare the outcomes of minimally invasive mitral valve (MV) surgery for anterior (anterior mitral leaflet, AML), posterior (posterior mitral leaflet, PML) or bileaflet (BL) MV prolapse.</AbstractText>Between August 1999 and December 2007, 1230 patients who presented with isolated AML (n=156, 12.7%), isolated PML (n=672, 54.6%) or BL (n=402, 32.7%) MV prolapse underwent minimally invasive MV surgery. The preoperative mitral regurgitation (MR) grade was 3.3+/-0.8, left ventricular ejection fraction (LVEF) was 62+/-12% and mean age was 58.9+/-13.0 years; 836 patients (68.0%) were male. Mean follow-up time was 2.7+/-2.1 years, and the follow-up was 100% complete.</AbstractText>Overall, the MV repair rate was 94.0% (1156 patients). Seventy-four patients (6.0%) received MV replacement. MV repair for PML prolapse was accomplished in 651 patients (96.9%), for AML in 142 patients (91%) and for BL in 363 patients (90.3%). Repair techniques consisted predominantly of leaflet resection and/or implantation of neochordae, combined with ring annuloplasty. Concomitant procedures were tricuspid valve surgery (n=56), atrial fibrillation ablation (n=286) and closure of an atrial septal defect or patent foramen ovale (PFO) (n=89). The overall duration of cardiopulmonary bypass was 127+/-40 min and aortic cross-clamp time was 78+/-33 min. The mean postoperative hospital stay was 11.6+/-9.7 days for the overall group. Early echocardiographic follow-up revealed excellent valve function in the vast majority of patients, regardless of the repair technique, with a mean MR grade of 0.3+/-0.5. For the overall group, 5-year survival rate was 87.3% (95% CI: 83.9-90.1) and 5-year freedom from cardiac reoperation rate was 95.6% (95% CI: 94.1-96.7). The log-rank test revealed no significant difference between the three groups regarding long-term survival or freedom from reoperation.</AbstractText>Minimally invasive MV repair can be achieved with excellent results. Long-term outcomes and reoperation rates for AML prolapse are not significantly different from PML or BL prolapse.</AbstractText> |
6,646 | The effect of biventricular pacing after coronary artery bypass grafting: a prospective randomized trial of different pacing modes in patients with reduced left ventricular function. | Biventricular pacing acutely improves left ventricular function in patients with heart failure and left ventricular dyssynchrony. Pressure-volume loop analysis has shown acute perioperative hemodynamic benefits of biventricular pacing immediately after weaning from cardiopulmonary bypass in patients undergoing coronary artery bypass grafting, but whether these effects can be maintained for the early postoperative period is unclear. We hypothesized that biventricular pacing is superior to atrioventricular universal pacing at right ventricular outflowtract and atrial inhibited pacing in patients undergoing coronary artery bypass grafting.</AbstractText>Ninety-four patients (mean age, 67 +/- 9 years; mean ejection fraction, 35% +/- 4%) were prospectively randomized to undergo biventricular, atrioventricular universal, or atrial inhibited pacing at 90 beats/min for 96 postoperative hours. Clinical end points and postoperative hemodynamics, aminoterminal pro-brain natriuretic peptide, inotropic support, atrial fibrillation, ventricular arrhythmias, and renal function were evaluated.</AbstractText>Diastolic pulmonary arterial pressure, mean arterial pressure, mixed venous saturation, cardiac index, and cardiac power index did not differ significantly among groups for all time points. Neither raw aminoterminal pro-brain natriuretic peptide nor differential from preoperative values differed significantly among groups at any time point. Median intensive care unit stay (19.5 hours) did not differ significantly by pacing mode. Incidences of postoperative atrial fibrillation were 40% for atrial inhibited, 29% for atrioventricular universal, and 37% for biventricular (differences not significant). Renal function was unaffected by pacing mode.</AbstractText>Despite short-term hemodynamic benefits for patients with reduced left ventricular function, biventricular pacing did not lead to improved postoperative hemodynamics or clinical outcome.</AbstractText> |
6,647 | Subclinical hypothyroidism might increase the risk of transient atrial fibrillation after coronary artery bypass grafting. | Some studies have proposed that subclinical hypothyroidism (SCH) has adverse effects on the cardiovascular system, but little is known about the effect on patients undergoing cardiovascular operations. We examined the influence of preoperative SCH on postoperative outcome in patients undergoing coronary artery bypass grafting (CABG).</AbstractText>Among patients who underwent CABG between July 2005 and June 2007 at Seoul National University Bundang Hospital, 224 with normal thyroid function and 36 with SCH were enrolled. Preoperative risks and postoperative outcomes were evaluated prospectively without thyroid hormone replacement.</AbstractText>There were no significant differences in primary outcomes (major adverse cardiovascular events) and secondary outcomes such as wound problems, mediastinitis, leg infection, respiratory complications, delirium, or reoperation during the same hospitalization. However, patients with SCH had a higher incidence of postoperative atrial fibrillation than those with normal thyroid function after adjustment for age, gender, body mass index, and other independent variables such as emergency operation, the use of cardiopulmonary bypass, combined valvular operation, preoperative creatinine levels, left ventricular systolic dysfunction, and nonuse of beta-blockers (45.5% vs 29%; odds ratio, 2.552; 95% confidence interval, 1.117 to 5.830; p = 0.026).</AbstractText>SCH appears to influence the postoperative outcome for patients by increasing the development of postoperative atrial fibrillation. However, it is still unproven whether preoperative thyroxine replacement therapy for patients with SCH might prevent postoperative atrial fibrillation after CABG.</AbstractText> |
6,648 | The Toronto Root bioprosthesis: midterm results in 186 patients. | The Toronto Root bioprosthesis with BiLinx anticalcification treatment (St. Jude Medical, St. Paul, MN) was introduced into clinical practice in 2001, mainly for patients with aortic valve disease and additional pathology of the aorta. Patients included in the initial clinical study with core laboratory data evaluation were reviewed.</AbstractText>A total of 186 patients (62 +/- 11 years, 38 female) received full root replacement at our institution with the Toronto Root bioprosthesis from June 2001 until November 2007. The predominant aortic valve lesion was stenosis in 34, incompetence in 80, and mixed lesions in 72 patients. Additional procedures included replacement of the ascending aorta in 139, replacement of the ascending aorta plus aortic arch in 38, coronary artery bypass graft surgery in 31, mitral valve repair in 26, atrial fibrillation ablation in 14, and atrial septal defect closure in 8 patients. Previous cardiac surgery had been performed in 10 patients. Mean follow-up was 50 +/- 26 months (770 patient-years).</AbstractText>The mean implanted valve size was 26.8 +/- 1.8 mm (14 x 23 mm, 36 x 25 mm, 87 x 27 mm, and 48 x 29 mm). Aortic cross-clamp time was 99.8 +/- 29 minutes, and cardiopulmonary bypass time was 140.9 +/- 52 minutes. All patients showed a clinical improvement of at least one New York Heart Association class during follow-up. Most recent echocardiographic examination revealed a maximum transvalvular blood flow velocity of 2.1 +/- 0.5 m/s and a mean pressure gradient of 9.6 +/- 8.5 mm Hg. Left ventricular ejection fraction was 61% +/- 11%. Early mortality was 5.9% +/- 1.7%, and 5-year survival was 83.3% +/- 3.0%. Patients who underwent isolated aortic root surgery had a 5-year survival of 90.3% +/- 4.2%.</AbstractText>The Toronto Root bioprosthesis is safe and provides good clinical and hemodynamic function after full root replacement with or without additional aortic surgery. Owing to the specific anticalcification treatment, long-term durability may be promising.</AbstractText> |
6,649 | Relation of immediate decrease in ventricular septal strain after alcohol septal ablation for obstructive hypertrophic cardiomyopathy to long-term reduction in left ventricular outflow tract pressure gradient. | Alcohol septal ablation (ASA) aims to decrease left ventricular outflow tract (LVOT) obstruction in patients with obstructive hypertrophic cardiomyopathy (HC). To date, no diagnostic variables at baseline are available to predict long-term success of the procedure. We hypothesized that an immediate decrease in septal longitudinal strain after ASA would be associated with sustained LVOT gradient decrease after 6 months. ASA was performed in 22 patients with HC and severe drug-refractory symptoms. Clinical evaluation and 2-dimensional echocardiography were performed before, 1 day after, and 6 months after ASA. During 6-month follow-up, New York Heart Association class improved (2.7 +/- 0.5 vs 1.4 +/- 0.6, p <0.01) and LVOT gradient decreased (68 +/- 31 vs 21 +/- 21 mm Hg, p <0.01). Strain evaluation showed considerable decreases in basal septal strain (-12 +/- 3% vs -8 +/- 2%, p <0.01) and midseptal strain (-13 +/- 4% vs -8 +/- 3%, p <0.01) 1 day after ASA. Decreases in basal septal and midseptal strain 1 day after ASA were strongly related to the decrease in LVOT gradient during 6-month follow-up (r = 0.70, p <0.01, and r = 0.65, p <0.01, respectively). In conclusion, in patients with HC and severe drug-refractory symptoms, immediate decrease in septal strain after ASA is strongly related to a decrease in LVOT gradient after 6 months and might therefore serve as an early determinant for long-term success of the ASA procedure. |
6,650 | [Morphological prerequisites of heart ventricles fibrillation in sudden cardiac death]. | We studied morphological changes in the myocardium and content of glucose, magnesium, calcium, sodium in pericardial fluid of victims of out of hospital sudden death due to acute coronary insufficiency and prenecrotic stage of myocardial infarction. We established that both in regions of ischemic injury appearing as III degree contracture lesions of cardiomyocytes, zones of intracellular myocytolysis and primary breakdown of myofibrils, as will as in zones of relaxation myocardium loses its contractile properties. This in turn leads to asynchronous contraction of left and right ventricles. As fibrillation develops in both ventricles simultaneously there are all grounds to believe that morphological prerequisite (source of origin) of fibrillation is the presence of areas of ischemic injury and relaxation in the myocardium. |
6,651 | Impact of atrial antitachycardia pacing and atrial pace prevention therapies on atrial fibrillation burden over long-term follow-up. | Selective atrial pacing algorithms have been developed for prevention of atrial tachycardia/atrial fibrillation (AT/AF). Although short-term studies have shown modest to minimal incremental benefit of these algorithms compared with conventional dual-chamber (DDD/R) pacing for prevention of AT/AF, the long-term effects of these algorithms are unknown. Accordingly, we compared atrial antitachycardia pacing (ATP) therapy and combined atrial ATP and atrial pace prevention (ATP + Prevention) algorithms to conventional DDD/R pacing for prevention of AT/AF over long-term follow-up.</AbstractText>Seventy-one patients with AT/AF following pacemaker insertion were randomized to DDD/R pacing, DDD/R plus ATP pacing, or DDD/R plus ATP and prevention pacing and followed for 3 years. Atrial tachycardia/AF burden and an AF symptom scale were compared over time between groups. Atrial tachycardia/AF burden remained stable over 3 years in the DDD/R and ATP + Prevention groups. Atrial tachycardia/AF burden increased significantly over time in the ATP group. Patients not on class I or III antiarrhythmic drug therapy were more likely to experience an increase in AT/AF burden over time.</AbstractText>Atrial ATP and atrial ATP in combination with atrial pace prevention algorithms do not suppress AT/AF over long-term follow-up compared with DDD/R pacing.</AbstractText> |
6,652 | Selecting the transthoracic defibrillation shock directional vector based on VF amplitude improves shock success. | Termination of ventricular fibrillation (VF) by a defibrillating shock is more likely to occur when the VF amplitude is larger. We hypothesized that a defibrillation shock would achieve higher success if the shock vector was oriented along the largest of the VF amplitudes measured simultaneously in 3 orthogonal ECG leads, and that this axis could be determined near-instantaneously in real time.</AbstractText>In 9 closed-chest anesthetized swine, a new directional defibrillation (DD) device was used to simultaneously measure the VF peak amplitudes displayed by 3 orthogonal pairs of defibrillation electrodes: anterior-posterior, lateral-lateral, and superior-inferior. Four shocks at each of 3 energy levels (30 Joules [J], 50 J, and 100 J) were delivered through the electrode pair measuring the largest (LA) and smallest (SA) VF peak amplitude at the time of the shock. The odds of shock success (VF termination followed by a perfusing rhythm) were 5 times more likely when shocks were delivered from the LA electrodes than the SA electrodes (odds ratio 5.10, 95% CI: 1.39, 18.79). At the intermediate energy level of 50 J, shocks delivered through the LA electrode pairs had an almost 9 times higher odds of shock success than 50 J shocks delivered through the SA electrode pairs (68.3% vs 18.9%, P = 0.002) (odds ratio 8.94, 95% CI: 2.59, 30.82). Transthoracic impedance and current did not differ for shocks delivered in the LA versus SA groups.</AbstractText>Choosing the defibrillation directional vector based on the largest VF amplitude improved shock success.</AbstractText> |
6,653 | Atrial fibrillation and the risk of death in patients with heart failure: a literature-based meta-analysis. | Heart failure (HF) and atrial fibrillation (AF) are common, associated with significant morbidity and mortality, and frequently coexist. It is uncertain from published data if the presence of AF in patients with HF is associated with an incremental adverse outcome. The aim of this study was to combine the results of all studies investigating prognosis for patients with HF and AF compared with those in sinus rhythm (SR) to asses the mortality risk associated with this arrhythmia.</AbstractText>Electronic databases were searched (Biological Abstracts, Current Contents, EMBASE, Medline, Medline In-progress, PubMed and Scopus), to 31 December 2006, using the key words congestive heart failure, heart failure, ventricular dysfunction, atrial fibrillation, atrial flutter, sinus rhythm, prognosis, outcome, death and hospitalization. Bibliographies of retrieved publications were hand searched. Studies were eligible if they included a HF population and if outcomes were reported by cardiac rhythm (AF or SR). Studies were reviewed by predetermined protocol (including quality assessment). Data were pooled using a random effects model.</AbstractText>Twenty studies were included (from 3380 initially identified) representing 32946 patients (10819 deaths). Nine randomized controlled trials (RCT) were included. The prevalence of AF was 15%, crude mortality rates were 46% (AF) and 33% (SR). The odds ratio for death was 1.33 (95% confidence interval (CI) 1.12-1.59) for AF compared with SR. Eleven observational studies were included. The prevalence of AF was 23%, crude mortality rates were 38% (AF) and 25% (SR). The odds ratio for death was 1.57 (95% CI 1.20-2.05) for AF compared with SR.</AbstractText>This meta-analysis demonstrates that AF is associated with worse outcomes for patients with HF compared with those with SR. Further research is required to determine whether the adverse outcome associated with AF is related to the arrhythmia itself, or to variables, such as HF severity, patient age and comorbidity.</AbstractText> |
6,654 | Factors affecting immediate changes in cardiac output following balloon mitral valvulotomy: the role of pulmonary hemodynamics. | The study aim was to investigate the factors that affect changes in cardiac output (CO) following balloon mitral valvulotomy (BMV), which at present are essentially unknown.</AbstractText>Among a total of 168 patients, clinical, echocardiographic and hemodynamic data before and after BMV were compared between patients in group I (<15% increase in CO after BMV) and group II (>15% increase). A multiple logistic regression analysis was used to identify factors that were predictive of an increase in CO.</AbstractText>Before BMV, the mean CO was 3.9 +/- 0.9 and 4.1 +/- 0.71/min (p = NS) in groups I and II, respectively. Group I patients were more symptomatic, with a greater proportion in NYHA class > or =3. The pulmonary artery mean pressure (PAMP) was also higher in group I patients (51 +/- 20 mmHg) than in group II (35 +/- 12 mmHg) (p < 0.03). Pulmonary vascular resistance (PVR) was also higher in group I than in group II (6.9 +/- 3.6 and 4.0 +/- 3.0 Woods units, respectively; p < 0.02). Right ventricular function, left ventricular ejection fraction (LVEF), heart rate, mitral valve area, transmitral mean gradient, Wilkin's valve score and incidence of atrial fibrillation were similar in both groups. After BMV, the CO was 4.1 +/- 0.8 and 4.8 +/- 0.8 1/min (p < 0.005) in groups I and II, respectively. Likewise, there was similar inter-group increase in valve area and a decrease in mean gradient. The PAMP was reduced in both groups compared to pre-BMV, but remained higher in group I than in group II (35 +/- 17 and 21 +/- 9 mmHg, respectively; p < 0.05). PVR was decreased in group II and remained higher in group I (2.8 +/- 1.8 and 6.1 +/- 2.6 Woods units, respectively; p < 0.05). The magnitude of iatrogenic interatrial shunt was similar in both groups. Following BMV, a >50% fall in PVR was predictive of an increase in CO by 15% (OR 5.7, 95% CI 3.1-7.8).</AbstractText>Patients with a post-BMV increase in CO had a lower pre-procedure PAMP and PVR. In group I, a high PVR ('second stenosis') did not fall after BMV. In spite of an apparent overall improvement in hemodynamics, there was a suboptimal rise in CO. PAMP, despite a significant fall, remained higher than normal. The pulmonary hemodynamics were seen to influence changes in CO after BMV, despite similar changes in valve area and mean gradients, with similar Wilkin's scores and right ventricular function between the two groups. A fall of >50% in PVR is predictive of a post-BMV increase in CO.</AbstractText> |
6,655 | Cardiac amyloidosis treated with an implantable cardioverter defibrillator and subcutaneous array lead system: report of a case and literature review. | Preventing ventricular arrhythmias in patients with cardiac amyloidosis is challenging since the amyloid protein deposition in the myocardium may interfere with the normal cardiac electric excitation. Most of these patients succumb to either progressive congestive heart failure, or sudden cardiac death (SCD). Implantable cardioverter defibrillator (ICD) offers a near sure means of preventing SCD.</AbstractText>Myocardial infiltration with amyloid results in elevated defibrillation threshold (DFT). Intra-operative strategies may fail to lower DFT during implantation.</AbstractText>We present a case of a 64-year-old female who had cardiac amyloidosis, and was successfully treated with an ICD and a subcutaneous array lead system.</AbstractText>A subcutaneous array lead system is useful in reducing the DFT, and can terminate ventricular tachycardia or fibrillation by allowing more energy delivery and efficient defibrillation.</AbstractText> |
6,656 | Ischemia and reperfusion-induced arrhythmias: role of hyperoxic preconditioning. | Hyperoxic preconditioning is known to protect the heart against necrosis and contractile dysfunction, but protection against arrhythmias has not been well characterized.</AbstractText>The authors hypothesized that pre-exposure to normobaric hyperoxia (H) reduces ischemia and reperfusion-induced arrhythmias in isolated rat hearts.</AbstractText>Following 60 and 180 min of hyperoxia treatment, rat hearts were isolated immediately (H60 and H180) or 24 h afterward (H60/24 and H180/24), and subjected to 30 min of regional ischemia followed by 120 min of reperfusion. Occurrence, number, and duration of arrhythmias were analyzed during ischemia and reperfusion. In addition, cardiac infarct size was also assessed.</AbstractText>Sixty and 180 min of breathing hyperoxic gas induced significant protection against severe ischemia and reperfusion-induced arrhythmias. Total number of premature ventricular beats was markedly attenuated by hyperoxia pre-exposure, especially in H60 and H180 groups. Duration of ventricular tachycardia and ventricular fibrillation was also affected by hyperoxia. Hyperoxia reduced the number of ventricular tachycardia episodes in ischemia and reperfusion phase. Accordingly, severity of arrhythmias (arrhythmia score) and infarct size were lower in hyperoxia-treated groups. The effects were more pronounced using hyperoxia immediately before harvesting the heart.</AbstractText>These results indicate that hyperoxic preconditioning attenuates ventricular ischemia and reperfusion-induced arrhythmias in isolated rat hearts, decreases cardiac infarct size, and improves postischemic heart function. The effects seem to depend on the time course after hyperoxia treatment.</AbstractText> |
6,657 | Initial defibrillation versus initial chest compression in a 4-minute ventricular fibrillation canine model of cardiac arrest. | Previous laboratory and clinical studies have demonstrated that chest compression preceding defibrillation in prolonged ventricular fibrillation (VF) increases the likelihood of successful cardiac resuscitation. The lower limit of VF duration when preshock chest compression provides no benefit has not been specifically studied. We aimed to study the effect of order of defibrillation and chest compression on defibrillation and cardiac resuscitation in a 4-minute VF canine model of cardiac arrest.</AbstractText>Prospective, randomized animal study.</AbstractText>Key Laboratory of Cardiovascular Remodeling and Function Research and Department of Cardiology, QiLu Hospital.</AbstractText>Twenty-four domestic dogs.</AbstractText>VF was induced in anesthetized and ventilated canines. After 4 minutes of untreated VF, animals were randomly assigned to receive shock first or chest compression first. Animals in the shock-first group received an immediate single countershock of 360 J for <10 seconds, then 200 immediate compressions before pulse check or rhythm reanalysis. The ratio of compression to ventilation was 30:2. Interruptions to deliver rescue breaths were eliminated in this study. Animals in the chest compression-first group received 200 chest compressions before a single countershock; the other interventions were the same as for the shock-first group. End points were restoration of spontaneous circulation (ROSC), defined as spontaneous systolic arterial pressure >50 mm Hg, when epinephrine (0.02 mg/kg intravenously) was given, and resuscitation, defined as maintaining systolic arterial pressure >50 mm Hg at the 24-hour study end point.</AbstractText>In the shock-first group, all animals achieved ROSC, and ten of 12 survived at the 24-hour study end point. In the chest compression-first group, 11 of 12 animals achieved ROSC, and nine of 12 survived at the 24-hour study end point.</AbstractText>In this 4-minute VF canine model of cardiac arrest, the order of initial defibrillation or initial chest compression does not affect cardiac resuscitation.</AbstractText> |
6,658 | Contemporary analysis of predictors and etiology of ventricular fibrillation during diagnostic coronary angiography. | To assess the incidence, investigate the predictors and analyze the causes of ventricular fibrillation (VF) during coronary angiography (CA) on the condition of current techniques.</AbstractText>From April 2004 to January 2007, a total 22,254 patients (27,798 procedures) received CA procedures in our center; 27 patients developed VF during CA. This report was to retrospectively analyze the clinical basic characteristics, coronary angiographic characteristics and CA procedure records of these patients.</AbstractText>The incidence of VF during CA was 0.097%. The incidence of VF in radial approaches and femoral approaches was 0.076% and 0.147% (p = 0.085). The VF patients had higher coronary artery bypass grafting (CABG) rates (11.1% vs 2.3%, p = 0.024) and were more likely to have a three-vessel disease (59.3% vs 31.2%, p = 0.002) and a total occlusion lesion (25.9% vs 11.1%, p = 0.014) than non-VF patients. On logistic regression analysis, three-vessel disease (OR: 2.582, 95% CI: 1.165-5.720, p = 0.019) and the history of CABG (OR: 3.959, 95% CI: 1.160-13.513, p = 0.028) were the two independent predictors of VF occurrences. Among 27 episodes of VF, 13 were ischemia-related; 11 were manipulation-related; two were contrast-related; one was hypokalemia-related; and the causes remain unclear in five episodes.</AbstractText>The incidence of VF during CA is low on the condition of current techniques. The severity of coronary artery disease (CAD) is an independent predictor of VF occurrence during CA. Acute ischemia and inappropriate manipulation may be the two main causes in VF development.</AbstractText>(c) 2009 Wiley Periodicals, Inc.</CopyrightInformation> |
6,659 | C-type natriuretic peptide production by the human kidney is blunted in chronic heart failure. | CNP (C-type natriuretic peptide) is a vasodilatory peptide produced by vascular endothelium and the human heart with a short half-life. CNP has been identified within the human kidney; however, few results are available on whether the human kidney is a systemic source of CNP. The aim of the present study was to establish whether CNP is secreted by the human kidney and if synthesis is blunted in CHF (chronic heart failure). A total of 20 male subjects (age, 57+/-2 years; mean+/-S.E.M.) undergoing CHF assessment (n=13) or investigation of paroxysmal supraventricular arrhythmia (normal left ventricular function in sinus rhythm during procedure) (n=7) were recruited. Renal CNP production was determined from concomitant plasma concentrations in the aorta and renal vein. When considering all subjects, a significant step-up in plasma CNP was found from the aorta to renal vein (3.0+/-0.3 compared with 8.3+/-2.4 pg/ml respectively; P=0.0045). The mean increase in CNP was 5.3+/-2.4 pg/ml (range, -0.9 to +45.3 pg/ml). In patients with CHF, the aortic concentration was 3.3+/-0.4 pg/ml compared with a renal vein concentration of 4.3+/-0.6 pg/ml (P=0.11). In those with normal left ventricular function, the respective values were 2.5+/-0.5 and 15.7+/-6.0 pg/ml (P=0.01). In conclusion, CNP is synthesized and secreted into the circulation by the normal human kidney, where it may have paracrine actions. Net renal secretion of CNP appears to be blunted in patients with CHF. |
6,660 | Idiopathic ventricular fibrillation associated with J wave and early repolarization: a really benign electrocardiographic sign? | Evaluation of: Sudden cardiac arrest associated with early repolarization. Haiissaguerre M, Derval N, Saccher F et al.: N. Engl. J. Med. 358, 2016-2023 (2008). In patients with idiopathic ventricular fibrillation, several kinds of electrocardiographic findings have been reported. Brugada electrocardiogram (ECG), a coved-type ST-segment elevation in the right precordial leads, is a well-known electrocardiographic sign, which is related to ventricular fibrillation leading to sudden cardiac death. By contrast, J wave and early repolarization are generally considered as benign manifestations on the ECG; however, they are reported as having the potential to cause cardiac arrhythmias at experimental studies. This study revealed that J wave and early repolarization were more frequent in patients with idiopathic ventricular fibrillation compared with control subjects (31 vs 5%; p < 0.0001). Moreover, a higher incidence of recurrent ventricular fibrillation was observed in patients with J wave and early repolarization on the ECG compared with those without such abnormalities (HR: 2.1; 95% CI: 1.2-3.5; p = 0.008). This study raises a question on the general concept that J wave and early repolarization are benign electrocardiographic patterns. |
6,661 | Genetic and clinical profile of Indian patients of idiopathic restrictive cardiomyopathy with and without hypertrophy. | Both idiopathic restrictive cardiomyopathy (IRCM) and hypertrophic cardiomyopathy (HCM) are part of the same disease spectrum and are due to sarcomeric gene mutations. A patient with restrictive physiology without left ventricular hypertrophy (LVH) would be diagnosed as IRCM, while one with LVH would be diagnosed as HCM with restrictive physiology. We studied a group of patients with restrictive physiology for mutations in beta-myosin heavy chain (MYH7) and troponin I (TNNI3) gene. Consecutive probands in the HCM and IRCM cohort over a 4-year period were considered for this study. These included 10 IRCM and 102 HCM patients. All were Asian Indians. Among the 17 patients who had restrictive physiology 10 were IRCM patients and seven were HCM patients. Of the HCM patients, seven (6.9%) had restrictive physiology. Mean age of these 17 patients was 40.1 +/- 19.2 years (range: 15-67 ), six (35.3%) were males. Maximal left ventricular wall thickness of the seven HCM probands was 20.7 +/- 5.2 mm (range: 16-31), while it was normal in the IRCM probands. Ten probands (58.8%) were in NYHA class III or IV. Seven patients (41.2%) had atrial fibrillation. All the probands were screened for mutations in selected exons of MYH7 and TNNI3 genes. One IRCM patient was found to have p.Arg721Lys mutation in the MYH7 gene. She died due to progressive congestive cardiac failure at the age of 47 years. One HCM proband with a maximal left ventricular wall thickness of 17 mm had p.Arg192His mutation in the TNNI3 gene. She had features consistent with restrictive physiology. Her father and sister had died of restrictive cardiomyopathy. IRCM and HCM with restrictive physiology, both are part of the clinical expression of MYH7 and TNNI3 mutations and lead to worse clinical onset and progression of the disease. |
6,662 | Prediction of countershock success: a comparison of autoregressive and fast fourier transformed spectral estimators. | Spectral analysis of the ventricular fibrillation (VF) ECG has been used for predicting countershock success, where the Fast Fourier Transformation (FFT) is the standard spectral estimator. Autoregressive (AR) spectral estimation should compute the spectrum with less computation time. This study compares the predictive power and computational performance of features obtained by the FFT and AR methods.</AbstractText>In an animal model of VF cardiac arrest, 41 shocks were delivered in 25 swine. For feature parameter analysis, 2.5 s signal intervals directly before the shock and directly before the hands-off interval were used, respectively. Invasive recordings of the arterial pressure were used for assessing the outcome of each shock. For a proof of concept, a micro-controller program was implemented.</AbstractText>Calculating the area under the receiver operating characteristic (ROC) curve (AUC), the results of the AR-based features called spectral pole power (SPP) and spectral pole power with dominant frequency (DF) weighing (SPPDF) yield better outcome prediction results (85%; 89%) than common parameters based on FFT calculation method (centroid frequency (CF), amplitude spectrum area (AMSA)) (72%; 78%) during hands-off interval. Moreover, the predictive power of the feature parameters during ongoing CPR was not invalidated by closed-chest compressions. The calculation time of the AR-based parameters was nearly 2.5 times faster than the FFT-based features.</AbstractText>Summing up, AR spectral estimators are an attractive option compared to FFT due to the reduced computational speed and the better outcome prediction. This might be of benefit when implementing AR prediction features on the microprocessor of a semi-automatic defibrillator.</AbstractText> |
6,663 | Are our medical graduates in New Zealand safe and accurate in ECG interpretation? | We aimed to assess the skills of final year medical students and resident medical officers in recognising and interpreting important common or life-threatening abnormalities in the electrocardiogram (ECG).</AbstractText>102 participants at two study sites (52 of whom were final year medical students) attempted to determine the heart rate and rhythm and identify and interpret any abnormalities present in 15 ECGs in a 30-minute time period.</AbstractText>Accurate determination of heart rate was poor, ranging from 0% to 89% correct across the 15 ECGs. Normal sinus rhythm in 8 ECGs was identified 81% to 95% of the time, and ventricular tachycardia was identified by 98% of participants. Atrial fibrillation (55%), second degree heart block (19%) and ventricular pacing (9%) were not well identified. Four ECGs showed acute ischaemic ST segment changes, and these were correctly identified in 87% to 93% of cases, although interpretation of these abnormalities was less accurate. Long QT interval (7%) and pre-excitation (WPW pattern, 11%) were not well recognised. Nearly half of the participants rated their ability to interpret ECGs as less than satisfactory while just over half rated the ECG teaching they had received as less than satisfactory.</AbstractText>Overall study participants did not achieve what we would consider an adequate standard in recognising and interpreting important common or life-threatening abnormalities in the ECG. To address this we need to define minimum standards in ECG interpretation, to improve our teaching to meet these standards, and to assess our graduates against these.</AbstractText> |
6,664 | Electrical cardioversion. | External electrical cardioversion was first performed in the 1950s. Urgent or elective cardioversions have specific advantages, such as termination of atrial and ventricular tachycardia and recovery of sinus rhythm. Electrical cardioversion is life-saving when applied in urgent circumstances. The succcess rate is increased by accurate tachycardia diagnosis, careful patient selection, adequate electrode (paddles) application, determination of the optimal energy and anesthesia levels, prevention of embolic events and arrythmia recurrence and airway conservation while minimizing possible complications. Potential complications include ventricular fibrillation due to general anesthesia or lack of synchronization between the direct current (DC) shock and the QRS complex, thromboembolus due to insufficient anticoagulant therapy, non-sustained VT, atrial arrhythmia, heart block, bradycardia, transient left bundle branch block, myocardial necrosis, myocardial dysfunction, transient hypotension, pulmonary edema and skin burn. Electrical cardioversion performed in patients with a pacemaker or an incompatible cardioverter defibrillator may lead to dysfunction, namely acute or chronic changes in the pacing or sensitivity threshold. Although this procedure appears fairly simple, serious consequences might occur if inappropriately perfformed. |
6,665 | Right ventricular pacing is associated with impaired overall survival, but not with an increased incidence of ventricular tachyarrhythmias in routine cardioverter/defibrillator recipients with reservedly programmed pacing. | Data from previous defibrillator studies raised concern about right ventricular pacing (RVP) promoting heart failure progression and mortality in implantable cardioverter/defibrillator (ICD) patients. The present observational study re-examined the association of RVP, survival, and ventricular tachyarrhythmias/ventricular fibrillation (VT/VF) in routine ICD patients with restrictively programmed pacing.</AbstractText>In 213 ICD patients [183 men, left ventricular ejection fraction (LVEF) 37 +/- 15%, follow-up 37 +/- 18 months, no advanced atrioventricular (AV) block], the RVP proportion, survival, and the time to a first appropriate VT/VF episode were assessed. Electrograms were validated and the overall survival was determined. The RVP prevalence was dichotomized at > or = 30% (high RVP) vs. <30% (low RVP). High RVP (RVP 94%, n = 24) and low RVP (RVP 0%, n = 189) patients had similar LVEF, underlying heart disease, ICD indication, and medication. Multivariate Cox regression showed no difference in survival without appropriate VT/VF treatment [odds ratio (OR): 0.92, 95% confidence interval (CI): 0.41-2.04, P = 0.83]. Overall survival was significantly more favourable in low RVP patients (OR: 0.34, CI: 0.13-0.91, P = 0.03).</AbstractText>Frequent RVP is associated with impaired survival in ICD patients despite conservative pacing settings. Implantable cardioverter/defibrillator patients requiring concomitant bradycardia pacing should be cared for with particular attention to clinical worsening. Right ventricular pacing prevention and alternative modalities of ventricular pacing need prospective evaluation.</AbstractText> |
6,666 | The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) trial: clinical rationale, study design, and implementation. | No large randomized multicentre trial has evaluated the efficacy of radiofrequency ablation (RFA) vs. anti-arrhythmic drug (AAD) therapy as a first-line treatment of paroxysmal atrial fibrillation (AF).</AbstractText>The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation (MANTRA-PAF) trial is a randomized, controlled, parallel group, multicentre study designed to test whether catheter-based RFA is superior to optimized AAD therapy in suppressing relapse within 24 months of symptomatic and/or asymptomatic AF in patients with paroxysmal AF without prior AAD therapy. The primary endpoint is cumulative AF burden on repeated 7 days Holter monitoring. Secondary endpoints are: thromboembolic events, hospitalization due to arrhythmia, pro-arrhythmic events, procedure/treatment-related side effects, health economics, quality of life, and change in left ventricular function. Ten centres in Scandinavia and Germany are participating in the study. Enrolment was started in 2005 and as of November 2008, 260 patients have been enrolled into the study. It is expected that enrolment will end by March 2009, when 300 patients have been included.</AbstractText>The MANTRA-PAF trial will determine whether catheter-based RFA is superior to optimized AAD therapy as a first-line treatment in suppressing long-term relapse of symptomatic and/or asymptomatic AF.</AbstractText> |
6,667 | A fast-growing obstructive left atrial intramural hematoma causing acute prolonged chest pain. | A 74-year-old woman was at the emergency department for acute chest pain, dyspnea and severe transient hypotension. History was arterial hypertension and external electrical cardioversion (EEC) for persistent atrial fibrillation (AF) 8 days before admission. At that time echocardiography was normal. The patient underwent coronary angiography with no evidence of significant coronary arteries disease. At echocardiography a large multi-loculated mass occupying most of the left atrial space and obstructing left ventricular inflow was evident. There was mild pericardial effusion. The patient was operated and a large thrombus totally encompassed in the left atrial wall was removed. Initial tearing into the pericardial space was revealed. Post-surgical follow-up was uneventful and at 3-6 months normalization of the atrial cavity with blending of atrial endocardium and epicardium was demonstrated. No apparent etiological factor was found. We have provided evidence of the possible rapid formation of a large intramural atrial hematoma. Spontaneous atrial wall dissection should be considered in the differential diagnosis of chest pain. |
6,668 | Recurrence of ventricular tachycardia degeneration by low-energy implantable cardioverter-defibrillator shocks: a case report. | Despite their proven efficacy at reducing mortality in selected patients, implantable cardioverter-defibrillators have some proarrhythmic effects. In this report, we present a case of a patient with recurrent ventricular tachycardia degeneration to ventricular fibrillation by appropriate low-energy implantable cardioverter-defibrillator shocks. |
6,669 | Intracoronary acid infusion as an alternative to ischemic postconditioning in pigs. | Previous studies suggested that prolongation of acidosis during reperfusion is protective and may be an important mechanism of postconditioning protection. The aim of this study was to analyze the therapeutic value of this intervention during in vivo coronary reperfusion, and to compare it with ischemic postconditioning. Pigs were submitted to 48 or 60 min of ischemia and 2 h of reperfusion. Animals were allocated to either intracoronary infusion of Krebs solution at dose and duration previously described as optimal in rat hears (pH 6.4 for the first 3 min of reperfusion), ischemic postconditioning (8 cycles of 30 s ischemia/reperfusion) or their respective control groups (n = 9-11 per group). Neither prolongation of acidosis nor postconditioning modified infarct size after 48 min of ischemia as compared to pooled controls. In contrast, in animals submitted to 60 min of coronary occlusion, infarct size was reduced both by infusion of acid Krebs and ischemic postconditioning (57.92 +/- 18.15% and 56.91 +/- 7.50 vs. 75.37 +/- 9.29% in controls, P < 0.01), despite having similar areas at risk. However, an increased incidence of ventricular fibrillation was observed in pigs reperfused with acid Krebs as compared to ischemic postconditioning (11 out of 20 vs. 3 out of 19 pigs, P < 0.05). In conclusion, in pigs submitted to coronary occlusion, intracoronary acid infusion and postconditioning offered protection against cell death only after prolonged coronary occlusion. Both interventions were equally effective, but intracoronary acid infusion was associated with high risk of ventricular fibrillation. These results are strongly against translation of acidic reperfusion to patients with acute myocardial infarction. |
6,670 | Sympathetic excitation during exercise as a cause of attenuated heart rate recovery in patients with myocardial infarction. | Heart rate recovery (HRR) after exercise is known as a predictor of cardiac death in patients with heart disease. The mechanism is not fully understood, although a parasympathetic mechanism has been reported. To elucidate the factors that influence HRR, we evaluated the relationship of HRR with exercise performance and plasma norepinephrine (NE), lactic acid and B-type natriuretic peptide (BNP) responses to exercise testing.</AbstractText>The study population consisted of 52 male patients (age 58 +/- 9.6 years) who had experienced myocardial infarction without residual ischemia, uncompensated heart failure or atrial fibrillation. All subjects underwent a symptom-limited cardiopulmonary exercise test without a cool-down period and echocardiography. NE, lactic acid and BNP were measured at rest and at peak exercise.</AbstractText>HRR did not correlate with the left ventricular ejection fraction, peak VO(2), lactic acid and BNP. HRR significantly correlated with the increment in heart rate (HR) from rest to peak exercise (DeltaHR) (r=0.30, p<0.05). When we divided DeltaHR into two phases at the anaerobic threshold (AT), HRR significantly correlated with DeltaHR (peak-AT) (r=0.409, p<0.01), but not with DeltaHR (AT-rest). There was a significant negative correlation between HRR and NE both at rest and at peak exercise (r=-0.286, p<0.05, r=-0.310, p<0.05). HRR was also correlated significantly with DeltaHR/logDeltaNE as an index of sensitivity to NE (r=0.421, p<0.01). Based on multiple regression analysis, DeltaHR and logDeltaNE predicted HRR (R(2)=0.467, p=0.0027).</AbstractText>Present findings suggest that enhanced sympathetic excitation at maximum exercise suppresses parasympathetic reactivation and results in attenuation of HRR.</AbstractText> |
6,671 | Pharmacological characteristics and clinical applications of K201. | K201 is a 1,4-benzothiazepine derivative that is a promising new drug with a strong cardioprotective effect. We initially discovered K201 as an effective suppressant of sudden cardiac cell death due to calcium overload. K201 is a non-specific blocker of sodium, potassium and calcium channels, and its cardioprotective effect is more marked than those of nicorandil, prazosine, propranolol, verapamil and diltiazem. Recently, K201 has also been shown to have activities indicated for treatment of atrial fibrillation, ventricular fibrillation, heart failure and ischemic heart disease, including action as a multiple-channel blocker, inhibition of diastolic Ca(2+) release from the sarcoplasmic reticulum, suppression of spontaneous Ca(2+) sparks and Ca(2+) waves, blockage of annexin V and provision of myocardial protection, and improvement of norepinephrine-induced diastolic dysfunction. Here, we describe the pharmacological characteristics and clinical applications of K201. |
6,672 | Novel approaches for pharmacological management of atrial fibrillation. | In the light of the progressively increasing prevalence of atrial fibrillation (AF), medical awareness of the need to develop improved therapeutic approaches for the arrhythmia has also risen over the last decade. AF reduces quality of life and is associated with increased morbidity and mortality. Despite several setbacks as a result of negative results from rhythm control trials, the potential advantages of sinus-rhythm (SR) maintenance have motivated continued efforts to design novel pharmacological options aiming to terminate AF and prevent its recurrence, with a hope that optimized medical therapy will improve outcomes in AF patients. Pathophysiologically, AF is associated with electrical and structural changes in the atria, which increase the propensity to arrhythmia perpetuation but may eventually allow for new modalities for therapeutic intervention. Antiarrhythmic drug therapy has traditionally targeted ionic currents that modulate excitability and/or repolarization of cardiac myocytes. Despite efficacious suppression of ventricular and supraventricular arrhythmias, traditional antiarrhythmic drugs present problematic risks of pro-arrhythmia, potentially leading to excess mortality in the case of Na+-channel blockers or IKr (IKr=the rapid component of the delayed rectifier potassium current) blockers. New anti-AF agents in development do not fit well into the classical Singh and Vaughan-Williams formulation, and are broadly divided into 'atrial-selective compounds' and 'multiple-channel blockers'. The prototypic multiple-channel blocker amiodarone is the most efficient presently available compound for SR maintenance, but the drug has extra-cardiac adverse effects and complex pharmacokinetics that limit widespread application. The other available drugs are not nearly as efficient for SR maintenance and have a greater risk of proarrhythmia than amiodarone. Two new antiarrhythmic drugs are on the cusp of introduction into clinical practice. Vernakalant affects several atrially expressed ion channels and has rapid unbinding Na+-channel blocking action along with promising efficacy for AF conversion to SR. Dronedarone is an amiodarone derivative with an electrophysiological profile similar to its predecessor but lacking most amiodarone-associated adverse effects. Furthermore, dronedarone has shown benefits for important clinical endpoints, including cardiovascular mortality in specific AF populations, the first AF-suppressing drug to do so in prospective randomized clinical trials. Agents that modulate non-ionic current targets (termed 'upstream' therapies) may help to modify the substrate for AF maintenance. Among these, drugs such as angiotensin II type 1 (AT1) receptor antagonists, immunosuppressive agents or HMG-CoA reductase inhibitors (statins) deserve mention. Finally, drugs that block atrial-selective ion-channel targets such as the ultra-rapid delayed rectifier current (IKur) and the acetylcholine-regulated K+-current (IKACh) are presently in development. The introduction of novel antiarrhythmic agents for the management of AF may eventually improve patient outcomes. The potential value of a variety of other novel therapeutic options is currently under active investigation. |
6,673 | Assessment of atrial electromechanical coupling characteristics in patients with ankylosing spondylitis. | The aim of this study was to evaluate atrial conduction abnormalities obtained by Doppler tissue imaging (DTI) and electrocardiogram analysis in ankylosing spondylitis (AS) patients.</AbstractText>A total of 40 patients with AS (22 males /18 females, 37.82 +/- 10.22 years), and 42 controls (22 males/20 females, 35.74 +/- 9.98 years) were included. Systolic and diastolic left ventricular (LV) functions were measured by using conventional echocardiography and DTI. Interatrial and intraatrial electromechanical coupling (PA) intervals were measured with DTI. P-wave dispersion (PD) was calculated from the 12-lead electrocardiogram.</AbstractText>Atrial electromechanical coupling at the left lateral mitral annulus (PA lateral) was significantly delayed in AS patients (61.65 +/- 7.81 vs 53.69 +/- 6.75 ms, P < 0.0001). Interatrial (PA lateral - PA tricuspid), intraatrial electromechanical coupling intervals (PA septum - PA tricuspid), maximum P-wave (Pmax) duration, and PD were significantly longer in AS patients (23.50 +/- 7.08 vs 14.76 +/- 5.69 ms, P < 0.0001; 5.08 +/- 5.24 vs 2.12 +/- 2.09 ms, P = 0.001; 103.85 +/- 6.10 vs 97.52 +/- 6.79 ms, P < 0.0001; and 48.65 +/- 6.17 vs 40.98 +/- 5.37 ms, P < 0.0001, respectively). Reflecting LV diastolic function mitral A-wave and E/A, mitral E-wave deceleration time (DT), Am and Em/Am were significantly different between the groups (P < 0.05). We found a significant correlation between interatrial electromechanical coupling interval with PD (r = 0.536, P < 0.01). Interatrial electromechanical coupling interval was positively correlated with DT (r = 0.422, P < 0.01) and inversely correlated with E/A (r =-0.263, P < 0.05) and Em/Am (r =-0.263, P < 0.05).</AbstractText>This study shows that atrial electromechanical coupling intervals and PD are delayed, and LV diastolic functions are impaired in AS patients.</AbstractText> |
6,674 | Atrioventricular node ablation is not a prerequisite for cardiac resynchronization therapy in patients with chronic atrial fibrillation. | In drug-refractory heart failure, cardiac resynchronization therapy (CRT) is an established method in patients with sinus rhythm, severe reduced ejection fraction and broad QRS. Heart failure is known as a predisposition for atrial fibrillation (AF). However, the putative impact of atrioventricular node (AVN) ablation in chronic AF and CRT remains unclear. The aim of this study was to elucidate the effects of CRT in patients with chronic AF and the requirement for AVN ablation.</AbstractText>A total of 100 patients were included in the retrospective study, 64 with sinus rhythm (SR) and 36 with chronic AF with a mean duration of 2.8 +/- 0.5 years. Clinical parameters, QRS duration and echocardiographic parameters were compared at baseline and after a follow-up of 11 +/- 0.34 months in patients with SR and in 27 patients with chronic AF who received optimized medication to control ventricular rate and nine patients who underwent an AVN ablation.</AbstractText>Baseline characteristics between patients with SR or AF in the presence or absence of AVN ablation were comparable. In each group, a significant improvement of NYHA class, ejection fraction could be observed, with an analogous reduction of QRS duration and a diminished left ventricular end-diastolic dimension after 11 +/- 0.34 months of CRT.</AbstractText>The present results demonstrate a comparable improvement in left ventricular function and functional capacity in all treated groups. In conclusion, AVN ablation is not a prerequisite for CRT in patients with severe heart failure and chronic AF.</AbstractText> |
6,675 | Cardiac resynchronization therapy in heart failure patients: an update. | Heart failure continues to be a major public health problem with high morbidity and mortality rates, despite the advances in medical treatment. Advanced heart failure patients have severe persistent symptoms and a poor quality of life. Cardiac resynchronization therapy (CRT), an invasive therapy which involves synchronized pacing of both right and left ventricles, improves ventricular conduction delay and left ventricular performance. Several clinical trials of CRT in medically refractory heart failure patients with wide QRS (> 120 ms), left ventricular ejection fraction <or=35% and New York Heart Association (NYHA) class III and IV have shown improved quality of life, NYHA class, left ventricular ejection fraction and reduced mortality. About 30% of heart failure patients who receive CRT do not respond to treatment. Mechanical dyssynchrony may play a role in identifying patients who may respond better to CRT treatment. However, recent large scale clinical trials PROSPECT and RethinQ have challenged this concept. The role of CRT in heart failure patients with narrow QRS (< 120 ms), NYHA class I and II, atrioventricular nodal ablation in patients with atrial fibrillation and triple site pacing are evolving. Our review discusses the current evidence, indications, upcoming trials and future directions. |
6,676 | Candesartan cilexetil in the treatment of chronic heart failure. | The prevalence of heart failure is ever increasing around the world, particularly due to aging populations. Despite improvements in treatment over the last 20 years, the prognosis for heart failure remains poor. Among the treatments recommended for chronic heart failure, angiotensin-converting enzyme (ACE) inhibitors and beta-blockers are crucial, provided of course that they are not contraindicated. However, angiotensin II receptor blockers (ARBs) can also be a beneficial treatment option. Candesartan is a particular ARB, characterized by a strong binding affinity to the angiotensin II type 1 receptor and slow dissociation. The benefits of candesartan have been demonstrated by the CHARM programme, which showed that candesartan significantly reduces the incidence of cardiovascular death, hospital admissions for decompensated heart failure, and all-cause mortality in chronic heart failure patients with altered left ventricular systolic function, when added to standard therapies or as an alternative to ACE inhibitors when these are poorly tolerated. Furthermore, candesartan can protect against myocardial infarction, atrial fibrillation and diabetes. Tolerance to candesartan is good, but blood pressure and serum potassium and creatinine levels must be monitored. |
6,677 | Experimental evaluation of the JenaClip transcatheter aortic valve. | Transcatheter techniques of aortic valve replacement are a treatment option for valvular heart disease in high-risk surgical candidates. We evaluated a self-expanding valve system with a novel mechanism of fixation in an experimental setting in an acute animal model and ex vivo in aortic root specimens.</AbstractText>A self-expanding nitinol stent containing a pericardial tissue valve was implanted in a transapical approach in 15 sheeps. The valve was introduced under fluoroscopic guidance through a 22F sheath by means of a specially designed delivery catheter. Deployment was performed on the beating heart without cardiopulmonary bypass or rapid ventricular pacing and facilitated by positioning feelers anchoring the device to the native aortic cusps. To investigate release and anchoring of the device during retrograde implantation, the stent was also implanted in aortic root specimens obtained from an autopsy series.</AbstractText>In animal experiments, stent deployment was primarily successful in 12 (80%) animals. Positioning feelers facilitated implantation by confirming the correct implantation plane of the stent and anchoring to the native aortic cusps. If primary location was not satisfactory the stent was retracted into the catheter and repositioned. After successful implantation no significant changes of hemodynamics were observed. Two animals (13%) developed ventricular fibrillation early in this experimental series due to displacement of one positioning element into a coronary ostium, major regurgitation was observed in two animals. Ex vivo evaluation of the device in aortic root specimens proved feasibility of stent release and leaflet fixation; ex vivo implantation was successful in all cases.</AbstractText>In this study, we demonstrate feasibility of a leaflet-fixation device in nondiseased aortic valves. The JenaClip provides an effective concept of fixation with positioning feelers that allows exact positioning without outflow obstruction and anchoring the valve to the native leaflets. Further studies are necessary to investigate this concept in diseased aortic valves.</AbstractText>2009 Wiley-Liss, Inc.</CopyrightInformation> |
6,678 | Interventional treatment of structural heart disease. | Transcatheter therapy of structural heart disease is advancing rapidly. Due to the less invasive approach, transcatheter techniques have replaced surgery as standard procedure for atrial septal defect and patent foramen ovale closure. Evolving interventional techniques allow treatment of paravalvular leaks, ventricular septal defects and valve replacement. Until recently, therapy for these diseases was limited to patients in whom severe comorbidities lead to contraindications to surgery. Techniques to treat heart failure caused by left ventricular aneurysms or to prevent cardioembolic stroke by percutaneous occlusion of the left atrial appendage in patients with atrial fibrillation are emerging. This article reviews current indications and recent developments in interventional treatment of structural heart disease. |
6,679 | Multivessel spontaneous coronary artery dissection in a postpartum woman treated with multiple drug-eluting stents. | Multivessel spontaneous coronary artery dissection is a very rare cause of myocardial ischemia. Its optimal treatment is not yet well defined and is usually tailored to clinical features. We report a case of a postpartum woman with multivessel spontaneous coronary artery dissection and acute myocardial infarction, in whom the drug-eluting stenting of the only alleged 'culprit' vessel did not prevent the propagation of dissection from another vessel. Although the recommendations drawn from a single case report are not conclusive, we believe that when there is a multivessel spontaneous coronary artery dissection in a setting of acute myocardial infarction, all dissected coronary segments should be treated using stents. |
6,680 | One-year follow-up and convalescence evaluated by nuclear medicine studies and 24-hour holter electrocardiogram in 11 patients with myocardial injury due to a blunt chest trauma. | There are few reports on long-term convalescence with regard to cardiac injury caused by blunt chest trauma. Nuclear medicine study of the heart (NMSH) in the early stages of injury is reportedly superior to detect the correlation between injury and fatal arrhythmia. Therefore, we prospectively performed NMSH and Holter electrocardiogram (ECG) in the early and chronic stages for a cardiac injury patient, and we longitudinally examined the recovery process and the occurrence of fatal arrhythmia.</AbstractText>A total of 202 patients with blunt chest trauma were admitted to our hospital between April 2006 and January 2007. Of 65 patients who were diagnosed with cardiac injury by ECG, a myocardial enzyme, or cardiac ultrasonography, 11 were enrolled in this study because they agreed to outpatient visiting for regular examinations for 1 year. NMSH showed positive findings in 6 of the 11 patients in the acute period of <1 month. Twelve months later, five patients improved but still exhibited protracted cardiac damage without complete recovery. Among the six patients in whom NMSH showed positive findings, Holter ECG indicated an abnormal finding in two patients in the acute period and in four patients in the chronic period, and detected one patient with a nonsustained ventricular tachycardia in the chronic period.</AbstractText>Cardiac injuries may exacerbate cardiac functions and lead to fatal arrhythmia during the chronic period. Therefore, evaluating recovery for at least 12 months after myocardial damage is necessary to prevent sudden cardiac death.</AbstractText> |
6,681 | Mitochondrial benzodiazepine receptors mediate cardioprotection of estrogen against ischemic ventricular fibrillation. | The cardioprotective effects of estrogen remain controversial in clinical practice. Previous reports have shown that cardioprotective mechanisms converge on the mitochondria, but the role of mitochondria in estrogen's actions on cardiac arrhythmias is unclear. Here, we report that stimulation or inhibition of mitochondrial benzodiazepine receptors (mBzR) affected ventricular fibrillation (VF) almost in an "all-or-none" manner in an in vitro rat heart model of ischemic VF. Low concentrations of estrogen did not provide antiarrhythmic effects; however, the combination of mBzR activator and estrogen reduced VF incidence in hearts from either gender. Such synergistic actions also enabled cardiomyocytes to resist metabolic stress-induced intracellular [Ca(2+)](i) overload. Ligand binding experiments revealed that estrogen itself did not affect mBzR activity under basal conditions but promoted its up-regulation under myocardial ischemia. Our results suggest that mBzR may be an important molecule for ischemic arrhythmia and may act as a molecular switch for estrogen's antiarrhythmic effects. This finding provides a clue for elucidating the conflicting results regarding estrogen's cardiac effects in clinical studies and also suggests potential new strategies for hormone treatment in the female population. |
6,682 | [Potentially lethal cardiac side effects caused by psychiatric drugs]. | The objective of this article is to analyze some of the potentially lethal cardiac side effects of psychiatric drugs and to contribute with the necessary instruments to diagnose and treat them properly. Prolongation of the QT interval caused by most of antipsychotics is discussed, focusing on those drugs with greater risk: pimozide, thioridazine, ziprasidone and sertindole. The QT interval prolongation is a risk marker of arrhythmias like the torsade de pointes, a polymorphic arrhythmia that produces dizziness, syncope, ventricular fibrillation and sudden death. Arrhythmias caused by lithium are also considered. Even though they are unusual, they constitute the most common cardiac effect of treatment with this drug. Miocarditis and cardiomyopathy, although infrequent cardiac muscle diseases, are catastrophic but potentially reversible complications, mainly associated with clozapine. Last but not least, the diagnosis and clinical management of these adverse effects is reviewed. |
6,683 | Defibrillation probability and impedance change between shocks during resuscitation from out-of-hospital cardiac arrest. | Technical data now gathered by automated external defibrillators (AEDs) allows closer evaluation of the behavior of defibrillation shocks administered during out-of-hospital cardiac arrest. We analyzed technical data from a large case series to evaluate the change in transthoracic impedance between shocks, and to assess the heterogeneity of the probability of successful defibrillation across the population.</AbstractText>We analyzed a series of consecutive cases where AEDs delivered shocks to treat ventricular fibrillation (VF) during out-of-hospital cardiac arrest. Impedance measurements and VF termination efficacy were extracted from electronic records downloaded from biphasic AEDs deployed in three EMS systems. All patients received 200J first shocks; second shocks were 200J or 300J, depending on local protocols. Results presented are median (25th, 75th percentiles).</AbstractText>Of 863 cases with defibrillation shocks, 467 contained multiple shocks because the first shock failed to terminate VF (n=61) or VF recurred (n=406). Defibrillation efficacy of subsequent shocks was significantly lower in patients that failed to defibrillate on first shock than in patients that did defibrillate on first shock (162/234=69% vs. 955/1027=93%; p<0.0001). The failed VF terminations were distributed heterogeneously across the population; 5% of patients accounted for 71% of failed shocks. Shock impedance decreased by 1% [0%, 4%] and peak current increased by 1% [0%, 4%] between 200J first and 200J second shocks. Shock impedance decreased 4% [2%, 6%] and current increased 27% [25%, 29%] between 200J first and 300J second shocks. In all 499 pairs of same-energy consecutive shocks, impedance changed by less than 1% in 226 (45%), increased >1% in 124 (25%) and decreased >1% in 149 (30%).</AbstractText>Impedance change between consecutive shocks is minimal and inconsistent. Therefore, to increase current of a subsequent shock requires an increase of the energy setting. Distribution of failed shocks is far from random. First shock defibrillation failure is often predictive of low efficacy for subsequent shocks.</AbstractText> |
6,684 | The fentanyl/etomidate-anaesthetised beagle (FEAB) dog: a versatile in vivo model in cardiovascular safety research. | The purpose of conducting cardiovascular safety pharmacology studies is to investigate the pharmacological profiles of new molecular entities (NMEs) and provide data that can be used for optimization of a possible new drug, and help make a selection of NMEs for clinical development. An anaesthetised dog preparation has been used for more than two decades by our department to measure multiple cardiovascular and respiratory parameters and to evaluate different scientific models, leading to more in-depth evaluation of drug-induced cardiovascular effects. An anaesthetic regime developed in house (induction with lofentanil, scopolamine and succinylcholine, and maintenance with fentanyl and etomidate) gives us a preparation free of pain and stress, with minimal effects on the cardiovascular system. This anaesthetic regime had minimal influences on circulating catecholamine levels, on the baroreflex sensitivity, and on all measured basal parameters compared to conscious dogs. All parameters were stable for at least 3 h, with acceptable tolerance intervals, evaluated over 99 safety studies with 3 vehicle treatments (saline, 10% and 20% hydroxypropyl-beta-cyclodextrin). This translates into a highly sensitive model for detecting possible drug-induced effects of NMEs with different mechanisms of action such as: Ca-, Na-, I(Kr)-, I(Ks)-channel blockers, K- and Ca-channel activators, alpha1- and beta-agonists, and muscarinic antagonists. Fentanyl in combination with etomidate is a successful anaesthetic regime in humans [Stockham, R.J., Stanley, T.H., Pace, N.L., King, K., Groen, F. & Gillmor, S.T. (1987). Induction of anaesthesia with fentanyl or fentanyl plus etomidate in high-risk patients. Journal of Cardiothoracic Anesthesia. 1(1), 19-23.]. In the anaesthetised dog, QT correction factors (Van de Water correction and body temperature correction) and risk factors (total, short-term and long-term instability) have been evaluated, using this regime [Van de Water, A., Verheyen, J., Xhonneux, R. & Reneman, R. (1989). An improved method to correct the QT interval of the electrocardiogram for changes in heart rate. Journal of Pharmacological Methods, 22, 207-217.; van der Linde, H.J., Van Deuren, B., Teisman, A., Towart, R. & Gallacher, D.J. (2008). The effect of changes in core body temperature on the QT interval in beagle dogs: A previously ignored phenomenon, with a method for correction. British Journal of Pharmacology, 154, 1474-1481.; van der Linde, H.J., Van de Water, A., Loots, W., Van Deuren, B., Lu, H.R., Van Ammel, K., et al. (2005) A new method to calculate the beat-to-beat instability of QT duration in drug-induced long QT in anaesthetised dogs. Journal of Pharmacological and Toxicological Methods, 52, 168-177.]. Furthermore, this anaesthetic protocol has been used to create different scientific models (long QT, short QT) with different specific end-points (ventricular fibrillation, adrenergic- or pause-dependent TdP) and also their specific precursors: e.g. aftercontractions, phase 2 EADs, phase 3 EADs, DADs, T-wave morphology changes, T-wave alternans, R-on-T, transmural and interventricular dispersion [Gallacher, D.J., Van de Water, A., van der Linde, H.J., Hermans, A.N., Lu, H.R., Towart, R., et al. (2007). In vivo mechanisms precipitating torsade de pointes in canine model of drug-induced long QT1 syndrome. Cardiovascular Research, 76-2, 247-256.]. This paper gives a brief overview of the stability, reproducibility, sensitivity and utility of a well-validated anaesthetised dog model. |
6,685 | Dilated cardiomyopathy with short QT interval: is it a new clinical entity? | Short QT syndrome is a rare autosomal dominant channelopathy of structurally normal hearts characterized by atrial fibrillation, ventricular arrhythmias, and sudden cardiac death. We report a case having short QT, dilated ventricles, and severe ventricular dysfunction, an unreported association so far. |
6,686 | A shock lead intentionally placed in the left ventricle. | The implantable cardioverter defibrillator is effective in reducing sudden cardiac death in high-risk patients. The implantation procedure is usually simple; however, in those patients who have congenital heart disease (CHD) placement of leads can be a challenge. In this report we present a patient with CHD where due to the complex cardiac anatomy it was decided to place the shock lead in the left ventricle. |
6,687 | Use of triple-site ventricular pacing in a patient with severe congestive heart failure and atrial fibrillation. | Cardiac resynchronization therapy (CRT) has become an accepted treatment for selected patients with drug-resistant heart failure. Data for patients in atrial fibrillation (AF) remains limited but suggests benefit in these patients too. We report the case of an 82-year-old patient with heart failure, VVIR permanent pacemaker, and permanent AF who had an upgrade to triple-site CRT implantation with good clinical response. Triple-site ventricular pacing may enhance the chance of response and LV reverse remodeling and should be considered in AF patients undergoing CRT implantation. |
6,688 | Mast cell degranulation--a mechanism for the anti-arrhythmic effect of endothelin-1? | The aim of this study was to investigate whether the previously reported anti-arrhythmic effect of endothelin-1 (ET-1) is mediated by degranulation of cardiac mast cells prior to myocardial ischaemia.</AbstractText>Male Sprague-Dawley rats received either ET-1 (1.6 nmolxkg(-1)) in the presence or absence of disodium cromoglycate (DSCG; 20 mgxkg(-1)xh(-1)) prior to coronary artery occlusion (CAO). In separate experiments rats were given compound 48/80 (50 microgxkg(-1)) to compare the effects of ET-1 with those of a known mast cell degranulator. Ischaemia-induced ventricular arrhythmias were detected through continuous monitoring of a lead I electrocardiogram. After 30 min of CAO, the hearts were removed and mast cell degranulation determined by histological analysis. A parallel series of sham groups were performed to determine the direct effects of ET-1 and compound 48/80 on mast cell degranulation in the absence of ischaemia.</AbstractText>ET-1 and compound 48/80 both exerted profound anti-arrhythmic effects, significantly reducing the total number of ventricular ectopic beats (P < 0.001) and the incidence of ventricular fibrillation (P < 0.05). These anti-arrhythmic effects were abolished by concomitant DSCG infusion prior to CAO. In sham animals ET-1 and compound 48/80 both induced mast cell degranulation (P < 0.001), an effect which was abolished by DSCG, confirming their ability to induce degranulation of mast cells.</AbstractText>These results demonstrate for the first time that when given prior to ischaemia ET-1 mediates its anti-arrhythmic effects, at least in part, via cardiac mast cell degranulation.</AbstractText> |
6,689 | Quinidine for pharmacological cardioversion of atrial fibrillation: a retrospective analysis in 501 consecutive patients. | Although quinidine has been used to terminate atrial fibrillation (AFib) for a long time, it has been recently classified to be used as a third-line-drug for cardioversion. However, these recommendations are based on a few small studies, and there are no data available of a larger modern patient population undergoing pharmacological cardioversion of AFib. Therefore, we evaluated the safety of quinidine for cardioversion of paroxysmal AFib in patients after cardiac surgery and coronary intervention.</AbstractText>In 501 consecutive patients (66 +/- 9 years, 32% women), 200-400 mg of quinidine were administered every 6 hours until cardioversion or for a maximum of 48 hours. Patients were included with QT interval < or =450 ms, ejection fraction (EF) > or =35%, and plasma potassium >4.3 mEq/L. Exclusion criteria were: unstable angina, myocardial infarction <3 months, and advanced congestive heart failure. Patients received verapamil, beta-blockers, or digitalis to slow down ventricular rate <100 bpm.</AbstractText>Quinidine therapy did not have to be stopped due to adverse drug reactions (ADR), and no significant QTc interval prolongation (Bazett and Fridericia correction) and no life-threatening ventricular arrhythmia occurred. Mean quinidine dose was 617 +/- 520 mg and 92% of the patients received verapamil or beta-blocker to decrease ventricular rate. Cardioversion was successful in 84% of patients. All ADRs were minor and transient. Multivariate analysis revealed female gender (OR 2.62, CI 1.61-4.26, P < 0.001) and EF 45-54% (OR 1.97, CI 1.15-3.36, P = 0.013) as independent risk factors for ADRs.</AbstractText>Quinidine for pharmacological cardioversion of AFib is safe and well tolerated in this subset of patients.</AbstractText> |
6,690 | Incidence of and outcomes associated with ventricular tachycardia or fibrillation in patients undergoing primary percutaneous coronary intervention. | The incidence and timing of sustained ventricular tachycardia or fibrillation (VT/VF) and its impact on outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) are poorly understood.</AbstractText>To evaluate the association of sustained VT/VF and its timing on the outcomes of patients presenting for primary PCI-an aim not prespecified in the APEX AMI trial.</AbstractText><AbstractText Label="DESIGN, SETTING, AND PATIENTS" NlmCategory="METHODS">We studied 5745 STEMI patients presenting for primary PCI at 296 hospitals in 17 countries between July 13, 2004, and May 11, 2006, from the APEX AMI trial. We categorized them into 4 groups: no VT/VF; VT/VF any time; early VT/VF, before the end of cardiac catheterization; and late VT/VF, after the end of cardiac catheterization.</AbstractText>Ninety-day total mortality.</AbstractText>VT/VF occurred in 329 STEMI patients (5.7%) presenting for primary PCI. The majority of these occurred before the end of catheterization (n = 205, 64%), and 90% occurred within 48 hours of presentation with symptoms of STEMI. Clinical outcomes were worse in patients with vs those without VT/VF (90-day mortality, 23.2% vs 3.6%; adjusted HR, 3.63; 95% CI, 2.59-5.09), and outcomes were worse if the VT/VF occurred late instead of early (90-day mortality for early VT/VF, 17.2% [adjusted HR, 2.34; 95% CI, 1.44-3.80]; for late VT/VF, 33.3% [adjusted HR, 5.59; 95% CI, 3.71-8.43]; for no VT/VF, 3.6% [referent]). In multivariate analyses, factors associated with early VT/VF included pre-PCI thrombolysis in MI (TIMI) flow grade 0 (HR, 2.94; 95% CI, 1.93-4.47), inferior infarction (HR, 2.16; 95% CI, 1.58-2.93), total baseline ST deviation (HR, 1.39; 95% CI, 1.19-1.63), creatinine clearance (HR, 0.88; 95% CI, 0.83-0.94), Killip class greater than I (HR, 1.88; 95% CI, 1.29-2.76), baseline systolic blood pressure (HR, 0.92; 95% CI, 0.87-0.98), body weight (HR, 1.16; 95% CI, 1.04-1.29), and baseline heart rate greater than 70/min (HR, 1.10; 95% CI, 1.01-1.20) (c index, 0.75). Factors related to late VT/VF were systolic blood pressure (HR, 0.83; 95% CI, 0.76-0.91), ST resolution less than 70% (HR, 3.17; 95% CI, 1.60-6.28), baseline heart rate greater than 70/min (HR, 1.20; 95% CI, 1.08-1.33), total baseline ST deviation (HR, 1.43; 95% CI, 1.14-1.79), post-PCI TIMI flow less than grade 3 (HR, 2.09; 95% CI, 1.24-3.52), pre-PCI TIMI flow grade 0 (HR, 2.12; 95% CI, 1.20-3.75), and beta-blockers less than 24 hours (HR, 0.52; 95% CI, 0.32-0.85) (c index, 0.74).</AbstractText>In this study, occurrence of VT/VF before or after the end of cardiac catheterization in patients presenting for primary PCI was associated with increased 90-day mortality.</AbstractText> |
6,691 | [Inherited cardiac diseases caused by Nav1.5 sodium channel mutations]. | Contraction of the heart is achieved through a delicately regulated conduction of electrical impulses. A pivotal element in the impulse propagation is the depolarising sodium current responsible for the initial depolarisation of the cardiomyocytes. Recent research has shown that mutations in the gene encoding the cardiac sodium channel (SCN5A) is associated with both rare forms of ventricular arrhythmia, and with the most frequent form of arrhythmia, atrial fibrillation. |
6,692 | Intracardiac thrombosis and anticoagulation therapy in cardiac amyloidosis. | Primary amyloidosis has a poor prognosis as a result of frequent cardiac involvement. We recently reported a high prevalence of intracardiac thrombus in cardiac amyloid patients at autopsy. However, neither the prevalence nor the effect of anticoagulation on intracardiac thrombus has been evaluated antemortem.</AbstractText>We studied all transthoracic and transesophageal echocardiograms of cardiac amyloid patients at the Mayo Clinic. The prevalence of intracardiac thrombosis, clinical and transthoracic/transesophageal echocardiographic risks for intracardiac thrombosis, and effect of anticoagulation were investigated. We identified 156 patients with cardiac amyloidosis who underwent transesophageal echocardiograms. Amyloidosis was the primary type (AL) in 80; other types occurred in 76 patients, including 56 with the wild transthyretin type, 17 with the mutant transthyretin type, and 3 with the secondary type. Fifth-eight intracardiac thrombi were identified in 42 patients (27%). AL amyloid had more frequent intracardiac thrombus than the other types (35% versus 18%; P=0.02), although the AL patients were younger and had less atrial fibrillation. Multivariate analysis showed that atrial fibrillation, poor left ventricular diastolic function, and lower left atrial appendage emptying velocity were independently associated with increased risk for intracardiac thrombosis, whereas anticoagulation was associated with a significantly decreased risk (odds ratio, 0.09; 95% CI, 0.01 to 0.51; P<0.006).</AbstractText>Intracardiac thrombosis occurs frequently in cardiac amyloid patients, especially in the AL type and in those with atrial fibrillation. Risk for thrombosis increased if left ventricular diastolic dysfunction and atrial mechanical dysfunction were present. Anticoagulation therapy appears protective. Timely screening in high-risk patients may allow early detection of intracardiac thrombus. Anticoagulation should be carefully considered.</AbstractText> |
6,693 | Improved patient survival using a modified resuscitation protocol for out-of-hospital cardiac arrest. | Cardiac arrest continues to have poor survival in the United States. Recent studies have questioned current practice in resuscitation. Our emergency medical services system made significant changes to the adult cardiac arrest resuscitation protocol, including minimizing chest compression interruptions, increasing the ratio of compressions to ventilation, deemphasizing or delaying intubation, and advocating chest compressions before initial countershock.</AbstractText>This retrospective observational cohort study reviewed all adult primary ventricular fibrillation and pulseless ventricular tachycardia cardiac arrests 36 months before and 12 months after the protocol change. Primary outcome was survival to discharge; secondary outcomes were return of spontaneous circulation and cerebral performance category. Survival of out-of-hospital arrest of presumed primary cardiac origin improved from 7.5% (82 of 1097) in the historical cohort to 13.9% (47 of 339) in the revised protocol cohort (odds ratio, 1.80; 95% confidence interval, 1.19 to 2.70). Similar increases in return of spontaneous circulation were achieved for the subset of witnessed cardiac arrest patients with initial rhythm of ventricular fibrillation from 37.8% (54 of 143) to 59.6% (34 of 57) (odds ratio, 2.44; 95% confidence interval, 1.24 to 4.80). Survival to hospital discharge also improved from an unadjusted survival rate of 22.4% (32 of 143) to 43.9% (25 of 57) (odds ratio, 2.71; 95% confidence interval, 1.34 to 1.59) with the protocol. Of the 25 survivors, 88% (n=22) had favorable cerebral performance categories on discharge.</AbstractText>The changes to our prehospital protocol for adult cardiac arrest that optimized chest compressions and reduced disruptions increased the return of spontaneous circulation and survival to discharge in our patient population. These changes should be further evaluated for improving survival of out-of-hospital cardiac arrest patients.</AbstractText> |
6,694 | Revolving back to the basics in cardiopulmonary resuscitation. | Since the 1970s, most of the research and debate regarding interventions for cardiopulmonary arrest have focused on advanced life support (ALS) therapies and early defibrillation strategies. During the past decade, however, international guidelines for cardiopulmonary resuscitation (CPR) have not only emphasized the concept of uninterrupted chest compressions, but also improvements in the timing, rate and quality of those compressions. In essence, it has been a ''revolution'' in resuscitation medicine in terms of ''coming full circle'' to the 1960s when basic CPR was first developed. Recent data have indicated the need for minimally-interrupted chest compressions with an accompanying emphasis toward removing rescue ventilation altogether in sudden cardiac arrest, at least in the few minutes after a sudden unheralded collapse. In other studies, transient delays in defibrillation attempts and ALS interventions are even recommended so that basic CPR can be prioritized to first restore and maintain better coronary artery perfusion. New devices have now been developed to modify, in real-time, the performance of basic CPR, during both training and an actual resuscitative effort. Several new adjuncts have been created to augment chest compressions or enhance venous return and evolving technology may now be able to identify ventricular fibrillation (VF) without interrupting chest compressions. A renewed focus on widespread CPR training for the average person has also returned to center stage with ground-breaking training initiatives including validated video-based adult learning courses that can reliably teach and enable long term retention of basic CPR skills and automated external defibrillator (AED) use. |
6,695 | Morphology discrimination criterion wavelet improves rhythm discrimination in single-chamber implantable cardioverter-defibrillators: Spanish Register of morphology discrimination criterion wavelet (REMEDIO). | Implantable cardioverter defibrillators (ICDs) are increasingly being used for treatment of ventricular tachycardia (VT)/fibrillation. Inappropriate therapy delivery remains the most frequent complication in patients with ICDs, resulting in psychological distress, proarrhythmia, and battery life reduction. We aim to determine if inappropriate therapies could be reduced by using a morphology discrimination criterion.</AbstractText>We evaluated the performance of the Wavelet morphology discrimination algorithm (Medtronic, Inc.) independently from other discrimination enhancements (rate onset and interval stability). A non-randomized, prospective, multicenter, and observational study was designed to determine the sensitivity and specificity of the new morphology criterion. Sensitivity and specificity in slow tachycardia with cycle length (CL) between 340 and 500 ms were analysed as a pre-specified secondary endpoint. A total of 771 spontaneous episodes in 106 patients were analysed. Five hundred and twenty-two episodes corresponded to true supraventricular tachycardia (SVT) with ventricular CL in the VT or FVT zone, of which 473 had therapy appropriately withheld. Of the 249 episodes of true VT/FVT, 21 were classified according to the Wavelet criteria as SVT (specificity: 90.6%; sensitivity: 91.6%). All of them were spontaneously terminated with no adverse clinical consequences. No syncopal episodes occurred. For VTs in the slowest analysed range (CL: 340-500 ms), a total of 235 episodes were studied, yielding a specificity of 95.9% and sensitivity of 83.2%.</AbstractText>Wavelet discrimination criteria in single-chamber ICDs as the sole discriminator can significantly reduce inappropriate therapy for SVT, not only in the range of VTs in the slowest analysed range (340-500 ms for this study) but also for faster VTs. No significant clinical consequences were found when the algorithm was used, but final data should prompt the use of the algorithm in combination with a high rate time-out feature.</AbstractText> |
6,696 | Intraprocedural reconstruction of the left atrium and pulmonary veins as a single navigation tool for ablation of atrial fibrillation: a feasibility, efficacy, and safety study. | Pulmonary vein (PV) isolation is a technically challenging intervention. For this reason, integration of three-dimensional imaging with computed tomography (CT) or magnetic resonance imaging (MRI) in order to enhance effectiveness and safety has been widely adopted. A novel imaging approach--intraprocedural rotational angiography and reconstruction of the left atrium and PVs--is feasible and provides high anatomic accuracy.</AbstractText>The purpose of this study was to prove the feasibility, safety, and efficacy of this imaging approach as a single navigation tool for PV isolation.</AbstractText>Forty-four patients (25 men and 19 women; age 57 +/- 11 years) with atrial fibrillation (AF) who presented for PV isolation were studied. Rotational angiography during adenosine-induced ventricular asystole was performed under sedation with propofol. The left atrium and PVs were reconstructed by three-dimensional atriography using specialized software (EP navigator prototype, Philips Medical Systems). Three-dimensional atriography was used as a single navigation tool for guiding PV isolation.</AbstractText>Of 176 PVs, 174 (99%) were isolated. Total procedural and fluoroscopy times were 192 +/- 46 minutes and 44 +/- 12 minutes, respectively. During follow-up of 6 +/- 3 months, 31 (70%) patients were free of symptoms and had no evidence of AF without any antiarrhythmic medication. MRI examination of 41 patients at 3-month follow-up excluded PV stenosis. No major complications occurred.</AbstractText>Three-dimensional atriography is a novel intraprocedural three-dimensional imaging technique that is based on rotational angiography. It can be safely and effectively used as a single navigation tool for performing PV isolation.</AbstractText> |
6,697 | Long-term prognosis after out-of-hospital cardiac arrest with/without ST elevation myocardial infarction. | To describe the 3-year survival of patients after out-of-hospital cardiac arrest (OHCA) taking into account the presence of ST-segment elevation myocardial infarction (STEMI) and evaluating prognostic factors associated with pre-hospital and hospital care.</AbstractText>Over a period of 29 months and with the aid of a questionnaire supplied to 24 rescue stations, we prospectively included 560 individuals (415 men; aged 16-97 years, median 68) for whom cardio-pulmonary resuscitation (CPR) for OHCA of confirmed cardiac etiology was attempted.</AbstractText>Of 149 hospitalized individuals, 28.2% survived 1 year and 25.5% survived 3 years after OHCA. In the subgroup of patients with STEMI (26 individuals; 17.5%), 57.7% survived 1 year and 53.9% survived 3 years. In the subgroup of patients without STEMI (n=123), 22% survived 1 year and 19.5% survived 3 years. The strongest predictors for long-term survival by logistic regression analysis were: age under 70 years, ventricular fibrillation as initial rhythm, CPR without atropine, and STEMI. OHCA occurrence at a public place was an indicator of better survival in the subgroup with STEMI. In the subgroup of patients without STEMI, long-term angiotensin-converting enzyme inhibitor treatment, CPR without atropine, a Glasgow Coma Scale upon hospital admission over 3, no presence of cardiogenic shock, and no manifestations of postanoxic encephalopathy (Fisher's exact test, chi(2) test) were indicators of better survival.</AbstractText>Among 560 individuals with "primary cardiac" etiology OHCA and initiation of professional CPR, 8% survived 1 year and 7% survived 3 years. A higher survival rate among patients with STEMI was documented.</AbstractText> |
6,698 | [Postpartum hemorrhage: an observational study of 21,726 deliveries in 28 months]. | To describe the management of severe postpartum hemorrhage.</AbstractText>Prospective observational study from July 2005 to November 2007 in women who were admitted to the recovery unit of a tertiary referral hospital due to postpartum hemorrhage. We analyzed incidence, prevalence, morbidity, mortality, and associated risk factors.</AbstractText>The study included 21,726 deliveries (124 with severe bleeding). Postpartum hemorrhage was more common after an instrumental delivery (odds ratio [OR], 4.54) and after a cesarean delivery (OR, 2.86). The risk factors identified in the study population were multiple gestation pregnancy and fetal death. One patient died due to disseminated intravascular coagulation. The main causes of bleeding were uterine atony (45.2%) followed by vaginal tearing (26.6%). Treatment was provided using packed red blood cells in 96.8% of the patients, fibrinogen in 49.2%, prothrombin complex in 7.25% and activated factor VII in 3.2%. Selective arterial embolization was performed in 10.5% of the cases (success rate, 84.6%) and hysterectomy was required in 13.7%. The main complications were need for postoperative mechanical ventilation (11.3%), myocardial ischemia (4%), pulmonary edema (4.8%), acute renal failure (8.9%), ventricular fibrillation (0.8%), and death (0.8%).</AbstractText>The incidence of severe postpartum hemorrhage in patients treated at our hospital is low, as is the mortality rate. Use of fibrinogen is common and provides good results. Angiographic embolization is very effective, though the percentage of hysterectomies is still high. Multiple gestation pregnancy and fetal death are associated risk factors.</AbstractText> |
6,699 | Augmentation index is associated with B-type natriuretic peptide in patients with paroxysmal atrial fibrillation. | B-type natriuretic peptide (BNP) levels have been shown to be elevated in patients with paroxysmal atrial fibrillation (PAF); however, the underlying mechanisms have not been fully elucidated. Earlier, we reported that an increase in the augmentation index (AI), which is an index of wave reflection and arterial stiffness, is associated with PAF. In this study, we investigate the relationship between the BNP level and AI in patients with PAF. We enrolled 92 patients with a history of PAF and 90 age- and gender-matched individuals without PAF. AI was calculated using applanation tonometry of the radial artery when all patients were on sinus rhythm. Plasma BNP levels were measured simultaneously. An arterial stiffness parameter, the cardio-ankle vascular index (CAVI), was also evaluated. The increased AI in patients with PAF correlated with the elevation of the BNP level (r=0.47, P<0.01). When PAF patients were classified into tertiles on the basis of the BNP level, the left atrial volume index, left ventricular mass index, AI and CAVI increased, and mitral annular e' velocity (e'), as an index of left ventricular diastolic pressure, decreased with BNP tertiles. AI was also associated with e' and left ventricular mass index. Multiple regression analysis showed that the AI in PAF patients independently correlated with BNP levels. This study showed that AI was an independent correlate of the BNP level in PAF patients. Left ventricular diastolic dysfunction, which linked to an increase in arterial stiffness, may be involved in the elevated BNP level. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.