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5,100 | Biomarkers in atrial fibrillation, ventricular arrhythmias, and sudden cardiac death. | Cardiac arrhythmias including atrial fibrillation, ventricular tachycardia, and ventricular fibrillation are important causes of cardiovascular morbidity and mortality. Although they usually occur in the setting of structural heart disease, these arrhythmias can be the primary manifestation of subclinical cardiovascular disease and have deleterious consequences including stroke, heart failure, and death. Investigational efforts have focused on developing risk stratification algorithms and diagnostic methods to identify patients who are most likely to sustain cardiac arrhythmias and benefit from early pharmacologic and interventional therapies. This review highlights important clinical and translational studies that identify potential biological markers to predict the onset of cardiac arrhythmias and their complications. Particular focus is placed on mechanisms involving the neurohormonal system, inflammation, the renin-angiotensin-aldosterone system, and metabolic pathways. |
5,101 | Safety and performance of a system specifically designed for selective site pacing. | In the right ventricle, selective site pacing (SSP) has been shown to avoid detrimental hemodynamic effects induced by right ventricular apical pacing and, in the right atrium, to prevent the onset of atrial fibrillation and to slow down disease progression. The purpose of our multicenter observational study was to describe the use of a transvenous 4-French catheter-delivered lead for SSP in the clinical practice of a large number of centers.</AbstractText>We enrolled 574 patients in whom an implantable device was indicated. In all patients, SSP was achieved by using the Select Secure System™ (Medtronic Inc., Minneapolis, MN, USA).</AbstractText>In 570 patients, the lead was successfully implanted. In 125 patients, atrial SSP was performed: in 75 (60%) the lead was placed in the interatrial septum, in 31 (25%) in the coronary sinus ostium, and in 19 (15%) in the Bachman bundle. Ventricular SSP was undertaken in 138 patients: in 105 (76%) the high septal right ventricular outflow tract (RVOT) position was paced, in seven (5%) the high free-wall RVOT, in 25 (18%) the low septal RVOT, and in one (1%) the low free-wall RVOT. In the remaining 307 patients, the His zone was paced: in 87 (28%) patients, direct His-bundle pacing and in 220 (72%) patients para-hisian pacing was achieved. Adequate pacing parameters and a lead-related complication rate of 2.6% were recorded during a follow-up of 20 ± 10 months.</AbstractText>Our results demonstrated that many sites, in the right atrium, in the right ventricle, and in His-bundle region, can be paced using the Select Secure System™.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,102 | Dynamic QT/RR relationship in post-myocardial infarction patients with and without cardiac arrest. | Changes in QT interval dynamicity may be associated with susceptibility to ventricular fibrillation (VF) after myocardial infarction (MI). We tested the hypothesis that dynamic QT/RR relationship might differ between post-MI patients with and without a history of VF. We also evaluated the influence of negative T-waves on the assessment of QT/RR relationship.</AbstractText>We reviewed Holter recordings from 37 post-MI patients resuscitated from VF not associated with new MI (VF group) and 30 patients after MI without known sustained ventricular arrhythmias (control group). With an automated computerized program, we measured QT interval dynamicity as the mean QT/RR slope and as the maximal QT/RR slope determined at stable heart rates.</AbstractText>The mean QT/RR slope was 0.20 ± 0.08 in control group and 0.15 ± 0.09 in VF group (p=0.01) whereas corresponding maximal QT/RR slope values were 0.42 ± 0.20 and 0.33 ± 0.18 (p=0.01), respectively. Thirteen control patients (43%) and 22 VF patients (59%) showed only negative or both positive and negative T-waves (p=0.45). Mean QT/RR slope values were similar irrespective of T-wave polarity whereas maximal QT/RR slopes were steeper in cases with both positive and negative T-waves. Cases showing T-waves of both positive and negative polarity exhibited greatest intersubject variability of both QT/RR slope values.</AbstractText>Lower mean QT/RR slope may be associated with a risk of VF after MI. A detailed assessment and definition of differing T-wave polarities is essential in evaluating the QT/RR relation in post-MI patients.</AbstractText> |
5,103 | Emergency medical services transport decisions in posttraumatic circulatory arrest: are national practices congruent? | To catalog the 9-1-1 emergency medical services (EMS) transport practices for posttraumatic circulatory arrest patients (PTCAPs) in the majority of the nation's largest municipalities and to compare those practices to guidelines recommended by the National Association of EMS Physicians (NAEMSP) and American College of Surgeons Committee on Trauma (ACSCOT).</AbstractText>A survey was conducted in 33 of the nation's largest cities primarily to determine whether or not individual EMS systems transport PTCAPs to hospitals and, if so, whether or not the initial electrocardiographic (ECG) rhythm or mechanism of injury affected those transport decisions.</AbstractText>All 33 cities (100%) responded. Seven (21%) indicated that EMS would transport an "asystolic blunt trauma patient" emergently or "leave the transport decision to paramedic judgment" despite NAEMSP-ACSCOT guidelines to terminate resuscitation in such cases. Likewise, 15 (46%) of the 33 EMS agencies would transport "asystolic penetrating trauma patients" emergently. Similarly, 27 (82%) would transport penetrating injury patients and 20 (61%) would transport blunt trauma patients with persistent ECG activity but no palpable pulses. However, only five systems had policies that included a minimum ECG heart rate criterion for transport, and all agencies that monitor ECG (n = 32) would transport PTCAPs found with ventricular fibrillation.</AbstractText>Many of the nation's highest volume EMS systems transport certain PTCAPs emergently, contrary to NAEMSP-ACSCOT guidelines to terminate resuscitative efforts in such cases. Reasons for these discrepancies should be evaluated to help better delineate applicable consensus guidelines for large urban EMS agencies.</AbstractText> |
5,104 | History and current trends in sudden cardiac arrest and resuscitation in adults. | Cardiac arrest occurs when organized cardiac contractility ceases and circulation stops. During cardiac arrest, electrical activity may be abnormal or absent, and the rhythm documented can be ventricular fibrillation, pulseless ventricular tachycardia, pulseless electrical activity, or asystole. It has been estimated that 300 000 sudden cardiac arrests occur each year in the United States, with 75% (225,000) occurring out-of-hospital and 25% (75,000) occurring in-hospital. A similar number occur in Europe each year. The 3-phase model of cardiac arrest, which proposes that a cardiac arrest progresses through distinct phases as time elapses, helps inform research and clinical care by providing a framework for improving outcomes from cardiac arrest. Early in an arrest, during the electrical phase, defibrillation is paramount. The circulatory phase begins after 4 to 5 minutes, and interventions to optimize circulation become of primary importance. When an arrest is prolonged, lasting for ≥10 minutes, the patient passes into the metabolic phase, in which significant metabolic derangements have accrued and start to dominate arrest physiology. If return of spontaneous circulation occurs during this phase, significant injury to diverse organs may have occurred, producing a critical illness known as post-cardiac arrest syndrome. The post-cardiac arrest syndrome has been recognized as a unique entity requiring unique therapies for successful management. Recent advances in cardiac arrest care include cardiocerebral resuscitation and the use of therapeutic hypothermia to treat comatose survivors of cardiac arrest. |
5,105 | Usefulness of tissue Doppler imaging to predict arrhythmic events in adults with repaired tetralogy of Fallot. | Adults with repaired tetralogy of Fallot (TOF) may be at risk for progressive right ventricular (RV) dilatation and dysfunction, which is commonly associated with arrhythmic events. In frequently volume-overloaded patients with congenital heart disease, tissue Doppler imaging (TDI) is particularly useful for assessing RV function. However, it is not known whether RV TDI can predict outcome in this population.</AbstractText>To evaluate whether RV TDI parameters are associated with supraventricular arrhythmic events in adults with repaired TOF.</AbstractText>We studied 40 consecutive patients with repaired TOF (mean age 35 +/- 11 years, 62% male) referred for routine echocardiographic exam between 2007 and 2008. The following echocardiographic measurements were obtained: left ventricular (LV) ejection fraction, LV end-systolic volume, LV end-diastolic volume, RV fractional area change, RV end-systolic area, RV end-diastolic area, left and right atrial volumes, mitral E and A velocities, RV myocardial performance index (Tei index), tricuspid annular plane systolic excursion (TAPSE), myocardial isovolumic acceleration (IVA), pulmonary regurgitation color flow area, TDI basal lateral, septal and RV lateral peak diastolic and systolic annular velocities (E' 1, A' 1, S' 1, E' s, A' s, S' s, E' rv, A' rv, S' rv), strain, strain rate and tissue tracking of the same segments. QRS duration on resting ECG, total duration of Bruce treadmill exercise stress test and presence of exercise-induced arrhythmias were also analyzed. The patients were subsequently divided into two groups: Group 1--12 patients with previous documented supraventricular arrhythmias (atrial tachycardia, fibrillation or flutter) and Group 2 (control group)--28 patients with no previous arrhythmic events. Univariate and multivariate analysis was used to assess the statistical association between the studied parameters and arrhythmic events.</AbstractText>Patients with previous events were older (41 +/- 14 vs. 31 +/- 6 years, p = 0.005), had wider QRS (173 +/- 20 vs. 140 +/- 32 ms, p = 0.01) and lower maximum heart rate on treadmill stress testing (69 +/- 35 vs. 92 +/- 9%, p = 0.03). All patients were in NYHA class I or II. Clinical characteristics including age at corrective surgery, previous palliative surgery and residual defects did not differ significantly between the two groups. Left and right cardiac chamber dimensions and ventricular and valvular function as evaluated by conventional Doppler parameters were also not significantly different. Right ventricular strain and strain rate were similar between the groups. However, right ventricular myocardial TDI systolic (Sa: 5.4+2 vs. 8.5 +/- 3, p = 0.004) and diastolic indices and velocities (Ea, Aa, septal E/Ea, and RV free wall tissue tracking) were significantly reduced in patients with arrhythmias compared to the control group. Multivariate linear regression analysis identified RV early diastolic velocity as the sole variable independently associated with arrhythmic history (RV Ea: 4.5 +/- 1 vs. 6.7 +/- 2 cm/s, p = 0.01). A cut-off for RV Ea of < 6.1 cm/s identified patients in the arrhythmic group with 86% sensitivity and 59% specificity (AUC = 0.8).</AbstractText>Our results suggest that TDI may detect RV dysfunction in patients with apparently normal function as assessed by conventional echocardiographic parameters. Reduction in RV early diastolic velocity appears to be an early abnormality and is associated with occurrence of arrhythmic events. TDI may be useful in risk stratification of patients with repaired tetralogy of Fallot.</AbstractText> |
5,106 | Emerging clinical role of ranolazine in the management of angina. | Chronic stable angina is an exceedingly prevalent condition with tremendous clinical, social, and financial implications. Traditional medical therapy for angina consists of beta-blockers, calcium channel blockers, and nitrates. These agents decrease myocardial oxygen demand and ischemia by reducing heart rate, lowering blood pressure, and/or optimizing ventricular loading characteristics. Unique in its mechanism of action, ranolazine is the first new antianginal agent approved for use in the US for chronic angina in over 25 years. By inhibiting the late inward sodium current (I(Na)), ranolazine prevents pathologic intracellular calcium accumulation that leads to ischemia, myocardial dysfunction, and electrical instability. Ranolazine has been proven in multiple clinical trials to reduce the symptoms of angina safely and effectively and to improve exercise tolerance in patients with symptomatic coronary heart disease. These benefits occur without reduction in heart rate and blood pressure or increased mortality. Although ranolazine prolongs the QT(c), experimental data indicate that ranolazine may actually be antiarrhythmic. In a large acute coronary syndrome clinical trial, ranolazine reduced the incidence of supraventricular tachycardia, ventricular tachycardia, new-onset atrial fibrillation, and bradycardic events. Additional benefits of ranolazine under investigation include reductions in glycosylated hemoglobin levels and improved left ventricular function. Ranolazine is a proven antianginal medication in patients with symptomatic coronary heart disease, and should be considered as an initial antianginal agent for those with hypotension or bradycardia. |
5,107 | Predisposing factors and incidence of newly diagnosed atrial fibrillation in an urban African community: insights from the Heart of Soweto Study. | Little is known about the incidence and clinical characteristics of newly diagnosed atrial fibrillation/flutter (AF) in urban Africans in epidemiological transition.</AbstractText>This observational cohort study was carried out in the Chris Hani Baragwanath Hospital in Soweto South Africa. A clinical registry captured detailed clinical data on all de novo cases of AF presenting to the Cardiology Unit during the period 2006-2008.</AbstractText>Overall, 246 of 5328 cardiac cases (4.6%) presented with AF (estimated 5.6 cases/100 000 population/annum). Mean age was 59±18 years and the majority were of African descent (n=211, 86%) and/or female (n=150, 61%). Men were more than twice as likely to smoke (OR 2.88, 95% CI 1.92 to 4.04) than women, but women were twice as likely to be obese (OR 1.80, 95% CI 1.28 to 2.52) than men. Lone AF occurred in 22 (8.9%) cases, while concurrent valve disease and/or functional valvular abnormality occurred in 107 cases (44%). Overall, 171 cases (70%) presented with uncontrolled AF (ventricular rate >90 beats/min) with no sex-based differences. Common co-morbidities were any form of heart failure (56%) and rheumatic heart disease (21%). Women with AF were more likely to present with hypertensive heart failure (OR 2.37, 95% CI 1.24 to 4.54) but less likely to present with a dilated cardiomyopathy (OR 0.42, 95% CI 0.23 to 0.76) or coronary artery disease (OR 0.38, 95% CI 0.14 to 1.02) than men. Mean overall CHADS(2) score (in 195 non-rheumatic cases) was 1.51±0.91 and, despite a similar age profile, women had higher scores than men (1.73±0.94 vs 1.24±0.78; p<0.0001).</AbstractText>These unique data suggest that urban Africans in Soweto develop AF at a relatively young age. Conventional strategies used to manage and treat AF need to be carefully evaluated in this setting.</AbstractText> |
5,108 | Factors associated with pulseless electric activity versus ventricular fibrillation: the Oregon sudden unexpected death study. | Corresponding with a continuing decline in the prevalence of sudden cardiac arrest cases presenting with ventricular fibrillation (VF), there has been a significant rise in the prevalence of pulseless electrical activity (PEA). Given significantly lower survival from PEA versus VF, we comprehensively investigated PEA correlates by incorporating first-responder data with lifetime clinical history information.</AbstractText>In the Portland, Ore, metropolitan area (population ≈1 million), cases of out-of-hospital sudden cardiac arrest who underwent attempted resuscitation were identified prospectively (2002-2007). Those presenting with PEA versus VF and asystole were compared with χ² tests, ANOVA, and logistic regression. A total of 1277 cases aged ≥18 years underwent resuscitation by first responders (mean age, 65±16 years; 67% male). Presenting arrhythmia was VF in 48%, PEA in 25%, and asystole/other in the remainder. Compared with VF cases, PEA cases were older (mean age, 68 versus 63 years; P=0.0002), more likely to be female (37% versus 26%; P=0.0008), and less likely to survive to hospital discharge (6% versus 25%; P<0.0001). A history of syncope was strongly associated with PEA (odds ratio, 2.6; confidence interval, 1.3 to 5.3) after adjustment for age, gender, response time, and arrest circumstances. Black race was also independently associated with PEA (odds ratio, 2.6; confidence interval, 1.3 to 5.4). Pulmonary disease and female gender were significant factors associated with PEA (P for interaction=0.04). In a subgroup analysis of resting ECGs (n=391), there were no differences in cardiac clinical history or prevalence of cardiac conduction system disease (PEA, 31.6% versus VF, 32.2%; P=0.48).</AbstractText>PEA cases had a significantly higher prevalence of syncope in their lifetime, with other correlates, including black race, that were distinct from VF cases. Potential mechanistic links between syncope and future manifestation with PEA warrant further exploration.</AbstractText> |
5,109 | Role of family history of sudden death in risk stratification and prevention of sudden death with implantable defibrillators in hypertrophic cardiomyopathy. | The selection of patients with hypertrophic cardiomyopathy (HC) for the primary prevention of sudden death (SD) with implantable cardioverter-defibrillators (ICDs) has been determined by the assessment of 5 risk factors. We examined one of these markers, the family history of HC-related SD in first-degree relatives, for which few data are available. The rate of appropriate ICD interventions was assessed in 177 consecutive patients with HC (63% men, age 45 ± 14 years) who had undergone prophylactic implantation at 2 tertiary centers, according to the identification of ≥ 1 risk markers. During a follow-up period of 4.6 ± 3 years, 25 patients (14%) had experienced appropriate ICD interventions for ventricular tachycardia/fibrillation. The patients with a risk profile that included a family history of SD experienced interventions at a similar rate (3.7/100 person-years) as the patients without a family history of SD (3.1/100 person-years, p = 0.2). The rate and frequency of appropriate ICD interventions in 42 patients who had undergone implantation solely because of a family history of SD was 2.2/100 person-years (4/42, 10%), similar to that for patients with one risk factor other than SD family history (3.4%/100 person-years; 7/50, 14%; p = 0.2) and patients with multiple risk factors with (4.5/100 person-years; 9/49, 18%) and without (3.5/100 person-years; 5/36, 14%) a family history of SD (p = 0.8). In conclusion, a family history of SD is an important risk marker in patients with HC. Patients receiving ICDs for primary prevention because of a family history of HC-related SD, whether as an isolated risk factor or combined with other markers, experienced rates of appropriate ICD discharge comparable to that of other patient subsets with increased risk. |
5,110 | Dronedarone for the treatment of atrial fibrillation and atrial flutter. | This paper presents a summary of the evidence review group (ERG) report on the clinical effectiveness and cost-effectiveness of dronedarone for the treatment of atrial fibrillation (AF) or atrial flutter based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal process. The population considered in the submission were adult clinically stable patients with a recent history of or current non-permanent AF. Comparators were the current available anti-arrhythmic drugs: class 1c agents (flecainide and propafenone), sotalol and amiodarone. Outcomes were AF recurrence, all-cause mortality, stroke, treatment discontinuations (due to any cause or due to adverse events) and serious adverse events. The main evidence came from four phase III randomised controlled trials, direct and indirect meta-analyses from a systematic review, and a synthesis of the direct and indirect evidence using a mixed-treatment comparison. Overall, the results from the different synthesis approaches showed that the odds of AF recurrence appeared statistically significantly lower with dronedarone and other anti-arrhythmic drugs than with non-active control, and that the odds of AF recurrence are statistically significantly higher for dronedarone than for amiodarone. However, the results for outcomes of all-cause mortality, stroke and treatment discontinuations and serious adverse events were all uncertain. A discrete event simulation model was used to evaluate dronedarone versus antiarrhythmic drugs and standard therapy alone. The incremental cost-effectiveness ratio of dronedarone was relatively robust and less than 20,000 pounds per quality-adjusted life-year. Exploratory work undertaken by the ERG identified that the main drivers of cost-effectiveness were the benefits assigned to dronedarone for all-cause mortality and stroke. Dronedarone is not cost-effective relative to its comparators when the only effect of treatment is a reduction in AF recurrences. In conclusion, uncertainties remain in the clinical effectiveness and cost-effectiveness of dronedarone. In particular, the clinical evidence for the major drivers of cost-effectiveness (all-cause mortality and stroke), and consequently the additional benefits attributed in the economic model to dronedarone compared to other anti-arrhythmic drugs are highly uncertain. The final guidance, issued by NICE on 25 August 2010, states that: Dronedarone is recommended as an option for the treatment of non-permanent atrial fibrillation only in people: whose atrial fibrillation is not controlled by first-line therapy (usually including beta-blockers), that is, as a second-line treatment option, and who have at least one of the following cardiovascular risk factors: - hypertension requiring drugs of at least two different classes, diabetes mellitus, previous transient ischaemic attack, stroke or systemic embolism, left atrial diameter of 50 mm or greater, left ventricular ejection fraction less than 40% (noting that the summary of product characteristics [SPC] does not recommend dronedarone for people with left ventricular ejection fraction less than 35% because of limited experience of using it in this group) or age 70 years or older, and who do not have unstable New York Heart Association (NYHA) class III or IV heart failure. Furthermore, 'People who do not meet the criteria above who are currently receiving dronedarone should have the option to continue treatment until they and their clinicians consider it appropriate to stop'. |
5,111 | Dronedarone for atrial fibrillation? | Atrial fibrillation (AF) is the commonest sustained heart arrhythmia and is associated with significant morbidity and mortality, with, for example, one in five of all strokes being attributable to the condition. Dronedarone (pronounced dro-ne-da-roan) (Multaq--sanofi-aventis) is a new anti-arrhythmic drug related to the established anti-arrhythmic amiodarone. It is licensed for use in clinically stable adult patients with a history of, or current, non-permanent AF to prevent recurrence of AF or to lower ventricular rate. Here we review its role in the management of patients with non-permanent AF. |
5,112 | Effect of early changes in functional geometry of left ventricular contraction on the development of ventricular fibrillation during acute myocardial ischaemia. An experimental study. | The early appearance of ventricular fibrillation (VF) following acute myocardial infarction (MI) is associated with adrenergic effects and electrical interactions although some early "mechanical" changes may also occur. The aim of the present experimental study was to examine whether early changes in the functional geometry of left ventricular (LV) contraction may be associated with ventricular arrhythmias occurring during the first 120min of MI.</AbstractText>In 11 swine left anterior descending (LAD) coronary artery ligation was performed. Aortic flow, LV end-diastolic pressure (LVEDP), LV long and short axis lengths were measured and their fractional shortening (FS) was calculated before and during the initial 120min period of MI.</AbstractText>LV long axis FS and aortic flow decreased (p<0.001) whereas LVEDP increased (p<0.01) in all 11 animals within 30min following LAD ligation. LV long and short axis lengths and LV short axis FS did not change significantly. VF occurred in 5 of the 11 animals within this 30min period. LV short axis FS decreased (p<0.05) in all 5 animals prior to VF and increased (p<0.05) in all 6 animals without VF. In 3 of the 6 animals that had no VF during the initial 30min VF occurred later. Similarly, LV short axis FS decreased prior to VF in all those 3 animals. LV short axis FS did not decrease in any of the remaining 3 swine without VF during the same period of time.</AbstractText>Early changes in the functional geometry of LV contraction, in the form of a reduction of LV short axis FS, are associated with a greater incidence of VF in experimental acute MI.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,113 | [Viable myocardium detecting by CARTO voltage mapping in swine model of acute myocardial infarction]. | To evaluate the accuracy and practicability of detecting viable myocardium by CARTO voltage mapping in swine model of acute myocardial infarction (MI).</AbstractText>MI was induced in 13 anesthetized swines via occluding the distal of left anterior descending coronary arteries by angioplasty balloon for 60-90 minutes. The viable myocardium detection by CARTO voltage mapping was made after reconstruction of the left ventricle using CARTO and the results were compared with TTC staining. The standard of CARTO voltage to detect viable myocardium was 0.5 - 1.5 mV while viable myocardium showed pink color by TTC staining.</AbstractText>Eleven out of 13 swines survived the operation and 2 swines died of ventricular fibrillation at 45 and 65 minutes post ischemia. Left ventricle was divided into 16 segments and 176 segments from 11 swines were analyzed. Viable myocardium detected by CARTO voltage mapping was identical as identified by TTC staining (Kappa = 0.816, P < 0.001). Taken the TTC result as standard, the sensitivity, specificity and accuracy rate of CARTO voltage mapping are 71.8%, 96.5% and 90.9% respectively.</AbstractText>CARTO voltage mapping could be used as a reliable tool to detect viable myocardium in this model.</AbstractText> |
5,114 | Prognostic value of serial B-type natriuretic peptide measurement in asymptomatic organic mitral regurgitation. | Optimal timing of surgery is crucial in mitral regurgitation (MR) to avoid excess mortality and morbidity. The role of brain-type natriuretic peptide (BNP) in this setting remains controversial. We evaluated the value of serial BNP measurements for early prediction of deterioration in asymptomatic MR.</AbstractText>Eighty-seven consecutive asymptomatic patients with severe organic MR, normal left ventricular (LV) function (ejection fraction ≥ 60%, end-systolic diameter index < 26 mm/m²), systolic pulmonary artery pressure (sPAP) <50 mmHg, and no atrial fibrillation underwent clinical assessment, echocardiography, and measurement of BNP and N-terminal pro-BNP (NT-proBNP) at 6-month intervals. The primary endpoint was the development of symptoms and/or LV dysfunction. The secondary endpoint was the occurrence of atrial fibrillation or sPAP ≥ 50 mmHg. Over a mean follow-up of 786 ± 454 days, 20 patients reached the primary endpoint and 5, the secondary endpoint. By univariate analysis, age, BNP, NT-proBNP, and sPAP were significant predictors of reaching the primary endpoint during the 6 months following testing, whereas LV function and dimensions were not. By multivariate analysis, only BNP (P = 0.03) and sPAP (P = 0.04) remained independent predictors. When secondary endpoints were additionally considered, results remained unchanged. Receiver operator curve analysis yielded AUC-values of 0.90, 0.84, and 0.80 for BNP, NT-proBNP, and sPAP, but 0.60 and 0.57 for left ventricular ejection fraction and end-systolic diameter. The negative predictive value for normal neurohormone levels and sPAP was high (98-100%). A BNP of 145 pg/mL had a positive predictive value of 36%.</AbstractText>Brain natriuretic peptide and NT-proBNP independently predict outcome in asymptomatic MR. Serial measurements may help to improve timing of surgery. Low plasma levels with their high negative predictive values appear to be particularly helpful by identifying low-risk individuals.</AbstractText> |
5,115 | Radiofrequency ablation for persistent atrial fibrillation in patients with advanced heart failure and severe left ventricular systolic dysfunction: a randomised controlled trial. | To determine whether or not radiofrequency ablation (RFA) for persistent atrial fibrillation in patients with advanced heart failure leads to improvements in cardiac function.</AbstractText>Patients were recruited from heart failure outpatient clinics in Scotland.</AbstractText>Patients with advanced heart failure and severe left ventricular dysfunction were randomised to RFA (rhythm control) or continued medical treatment (rate control). Patients were followed up for a minimum of 6&emsp14;months.</AbstractText>Change in left ventricular ejection fraction (LVEF) measured by cardiovascular MRI.</AbstractText>22 patients were randomised to RFA and 19 to medical treatment. In the RFA group, 50% of patients were in sinus rhythm at the end of the study (compared with none in the medical treatment group). The increase in cardiovascular magnetic resonance (CMR) LVEF in the RFA group was 4.5±11.1% compared with 2.8±6.7% in the medical treatment group (p=0.6). The RFA group had a greater increase in radionuclide LVEF (a prespecified secondary end point) than patients in the medical treatment group (+8.2±12.0% vs +1.4±5.9%; p=0.032). RFA did not improve N-terminal pro-B-type natriuretic peptide, 6&emsp14;min walk distance or quality of life. The rate of serious complications related to RFA was 15%.</AbstractText>RFA resulted in long-term restoration of sinus rhythm in only 50% of patients. RFA did not improve CMR LVEF compared with a strategy of rate control. RFA did improve radionuclide LVEF but did not improve other secondary outcomes and was associated with a significant rate of serious complications.</AbstractText> |
5,116 | Heart rhythm disturbances in the neonatal alloxan-induced diabetic rat. | Diabetic patients show a higher incidence of cardiac arrhythmias, including ventricular fibrillation and sudden death. Their electrocardiograms may show several alterations from normal patterns, many of them related to the QT. Various diastolic and systolic abnormalities are frequently reported in diabetic patients, and the severity of the abnormalities depend on the patients' age and the duration of diabetes. The aim of this experimental study has been to clarify the progressive effects on heart rhythm in neonatal alloxan (ALX) (induced at 5 days of age) diabetic male rats. Cardiac biopotential data were acquired in vivo with a biotelemetry system. After an overnight fast blood glucose in diabetic rats, compared to age-matched controls, was elevated before and at 60, 120 and 180min after a glucose challenge at 2 and 8 months of age. Heart rate and heart rate variability were modestly reduced and QT interval modestly prolonged in diabetic rats, compared to controls, at 2, 6 and 8 months of age. There was also an age-dependent decline in heart rate and prolongation in QT interval. At 8 months heart rate was 296±8bpm in diabetic compared to 311±10bpm in controls and heart rate variability was 27±3bpm in diabetic rats compared to 32±4bpm in controls. Physical activity was significantly reduced in diabetic rats, compared to controls, at 6 and 8 months of age. Body temperature was modestly reduced in diabetic rats, compared to controls, at 2, 6 and 8 months. In conclusion, the neonatal ALX-induced diabetes mellitus was associated with disturbances in heart rate, heart rate variability, QT interval which in turn may be associated with changes in physical activity and body temperature. |
5,117 | Does prearrest adrenergic integrity affect pressor response? A comparison of epinephrine and vasopressin in a spontaneous ventricular fibrillation swine model. | Coronary perfusion pressure (CPP) during resuscitation from cardiac arrest has been shown to correlate with return of spontaneous circulation. Adrenergic blockade of beta-1 and alpha-1 receptors is common in the long-term management of ischemic heart disease and congestive heart failure. We sought to compare the CPP response to vasopressin vs. epinephrine in a swine model of cardiac arrest following pre-arrest adrenergic blockade.</AbstractText>Eight anesthetized and instrumented swine were administered 0.1mg epinephrine and arterial pressure and heart rate response were measured. An infusion of labetalol was then initiated and animals periodically challenged with epinephrine until adrenergic blockade was confirmed. The left anterior descending coronary artery was occluded to produce ventricular fibrillation (VF). After 7min of untreated VF, mechanical chest compressions were initiated. After 1min of compressions, 1mg epinephrine was given while CPP was recorded. When CPP values had returned to pre-epinephrine levels, 40U of bolus vasopressin was given. Differences in CPP (post-vasopressor-pre-vasopressor) were compared within animals for the epinephrine and vasopressin response and with eight, non-adrenergically blocked, historical controls using Bayesian statistics with a non-informative prior.</AbstractText>The CPP response following epinephrine was 15.1mmHg lower in adrenergically blocked animals compared to non-adrenergically blocked animals (95% Highest Posterior Density [HPD] 2.9-27.2mmHg lower). CPP went up 18.4mmHg more following vasopressin when compared to epinephrine (95% HPD 8.2-29.1mmHg). The posterior probability of a higher CPP response from vasopressin (vs. epinephrine) in these animals was 0.999.</AbstractText>Pre-arrest adrenergic blockade blunts the CPP response to epinephrine. Superior augmentation of CPP is attained with vasopressin under these conditions.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,118 | SCN5A mutation is associated with early and frequent recurrence of ventricular fibrillation in patients with Brugada syndrome. | Mutations in SCN5A are reportedly linked to Brugada syndrome (BS), but recent observations suggest that they are not necessarily associated with ventricular fibrillation (VF) in BS patients. Therefore, the clinical importance of SCN5A mutations in BS patients was examined in the present study.</AbstractText> The 108 BS patients were examined for SCN5A mutations and various parameters were compared between patients with and without mutations. An implantable cardioverter defibrillator (ICD) was implanted in 49 patients and a predictor of appropriate ICD shock was investigated. The existence of a SCN5A mutation was not associated with initial VF episodes (21.7% vs 20.0%, P=0.373). In the secondary prevention group, appropriate shock-free survival rate was significantly lower in patients with spontaneous type 1 ECG than in those without (41.1% vs 85.7% at 2 years, P=0.014). The appropriate shock-free survival rate was also significantly lower in patients with SCN5A mutations than in those without (28.6% vs 83.3% at 1 year, P=0.040). Appropriate shock was more frequent in patients with SCN5A mutations than in those without (6.6±6.2 vs 1.7±3.0, P=0.007).</AbstractText>SCN5A mutations are associated with early and frequent VF recurrence, but not with initial VF episodes. This is the first report on the genotype-phenotype interaction and clinical significance of this mutation.</AbstractText> |
5,119 | Real-time lesion assessment using a novel combined ultrasound and radiofrequency ablation catheter. | Assessment of lesion size and transmurality is currently via indirect measures. Real-time image assessment may allow ablation parameters to be titrated to achieve transmurality and reduce recurrences due to incomplete lesions.</AbstractText>The purpose of this study was to visualize lesion formation in real time using a novel combined ultrasound and externally irrigated ablation catheter.</AbstractText>In an in vivo open-chest sheep model, 144 lesions were delivered in 11 sheep to both the atria and the ventricles, while lesion development was monitored in real time. Energy was delivered for a minimum of 15 seconds and a maximum of 60 seconds, with a range of powers, to achieve different lesion depths. Twenty-two lesions were also delivered endocardially. The ultrasound appearance was assessed and compared with the pathological appearance by four independent blinded observers.</AbstractText>For the ventricular lesions (n = 126), the mean power delivered was 6.1 ± 2.0 W, with a mean impedance of 394.7 ± 152.4 Ω and with an impedance drop of 136.4 ± 100.1 Ω. Lesion depths varied from 0 to 10 mm, with a median depth of 3.5 mm. At tissue depths up to 5 mm, changes in ultrasound contrast correlated well (r = 0.79, R(2) = 0.62) with tissue necrosis. The depth of ultrasound contrast correlated poorly with the depth of the zone of hemorrhage (r = 0.33, R(2) = 0.11), and impedance change correlated poorly with lesion depth (r = 0.29, R(2) = 0.08).</AbstractText>Real-time lesion assessment using high-frequency ultrasound integrated into an ablation catheter is feasible and allows differentiation between true necrosis and hemorrhage. This may lead to safer and more efficient power delivery, allowing more effective lesion formation.</AbstractText>Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,120 | Modeling the effect of Kv1.5 block on the canine action potential. | A wide range of ion channels have been considered as potential targets for pharmacological treatment of atrial fibrillation. The Kv1.5 channel, carrying the I(Kur) current, has received special attention because it contributes to repolarization in the atria but is absent or weakly expressed in ventricular tissue. The dog serves as an important animal model for electrophysiological studies of the heart and mathematical models of the canine atrial action potential (CAAP) have been developed to study the interplay between ionic currents. To enable more-realistic studies on the effects of Kv1.5 blockers on the CAAP in silico, two continuous-time Markov models of the guarded receptor type were formulated for Kv1.5 and subsequently inserted into the Ramirez-Nattel-Courtemanche model of the CAAP. The main findings were: 1), time- and state-dependent Markov models of open-channel Kv1.5 block gave significantly different results compared to a time- and state-independent model with a downscaled conductance; 2), the outcome of Kv1.5 block on the macroscopic system variable APD(90) was dependent on the precise mechanism of block; and 3), open-channel block produced a reverse use-dependent prolongation of APD(90). This study suggests that more-complex ion-channel models are a prerequisite for quantitative modeling of drug effects. |
5,121 | Dronedarone: evidence supporting its therapeutic use in the treatment of atrial fibrillation. | Dronedarone, a benzofuran derivative with a structure similar to amiodarone, has been developed as a potential therapy for patients with atrial fibrillation.</AbstractText>To review the published evidence regarding the efficacy and safety of dronedarone use in patients with atrial fibrillation.</AbstractText>Available evidence suggests that dronedarone 400 mg orally twice daily can lengthen the time to and decrease the overall recurrence of atrial fibrillation compared with placebo. Dronedarone may reduce risk of mortality and cardiovascular hospitalization. Patients with atrial fibrillation receiving dronedarone had improved ventricular rate control compared with patients receiving placebo. Dronedarone is associated with few serious adverse events except, notably, in patients with decompensated heart failure.</AbstractText>Dronedarone may have a role in rate and rhythm control for patients with atrial fibrillation. Dronedarone can reduce unique, but potentially serious, end points in patients with atrial fibrillation. Despite this, the exact role of dronedarone in the management of patients with atrial fibrillation continues to emerge. It remains uncertain if dronedarone should be considered a primary treatment strategy for atrial fibrillation. Dronedarone should not be administered to patients with decompensated heart failure.</AbstractText>Dronedarone is a unique drug that may serve a key role to treat patients with atrial fibrillation.</AbstractText> |
5,122 | Distinct restitution properties in vagally mediated atrial fibrillation and six-hour rapid pacing-induced atrial fibrillation. | The atrial potential duration (APD) restitution has been suggested to play an important role in ventricular fibrillation; however, its role in atrial fibrillation (AF) has not been determined. This study sought to investigate the APD restitution properties in two different AF models: vagally mediated AF and 6-h rapid atrial pacing-induced AF.</AbstractText>Twenty anaesthetized open-chest dogs were assigned to Group I, vagally mediated AF (n= 8) or Group II, 6-h rapid atrial pacing-induced AF (n= 12). In both groups, the monophasic APD was subsequently recorded at multiple pulmonary vein and atrial sites. The APD restitution curve was constructed using a dynamic pacing protocol and determined by plotting each APD(90) against the preceding diastolic interval at incremental atrial pacing rates at eight sites. In Group I, vagal stimulation significantly shortened the APD(90), flattened the APD restitution curve (slopes <1), and suppressed the APD alternans at each site, while increasing the AF inducibility and duration (P<0.05 for all). In Group II, 6-h rapid pacing-induced APD shortening steepened the restitution curves (slopes >1), facilitated the APD alternans, and also increased the incidence and duration of AF (P< 0.05 for all). The spatial dispersion of APD restitution was significantly increased in both groups.</AbstractText>This study showed distinct atrial APD restitution properties in vagally mediated AF and 6-h rapid pacing-induced AF, indicating specific restitution kinetics in different mechanisms of AF.</AbstractText> |
5,123 | Control of action potential duration alternans in canine cardiac ventricular tissue. | Cardiac electrical alternans, characterized by a beat-to-beat alternation in action potential waveform, is a naturally occurring phenomenon, which can occur at sufficiently fast pacing rates. Its presence has been putatively linked to the onset of cardiac reentry, which is a precursor to ventricular fibrillation. Previous studies have shown that closed-loop alternans control techniques that apply a succession of externally administered cycle perturbations at a single site provide limited spatially-extended alternans elimination in sufficiently large cardiac substrates. However, detailed experimental investigations into the spatial dynamics of alternans control have been restricted to Purkinje fiber studies. A complete understanding of alternans control in the more clinically relevant ventricular tissue is needed. In this paper, we study the spatial dynamics of alternans and alternans control in arterially perfused canine right ventricular preparations using an optical mapping system capable of high-resolution fluorescence imaging. Specifically, we quantify the spatial efficacy of alternans control along 2.5 cm of tissue, focusing on differences in spatial control between different subregions of tissue. We demonstrate effective control of spatially-extended alternans up to 2.0 cm, with control efficacy attenuating as a function of distance. Our results provide a basis for future investigations into electrode-based control interventions of alternans in cardiac tissue. |
5,124 | Coronary artery bypass graft for anomalous right coronary artery. | A 27-year-old man with anomalous right coronary artery (RCA) presented with ventricular fibrillatory arrest. Computed tomography angiography revealed an anomalous RCA arising from the left sinus of Valsalva with an acute angulation at the coronary takeoff and compressed interarterial segment. This patient underwent a short saphenous vein coronary artery bypass graft to the proximal RCA and recovered uneventfully. A review of the literature and discussion of the surgical management is presented. |
5,125 | Utility of postoperative testing of implantable cardioverter-defibrillators. | Implantable cardioverter-defibrillators (ICDs) can provide life-saving therapies for ventricular arrhythmias. Arrhythmia induction and defibrillation threshold testing is often performed at implantation and postoperatively during long-term follow-up to ensure proper device function.</AbstractText>We sought to evaluate the prevalence and predictors of occult device malfunction at follow-up defibrillation testing in asymptomatic individuals. A cohort of 853 patients underwent 1,578 defibrillation tests during the 13-year study period. Defibrillation efficacy was evaluated primarily by the two-shock (2S) method, with an adequate safety margin ≥ 10 joules (J) less than the maximum energy delivered by the ICD.</AbstractText>A total of 38 testing failures requiring intervention were discovered during testing (2.4% of all tests). There were 11 ICD system failures resulting in failure to defibrillate, six with underdetection of ventricular fibrillation, and 21 clinically significant increases in defibrillation threshold. There was a higher incidence of failure in older ICD systems (1996-2002) compared to newer ICD systems (2003-2009), reaching statistical significance (3.6% vs 1.0%; P < 0.01). There were 178 subjects (20.8%) with a >20-J safety margin on previous testing, detected R waves >7.0 mV, and all system components implanted after 2003 at the time of testing who did not have any testing failures (0% vs 5.6%; P < 0.01).</AbstractText>Postoperative defibrillation testing identifies a small number of ICD malfunctions in asymptomatic individuals. ICD testing failure is seen more frequently in older systems and in those with borderline results from prior interrogation or testing. These findings suggest that serial postoperative defibrillation testing is not indicated in asymptomatic patients without suspicion for specific problems.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,126 | Greater three-dimensional ventricular lead tip separation is associated with improved outcome after cardiac resynchronization therapy. | Effective cardiac resynchronization therapy (CRT) is more likely with widely separated left ventricular (LV) and right ventricular (RV) pacing leads tips. We hypothesized that lead separation is an important factor in determining the clinical response to CRT.</AbstractText>A retrospective study of 86 consecutive patients age 71 ± 10 years, male (74%), coronary disease (71%), atrial fibrillation (23%), LV ejection fraction (22 ± 9%), QRS duration (160 ± 27 ms), New York Heart Association (NYHA) class III (81%), NYHA class IV (19%) undergoing CRT from January 2006 to September 2008. The median follow-up was 12 months and clinical response to CRT was defined as reduction of NYHA class by one or more. The three-dimensional separation between RV and LV pacing lead tips was calculated using measurements obtained from orthogonal posteroanterior and lateral chest radiographs performed the day after implantation.</AbstractText>Fifty-nine patients (69%) responded to CRT. There was a statistically significant association between increased three-dimensional lead separation and clinical response to CRT (P= 0.005). Stronger association was obtained when lead separation was corrected for cardiac size (P= 0.001). A significantly higher response rate of 88% was achieved in patients with QRS duration of 160 ms or more, and lead separation of 100 mm or more compared with 60% when lead separation was less than 100 mm and QRS duration remained the same (P = 0.027).</AbstractText>Greater three-dimensional separation of LV-to-RV leads is associated with improved response to CRT. A prospective multicenter trial is needed to assess lead separation as a predictor for response.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,127 | Termination of ventricular tachycardia by far-field stimulation in humans: a feasibility study. | Although a low-energy cardioversion (LEC) shock from an implantable cardioverter-defibrillator (ICD) can terminate ventricular tachycardia (VT), it frequently triggers ventricular fibrillation (VF) and is therefore not used in clinical practice. We tested whether a modified LEC shock with a very short duration (0.12-0.36 ms), termed "field stimulus," can terminate VT without triggering VF.</AbstractText>In 13 sedated patients with implanted ICDs, we attempted to induce VT and to terminate the arrhythmias by field stimuli during hospital predischarge tests.</AbstractText>In eight patients, 27 VT episodes were induced and treated with a total of 46 high-voltage (25-200 V) field stimuli, which terminated 11 VT episodes (41% efficacy) and never accelerated VT into VF. VT episodes slower than 230 beats per minute (bpm) (median rate) were terminated more successfully than faster arrhythmia episodes (69% vs 15%, P < 0.01). The strength of the field stimulus had no major influence on the effectiveness. We therefore postulate that suboptimal timing of field stimuli (delivered simultaneously with a sensed event in the right ventricular apex) was the main reason for failed VT terminations.</AbstractText>A short (0.12-0.36 ms), high-voltage (50-100 V) field stimulus delivered from the shock coil of an implanted ICD system can safely terminate VT, especially for VT rates below 230 bpm. We believe that it would be reasonable to test the effectiveness of automatic field-stimulus therapy from implanted ICDs in VT episodes up to 230 bpm that are not susceptible to termination by antitachycardia pacing.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,128 | Outcome of heart failure with preserved ejection fraction: a multicentre spanish registry. | Studies on clinical features, treatment and prognosis of patients with congestive heart failure (CHF) and preserved left ventricular ejection fraction (LVEF) are few and their results frequently conflicting.</AbstractText>To investigate the characteristics and long term prognosis of patients with CHF and preserved (≥ 45%) LVEF.</AbstractText>We conducted a prospective multicentre study with 4720 patients attended in 62 heart failure clinics from 1999 to 2003 in Spain (BADAPIC registry). LVEF was preserved in 30% patients. Age, female gender, prevalence of atrial fibrillation, hypertension and non-ischaemic cardiopathy were all significantly greater in patients with preserved LVEF. Mean follow-up was 40±12 months. Mortality and other cardiovascular complication rates during follow up were similar in both groups. On multivariate analysis ejection fraction was not an independent predictor for mortality. Survival at one and five years was similar in both groups (79% and 59% for patients with preserved LVEF and 78% and 57% for those with reduced LVEF, respectively).</AbstractText>In the BADAPIC registry, a high percentage of heart failure patients had preserved LVEF. Although clinical differences were seen between groups, morbidity and mortality were similar in both groups.</AbstractText> |
5,129 | Echocardiographic Brockenbrough-Braunwald-Morrow sign. | The Brockenbrough-Braunwald-Morrow sign is the paradoxical decrease in pulse pressure during the post-extrasystole beat seen in patients with hypertrophic obstructive cardiomyopathy. We present a case of intermittent left ventricular outflow tract obstruction and secondary mitral regurgitation resulting from post-extrasystolic potentiation following a premature atrial beat, demonstrating using echocardiography the mechanism behind this sign. |
5,130 | Accurate estimation of entropy in very short physiological time series: the problem of atrial fibrillation detection in implanted ventricular devices. | Entropy estimation is useful but difficult in short time series. For example, automated detection of atrial fibrillation (AF) in very short heart beat interval time series would be useful in patients with cardiac implantable electronic devices that record only from the ventricle. Such devices require efficient algorithms, and the clinical situation demands accuracy. Toward these ends, we optimized the sample entropy measure, which reports the probability that short templates will match with others within the series. We developed general methods for the rational selection of the template length m and the tolerance matching r. The major innovation was to allow r to vary so that sufficient matches are found for confident entropy estimation, with conversion of the final probability to a density by dividing by the matching region volume, 2r(m). The optimized sample entropy estimate and the mean heart beat interval each contributed to accurate detection of AF in as few as 12 heartbeats. The final algorithm, called the coefficient of sample entropy (COSEn), was developed using the canonical MIT-BIH database and validated in a new and much larger set of consecutive Holter monitor recordings from the University of Virginia. In patients over the age of 40 yr old, COSEn has high degrees of accuracy in distinguishing AF from normal sinus rhythm in 12-beat calculations performed hourly. The most common errors are atrial or ventricular ectopy, which increase entropy despite sinus rhythm, and atrial flutter, which can have low or high entropy states depending on dynamics of atrioventricular conduction. |
5,131 | Improving safety in the electrophysiology laboratory using a simple radiation dose reduction strategy: a study of 1007 radiofrequency ablation procedures. | The use of fluoroscopic screening involves exposure to ionising radiation for both patients and operators.</AbstractText>To assess the effects of radiation dose reduction manoeuvres (DRM) during radiofrequency ablation (RFA) procedures.</AbstractText>Prospective study of DRM.</AbstractText>Tertiary cardiac centre. Interventions Two DRM were combined: removal of the secondary radiation grid and programming an ultra-low pulsed fluoroscopy rate. These methods were assessed using an anthropomorphic phantom model to measure skin entrance dose rates. Procedures were classified as complex (ablation of atrial fibrillation, ventricular tachycardia or complex congenital heart disease arrhythmias) or simple (all other RFA).</AbstractText>Dose area product and screening times were compared for ablations performed before and after DRM. Equivalent doses to organs and malignancy risk were determined by computer modelling.</AbstractText>Over a 39-month period, 1007 ablation procedures were performed (631 simple, 376 complex). Radiation dose was significantly reduced after DRM for both simple (20.4±26.9 Gycm(2) vs 8.0±10.3 Gycm(2), p<0.00001) and complex ablations (63.3±50.1 Gycm(2) vs 32.8±31.7 Gycm(2), p<0.00001) with no difference in screening times. The mean lifetime risk of fatal cancer attributable to radiation exposure per million procedures was reduced from 182 to 68 for simple ablations and from 440 to 155 for complex ablations.</AbstractText>Significant reductions in radiation exposure during RFA were achieved using simple DRM, corresponding to a two-thirds reduction of the risk of excess fatal malignancy.</AbstractText> |
5,132 | The association between intra-arrest therapeutic hypothermia and return of spontaneous circulation among individuals experiencing out of hospital cardiac arrest. | Therapeutic hypothermia has been shown to improve both mortality and neurologic outcomes following pulseless ventricular tachycardia and fibrillation. Animal data suggest intra-arrest induction of therapeutic hypothermia (IATH) improves frequency of return of spontaneous circulation (ROSC). Our objective was to evaluate the association between IATH and ROSC.</AbstractText>This was a retrospective analysis of individuals experiencing non-traumatic cardiac arrest in a large metropolitan area during a 12-month period. Six months into the study a prehospital IATH protocol was instituted whereby patients received 2000ml of 4°C normal saline directly after obtaining IV/IO access. The main outcome variables were prehospital ROSC, survival to admission, and to discharge. A secondary analysis was conducted to assess the relationship between the quantity of cold saline infused and the likelihood of prehospital ROSC.</AbstractText>551 patients met inclusion criteria with all the elements available for data analysis. Rates of prehospital ROSC were 36.5% versus 26.9% (OR 1.83; 95% CI 1.19-2.81) in patients who received IATH versus normothermic resuscitation respectively. While the frequency of survival to hospital admission and discharge were increased among those receiving IATH, the differences did not reach statistical significance. The secondary analysis found a linear association between the amount of cold saline infused and the likelihood of prehospital ROSC.</AbstractText>The infusion of 4°C normal saline during the intra-arrest period may improve rate of ROSC even at low fluid volumes. Further study is required to determine if intra-arrest cooling has a beneficial effect on rates of ROSC, mortality, and neurologic function.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,133 | Novel intravascular defibrillator: defibrillation thresholds of intravascular cardioverter-defibrillator compared to conventional implantable cardioverter-defibrillator in a canine model. | An intravascular, percutaneously placed implantable defibrillator (InnerPulse percutaneous intravascular cardioverter-defibrillator [PICD]) with a right ventricular (RV) single-coil lead and titanium electrodes in the superior vena cava (SVC) and the inferior vena cava (IVC) has been developed.</AbstractText>The purpose of this study was to compare defibrillation thresholds (DFTs) of the PICD to those of a conventional implantable cardioverter-defibrillator (ICD) in canines.</AbstractText>Eight Bluetick hounds were randomized to initial placement of either a PICD or a conventional ICD. For PICD DFTs, a single-coil RV defibrillator lead was placed in the RV apex, and the device was positioned in the venous vasculature with electrodes in the SVC and IVC. With the conventional ICD, an RV lead was placed in the RV apex and an SVC coil was appropriately positioned. The ICD active can (AC) was implanted in a subcutaneous pocket formed in the left anterior chest wall and connected to the lead system. DFT was determined by a three-reversal, step up-down method to estimate the 80% success level. Two configurations were tested for the conventional ICD (#1: RV to SVC+AC; #2: RV to AC). A single configuration (RV to SVC+IVC) was evaluated for the PICD.</AbstractText>Mean PICD DFT was 14.8 ± 1.53 (SE) J. Conventional #1 configuration demonstrated mean DFT of 20.2 ± 2.45 J and #2 of 27.5 ± 1.95 J. The PICD had a significantly lower DFT than the better conventional ICD configuration (#1; mean difference 5.4 ± 2.1 J, P <.05, paired t-test, N = 8).</AbstractText>The new intravascular defibrillator had a significantly lower DFT than the conventional ICD in this canine model.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,134 | Potential proarrhythmic effect of cardiac resynchronization therapy during perioperative period: data from a single cardiac center. | Cardiac resynchronization therapy (CRT) could improve heart function, symptom status, quality of life and reduce hospitalization and mortality in patients with severe heart failure (HF) with optimal medical management. However, the possible adverse effects of CRT are often ignored by clinicians.</AbstractText>A retrospective analysis of CRT over a 6-year period was made in a single cardiac center.</AbstractText>Fifty-four patients were treated with CRT(D) device, aged (57 ± 11) years, with left ventricular ejection fraction of (32.1 ± 9.8)%, of which 4 (7%) developed ventricular tachycardia/ventricular fibrillation (VT/VF) or junctional tachycardia after operation. Except for one with frequent ventricular premature beat before operation, the others had no previous history of ventricular arrhythmia. Of the 4 patients, 3 had dilated cardiomyopathy and 1 had ischemic cardiomyopathy, and tachycardia occurred within 3 days after operation. Sustained, refractory VT and subsequent VF occurred in one patient, frequent nonsustained VT in two patients and nonparoxysmal atrioventricular junctional tachycardia in one patient. VT was managed by amiodarone in two patients, amiodarone together with beta-blocker in one patient, and junctional tachycardia was terminated by overdrive pacing. During over 12-month follow-up, except for one patient's death due to refractory heart and respiratory failure in hospital, the others remain alive and arrhythmia-free.</AbstractText>New-onset VT/VF or junctional tachycardia may occur in a minority of patients with or without prior history of tachycardia after biventricular pacing. Arrhythmia can be managed by conventional therapy, but may require temporary discontinuation of pacing. More observational studies should be performed to determine the potential proarrhythmic effect of CRT.</AbstractText> |
5,135 | Flash pulmonary edema in patients with renal artery stenosis--the Pickering Syndrome. | We report the prevalence of flash pulmonary edema in patients consecutively referred for balloon angioplasty of uni- or bilateral renal artery stenosis (PTRA), and describe the characteristics of this special fraction of the patients. We further report two unusual cases.</AbstractText>Review of medical records from 60 patients consecutively referred for uni- or bilateral PTRA from 2004-2005 in Copenhagen County.</AbstractText>Eight out of 60 patients had one or more episodes of flash pulmonary edema before PTRA. Compared with the remaining patients, they had a higher prevalence of bilateral stenosis (50% vs 27%) and coronary artery disease (75% vs 28%). However, only one of eight had severe systolic dysfunction of the left ventricle. After PTRA, two recurrences of flash pulmonary edema were observed. One was caused by severe restenosis and did not recur after aorto-renal bypass surgery. The other one was caused by rapid atrial fibrillation and did not recur after pacemaker and medical treatment.</AbstractText>Flash pulmonary edema can be observed in patients with unilateral as well as bilateral stenosis. The prognosis is usually excellent upon treatment of the stenoses. Recurrences are rare unless restenosis occurs, and therefore, regular control, e.g. by Doppler-ultrasound examination is recommended.</AbstractText> |
5,136 | [Restitution of atrial repolarization and atrial fibrillation in canine atrium]. | Electrical restitution was believed to be a determinant responsible for the stability of heart rhythm. Although numerous studies focused on the role of action potential duration restitution (APDR) in the initiation and maintenance of ventricular fibrillation (VF), the relationship between atrial APDR and atrial fibrillation (AF) has not been fully understood. This study aims to investigate the characteristics of APDR of left atrium (LA) and right atrium (Rs) in canines and the relevance to induction of AF.</AbstractText>Monophasic action potential (MAP) was recorded from LA and RA in 14 canines using the MAP recording-pacing combination catheter. APDR, plotted as action potential duration (APD) on the preceding diastolic interval (DI), was assessed by use of programmed stimulation with a single extrastimulus (S1S2) at LA and RA. Episodes of AF were recorded and analyzed.</AbstractText>APD90 was significantly shorter in the LA than that in the RA [(157.4 +/- 43.5) ms vs. (170.9 +/- 37.9) ms, P < 0.05]. The mean slope of the APDR curve by S1S2 in the LA was significantly greater than that in the RA (1.3 +/- 0.4 vs. 0.9 +/- 0.3, P < 0.05). The incidence of induced AF was significantly higher in the LA than in the RA (11/18 vs. 7/18, P < 0.05).</AbstractText>The APDR and MAP characteristics are not uniform between atrium, which may be one of the important mechanisms responsible for the initiation of AF. Heterogeneity of APDR between LA and RA might create critical gradients or a dispersion of repolarization and substrate for re-entrant arrhythmias and vulnerability to AF.</AbstractText> |
5,137 | Transaortic endoclamp for mitral valve operation through right minithoracotomy in 369 patients. | : The effects and benefits of a transaortic endoclamp for mitral valve operation through right minithoracotomy have not been established.</AbstractText>: The records were examined in 671 patients undergoing mitral valve operation using aortic cannulation through a 6-cm right minithoracotomy in the fourth intercostal space. The ascending aorta was cannulated with a 24-Fr cannula through a 12-mm port in the first intercostal space. The experience from 1998 to 2006 with aortic endoclamping (group A, N = 436) was compared with the experience from 2006 to 2009 with external aortic clamping (group B, N = 235). Aortic endoclamping was achieved with a 30 mL endoclamp introduced through the aortic cannula into the ascending aorta to provide aortic endoclamping, anterograde cardioplegia, and root venting. Percutaneous femoral venous cannulation was used.</AbstractText>: Group A and group B had similar demographics. Endoclamp availability (group A) resulted in significantly less fibrillatory arrest (no clamping) in 67 of 436 (15%) versus 104 of 235 (44%) patients in group B (P = 0.001). In patients with aortic clamping, endoclamp (group A) versus external clamp (group B) was not a determinant of clamp time or pump time. Hospital and late outcomes were not different between groups. No patient complications could be attributed to the endoclamp.</AbstractText>: Aortic endoclamping requires no more clamp or pump time than external clamping and can provide a more bloodless field than ventricular fibrillation without obstructing hardware. Aortic endoclamping is a safe alternative for mitral surgery through right minithoracotomy.</AbstractText> |
5,138 | Augmented ST-segment elevation during recovery from exercise predicts cardiac events in patients with Brugada syndrome. | The goal of this study was to evaluate the prevalence and the clinical significance of ST-segment elevation during recovery from exercise testing.</AbstractText>During recovery from exercise testing, ST-segment elevation is reported in some patients with Brugada syndrome (BrS).</AbstractText>Treadmill exercise testing was conducted for 93 patients (91 men), 46 ± 14 years of age, with BrS (22 documented ventricular fibrillation, 35 syncope alone, and 36 asymptomatic); and for 102 healthy control subjects (97 men), 46 ± 17 years of age. Patients were routinely followed up. The clinical end point was defined as the occurrence of sudden cardiac death, ventricular fibrillation, or sustained ventricular tachyarrhythmia.</AbstractText>Augmentation of ST-segment elevation ≥0.05 mV in V(1) to V(3) leads compared with baseline was observed at early recovery (1 to 4 min at recovery) in 34 BrS patients (37% [group 1]), but was not observed in the remaining 59 BrS patients (63% [group 2]) or in the 102 control subjects. During 76 ± 38 months of follow-up, ventricular fibrillation occurred more frequently in group 1 (15 of 34, 44%) than in group 2 (10 of 59, 17%; p = 0.004). Multivariate Cox regression analysis showed that in addition to previous episodes of ventricular fibrillation (p = 0.005), augmentation of ST-segment elevation at early recovery was a significant and independent predictor for cardiac events (p = 0.007), especially among patients with history of syncope alone (6 of 12 [50%] in group 1 vs. 3 of 23 [13%] in group 2) and among asymptomatic patients (3 of 15 [20%] in group 1 vs. 0 of 21 [0%] in group 2).</AbstractText>Augmentation of ST-segment elevation during recovery from exercise testing was specific in patients with BrS, and can be a predictor of poor prognosis, especially for patients with syncope alone and for asymptomatic patients.</AbstractText>Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,139 | Meta-analysis of the effectiveness and safety of catheter ablation of atrial fibrillation in patients with versus without left ventricular systolic dysfunction. | Catheter ablation is a promising therapy for atrial fibrillation (AF), but its utility in patients with left ventricular systolic dysfunction (LVSD) is uncertain. The objectives of this study were to perform a systematic review and meta-analysis of randomized and observational studies comparing the rates of recurrent AF, atrial tachycardia (AT), and complications after AF catheter ablation in those with versus without LVSD and to summarize the impact of catheter ablation on the left ventricular ejection fraction. Seven observational studies and 1 randomized trial were included (total n = 1,851). Follow-up ranged from 6 to 27 months. In those with LVSD, 28% to 55% were free of AF or AT on follow-up after 1 AF catheter ablation, increasing to 64% to 96% after a mean of 1.4 procedures. The relative risk for recurrent AF or AT in those with versus without LVSD was 1.5 (95% confidence interval 1.2 to 1.8, p <0.001) after 1 procedure and 1.2 (95% confidence interval 0.9 to 1.5, p = 0.2) after multiple procedures. No difference in complications was observed in patients with (3.5%) versus without (2.5%) heart failure (p = 0.55). After catheter ablation, those with LVSD experienced a pooled absolute improvement in the left ventricular ejection fraction of 0.11 (95% confidence interval 0.07 to 0.14, p <0.001). In conclusion, patients with and without LVSD had similar risk for recurrent AF or AT after catheter ablation, but repeat procedures were required more often in those with LVSD. Significant improvements in left ventricular ejection fractions after ablation were observed in those with LVSD. Randomized trials are needed given the limitations of present data. |
5,140 | Usefulness of vernakalant hydrochloride injection for rapid conversion of atrial fibrillation. | The objective of the present study was to assess the safety and effectiveness of vernakalant hydrochloride injection (RSD1235), a novel antiarrhythmic drug, for the conversion of atrial fibrillation (AF) or atrial flutter to sinus rhythm (SR). Patients with either AF or atrial flutter were randomized in a 1:1 ratio to receive vernakalant (n = 138) or placebo (n = 138) and were stratified by an arrhythmia duration of >3 hours to ≤7 days (short duration) and 8 to ≤45 days (long duration). The first infusion of placebo or vernakalant (3 mg/kg) was given for 10 minutes followed by a second infusion of placebo or vernakalant (2 mg/kg) 15 minutes later if the arrhythmia had not terminated. A total of 265 patients were randomized and received treatment. The primary end point was conversion of AF to SR for ≥1 minute within 90 minutes of the start of the drug infusion in the short-duration AF group. Of the 86 patients receiving vernakalant in the short-duration AF group, 44 (51.2%) demonstrated conversion to SR compared to 3 (3.6%) of the 84 in the placebo group (p <0.0001). The median interval to conversion of short-duration AF to SR in the responders given vernakalant was 8 minutes. Of the entire AF population (short- and long-duration AF), 47 (39.8%) of the 118 vernakalant patients experienced conversion of AF to SR compared to 4 (3.3%) of the 121 placebo patients (p <0.0001). Transient dysgeusia and sneezing were the most common adverse events in the vernakalant patients. One vernakalant patient who had severe aortic stenosis experienced hypotension and ventricular fibrillation and died. In conclusion, vernakalant demonstrated a rapid and high rate of conversion for short-duration AF and was well tolerated. |
5,141 | [Summary of the practice guideline 'Atrial fibrillation' (first revision) from the Dutch College of General Practitioners]. | The revised practice guideline 'Atrial fibrillation' from the Dutch College of General Practitioners provides the general practitioner with guidelines for diagnosis and management of patients with atrial fibrillation. To find patients with atrial fibrillation, it is advised to check cardiac rhythm at every blood pressure measurement. In patients over 65 years old, acceptance of atrial fibrillation with control of ventricular rate is preferred to sinus rhythm normalisation. In therapy with beta-blockers, slow release metoprolol is the drug of choice. An important goal of treatment is the prevention of thrombo-embolic complications. The choice between anticoagulants such as aspirin and coumarin derivatives is based on the CHADS2 score and determined by age (above 75 years) and comorbidity including cardiac failure, diabetes, hypertension, and previous transient ischaemic attack (TIA) or cardiovascular accident (CVA). The adequacy of antithrombotic treatment should be reassessed yearly. |
5,142 | Manual versus mechanical cardiopulmonary resuscitation. An experimental study in pigs. | Optimal manual closed chest compressions are difficult to give. A mechanical compression/decompression device, named LUCAS, is programmed to give compression according to the latest international guidelines (2005) for cardiopulmonary resuscitation (CPR). The aim of the present study was to compare manual CPR with LUCAS-CPR.</AbstractText>30 kg pigs were anesthetized and intubated. After a base-line period and five minutes of ventricular fibrillation, manual CPR (n = 8) or LUCAS-CPR (n = 8) was started and run for 20 minutes. Professional paramedics gave manual chest compression's alternating in 2-minute periods. Ventilation, one breath for each 10 compressions, was given to all animals. Defibrillation and, if needed, adrenaline were given to obtain a return of spontaneous circulation (ROSC).</AbstractText>The mean coronary perfusion pressure was significantly (p < 0.01) higher in the mechanical group, around 20 mmHg, compared to around 5 mmHg in the manual group. In the manual group 54 rib fractures occurred compared to 33 in the LUCAS group (p < 0.01). In the manual group one severe liver injury and one pressure pneumothorax were also seen. All 8 pigs in the mechanical group achieved ROSC, as compared with 3 pigs in the manual group.</AbstractText>LUCAS-CPR gave significantly higher coronary perfusion pressure and significantly fewer rib fractures than manual CPR in this porcine model.</AbstractText> |
5,143 | Noninvasive detection of left-ventricular systolic dysfunction by acoustic cardiography in atrial fibrillation. | Objectives. Assessment of left ventricular (LV) systolic function in patients with atrial fibrillation can be difficult. Acoustic cardiography provides several parameters for quantifying LV systolic function. We evaluated the ability of acoustic cardiography to detect LV systolic dysfunction in patients with and without atrial fibrillation. Design. We studied 194 patients who underwent acoustic cardiography and cardiac catheterization including measurement of angiographic ejection fraction (EF) and maximum LV dP/dt. LV systolic dysfunction was defined as LV maximum dP/dt <1600 mmHg/s. Acoustic cardiographic parameters included electromechanical activation time (EMAT) and the systolic dysfunction index (SDI). Results. Acoustic cardiography detected systolic dysfunction with high specificity and moderate sensitivity with similar performance to EF (sensitivity/specificity without afib: EMAT 30/96, SDI 40/90, EF at 35% 30/96; sensitivity/specificity with afib: EMAT 64/82, SDI 59/100, EF at 35% 45/82). Conclusions. Acoustic cardiography can be used for diagnosis of LV systolic dysfunction in atrial fibrillation. |
5,144 | Brugada syndrome associated with supraventricular tachycardia: diagnostic and therapeutic strategies. | We report the case of a patient with Brugada syndrome and a history of palpitations who presented with an episode of syncope and developed supraventricular tachycardia in the electrophysiological study. The patient was treated with radiofrequency ablation for the supraventricular tachycardia and an implantable cardioverter defibrillator for the Brugada syndrome. At 18 months following implantation of the defibrillator an electrical storm with ventricular fibrillation episodes occurred followed by appropriate discharges of the defibrillator. |
5,145 | Risk stratification in individuals with the Brugada type 1 ECG pattern without previous cardiac arrest: usefulness of a combined clinical and electrophysiologic approach. | Risk stratification in individuals with type 1 Brugada electrocardiogram (ECG) pattern (type 1 ECG) for primary prevention of sudden death (SD).</AbstractText>Three hundred and twenty patients (258 males, median age 43 years) with type 1 ECG were enrolled. No patient had previous cardiac arrest. Fifty-four per cent of patients had a spontaneous and 46% a drug-induced type 1 ECG. One-third had syncope, two-thirds were asymptomatic. Two hundred and forty-five patients underwent electrophysiologic study (EPS) and 110 patients received an implantable cardiac defibrillator (ICD). During follow-up [median length 40 months (IQ20-67)], 17 patients had major arrhythmic events (MAE) (14 resuscitated ventricular fibrillation (VF) and three SD). Both a spontaneous type 1 ECG and syncope significantly increased the risk (2.6 and 3.0% event rate per year vs. 0.4 and 0.8%). Major arrhythmic events occurred in 14% of subjects with positive EPS, in no subjects with negative EPS and in 5.3% of subjects without EPS. All MAE occurred in subjects who had at least two potential risk factors (syncope, family history of SD, and positive EPS). Among these patients, those with spontaneous type 1 ECG had a 30% event rate.</AbstractText>(1) In subjects with the Brugada type 1 ECG, no single clinical risk factor, nor EPS alone, is able to identify subjects at highest risk; (2) a multiparametric approach (including syncope, family history of SD, and positive EPS) helps to identify populations at highest risk; (3) subjects at highest risk are those with a spontaneous type 1 ECG and at least two risk factors; (4) the remainder are at low risk.</AbstractText> |
5,146 | [Changes in myocardial connexin 43 during ventricular fibrillation]. | To observe changes in connexin 43 (Cx43) after ventricular fibrillation (VF) and the effects of rotigaptide (ZP123) on Cx43.</AbstractText>Thirty domestic pigs were randomly assigned to three groups (10 in each group): sham group, model group and ZP123 group. VF was induced by an 80 V AC transthoracic shock for 5 seconds with the use of subcutaneous needles. Before the induction of VF, animals in ZP123 group were administered with ZP123 (1 μg/kg bolus+10 μg×kg(-1)×h(-1) dissolved in 50 ml normal saline and pumped for 15 minutes ). Those in model group received 50 ml normal saline pumped for 15 minutes. For pigs in sham group VF was not induced and no fluid was given. After 8 minutes of VF, animals were euthanized and myocardial tissues were harvested along the long axis of each left ventricular free wall. Immunofluorescence combined with laser scanning confocal microscope was used to detect the distribution of Cx43. Western blotting was used for quantitative determination of Cx43 protein expression.</AbstractText>Immunofluorescence signals for Cx43 in sham group were strong and regularly distributed. In model group, Cx43 signals were weak and distributed in heterogeneity, while in ZP123 group, Cx43 signals were enhanced and their distribution were much more orderly. Compared with sham group, the percentage area and the optical densities (A value) of Cx43 fluorescence signals and Cx43 protein expression were significantly decreased in model group [the percentage area: (0.64±0.36)% vs.(1.27±0.19)%, A value: 15 201± 2 613 vs. 30 634±4 975, Cx43 protein expression: 0.72±0.08 vs. 0.97±0.07, all P<0.05]. The level of Cx43 expression in ZP 123 group [the percentage area (0.96±0.16)%, A value 22 100±4 404, Cx43 protein expression 0.82±0.04] was much higher than model group (all P<0.05).</AbstractText>During VF, down-regulation of myocardial Cx43 expression occurred, which could be attenuated by administration of ZP123.</AbstractText> |
5,147 | Intracoronary autologous CD34+ stem cell therapy for intractable angina. | <AbstractText Label="BACKGROUND/OBJECTIVES" NlmCategory="OBJECTIVE">A large number of patients with coronary artery disease experience angina that is not suitable for revascularization and is refractory to conventional medical therapy. Laboratory and preclinical studies have provided evidence for the safety and potential efficacy of autologous CD34+ stem cell therapies as treatment for angina. Clinical studies investigating intramyocardial transplantation of autologous CD34+ stem cells by catheter injection for patients with refractory angina show that this is safe and feasible. It remains unclear whether intracoronary infusion of CD34+ stem cells exerts beneficial effects in patients with angina as well. We addressed this question with a controlled clinical trial by enrolling 112 patients with refractory angina. Previous trials have investigated the safety and beneficial effects of CD34+ cells isolated from granulocyte colony-stimulating factor-mobilized peripheral blood; in our trial, we isolated CD34+ cells directly from the patient's bone marrow.</AbstractText>One hundred and twelve patients with diffuse triple-vessel disease and Canadian Cardiovascular Society class III or IV angina were enrolled in a double-blind, randomized (1:1), placebo-controlled study. Patients received optimal medical treatment but were not candidates for mechanical revascularization (percutaneous coronary intervention or coronary artery bypass grafting). Fifty-six patients (27 women and 29 men aged 42-80 years) were enrolled in the treatment group, and 56 patients (28 women and 28 men aged 43-80 years) who received optimal medical treatment and intracoronary saline injections were enrolled in the placebo control group. Bone marrow was collected from all enrolled patients at a volume of 120-150 ml each in both groups. Selections of CD34+ cells were performed by a CE-marked device approved by the Security, Food and Drug Administration of China. Coronary angiography had been performed before enrollment in this study.</AbstractText>No myocardial infarction was observed during intracoronary infusion. The intracoronary infusion of cells or saline did not result in cardiac enzyme elevation, cardiac perforation or pericardial effusion. No arrhythmia, such as ventricular tachycardia or ventricular fibrillation, was induced by intracoronary infusion. No serious adverse events occurred in either group. The reduction in the frequency of angina episodes per week 3 and 6 months after infusion was significantly higher in the treatment group (-14.6 ± 4.8 at 3 months and -15.6 ± 4.0 at 6 months) than in the control group (-4.5 ± 0.3 and -3.0 ± 1.2, respectively; p < 0.01). Other efficacy parameters such as nitroglycerine usage, exercise time and the Canadian Cardiovascular Society class also showed an improvement in the treatment group compared to the control group. A significant improvement in myocardial perfusion was noted in the treatment group compared to the control group, as measured by single-photon emission computed tomography.</AbstractText>This randomized trial investigating intracoronary infusion of autologous CD34+ cells in patients with intractable angina shows the safety and feasibility of this therapy and provides evidence for efficacy.</AbstractText>Copyright © 2010 S. Karger AG, Basel.</CopyrightInformation> |
5,148 | Chronic occlusion of the left main coronary artery: importance of collaterals. | Chronic occlusion of the left coronary artery is an infrequent finding in patients undergoing coronary angiography. These patients usually present symptoms of angina or heart failure. We describe a patient who was training regularly without cardiac symptoms until ventricular fibrillation suddenly occurred during a long-distance run. A chronic left main stem occlusion with well-developed right-to-left coronary collaterals was demonstrated by angiography. Up to this event, the collateral flow had been sufficient to allow physical exercise at a high performance level without symptoms. The patient later underwent coronary bypass surgery and recovered completely. |
5,149 | Comparison between transcatheter and surgical prosthetic valve implantation in patients with severe aortic stenosis and reduced left ventricular ejection fraction. | Patients with severe aortic stenosis and reduced left ventricular ejection fraction (LVEF) have a poor prognosis with conservative therapy but a high operative mortality when treated surgically. Recently, transcatheter aortic valve implantation (TAVI) has emerged as an alternative to surgical aortic valve replacement (SAVR) for patients considered at high or prohibitive operative risk. The objective of this study was to compare TAVI and SAVR with respect to postoperative recovery of LVEF in patients with severe aortic stenosis and reduced LV systolic function.</AbstractText>Echocardiographic data were prospectively collected before and after the procedure in 200 patients undergoing SAVR and 83 patients undergoing TAVI for severe aortic stenosis (aortic valve area ≤1 cm(2)) with reduced LV systolic function (LVEF ≤50%). TAVI patients were significantly older (81±8 versus 70±10 years; P<0.0001) and had more comorbidities compared with SAVR patients. Despite similar baseline LVEF (34±11% versus 34±10%), TAVI patients had better recovery of LVEF compared with SAVR patients (ΔLVEF, 14±15% versus 7±11%; P=0.005). At the 1-year follow-up, 58% of TAVI patients had a normalization of LVEF (>50%) as opposed to 20% in the SAVR group. On multivariable analysis, female gender (P=0.004), lower LVEF at baseline (P=0.005), absence of atrial fibrillation (P=0.01), TAVI (P=0.007), and larger increase in aortic valve area after the procedure (P=0.01) were independently associated with better recovery of LVEF.</AbstractText>In patients with severe aortic stenosis and depressed LV systolic function, TAVI is associated with better LVEF recovery compared with SAVR. TAVI may provide an interesting alternative to SAVR in patients with depressed LV systolic function considered at high surgical risk.</AbstractText> |
5,150 | Ventricular fibrillation with diminished internal mammary artery graft flow during sternal retraction. | Ventricular fibrillation is a common arrhythmia encountered after the termination of cardiopulmonary bypass. Risk is augmented in patients who are undergoing repeat cardiac procedures with most documented complications occurring during repeat sternotomy. Aortic valve surgery is more complex after coronary artery bypass grafting using internal mammary arteries, and it compounds the increased risk of repeat sternotomy. This case report describes a low-flow state artificially created by sternal retraction applying tension on a right internal mammary artery to posterior descending artery anastomosis, with resultant unrecognized myocardial ischemia yielding refractory ventricular fibrillation during aortic valve replacement. |
5,151 | Pulseless electrical activity in cardiac arrest: electrocardiographic presentations and management considerations based on the electrocardiogram. | Pulseless electrical activity (PEA), a cardiac arrest rhythm scenario with an associated poor prognosis, is defined as cardiac electrical activity without a palpable pulse. Considering both outpatient and inpatient cardiac arrest presentations, PEA as a rhythm group has been increasing over the past 10 to 20 years with a corresponding decrease in the "shockable" rhythms, such as pulseless ventricular tachycardia and ventricular fibrillation. This review focuses on electrocardiographic findings encountered in PEA cardiac arrest presentations with an emphasis on recognition of patients with a potential opportunity for successful resuscitation. |
5,152 | A dangerous fruit juice. | We report the case of a female patient presenting to the emergency department with postprandial syncope and atrial fibrillation. After amiodarone administration, the electrocardiogram showed marked QT prolongation associated with ventricular arrhythmias, including an episode of torsade de pointes requiring immediate electrical cardioversion. During history taking, the patient reported that she had been drinking large amounts of grapefruit juice regularly. The inhibition of amiodarone metabolism induced by grapefruit juice was responsible for enhancing the proarrhythmic effects of the drug with development of electrical storm. |
5,153 | Termination of sustained atrial flutter and fibrillation using low-voltage multiple-shock therapy. | Defibrillation therapy for atrial fibrillation (AF) and flutter (AFl) is limited by pain induced by high-energy shocks. Thus, lowering the defibrillation energy for AFl/AF is desirable.</AbstractText>In this study we applied low-voltage multiple-shock defibrillation therapy in a rabbit model of atrial tachyarrhythmias comparing its efficacy to single shocks and antitachycardia pacing (ATP).</AbstractText>Optical mapping was performed in Langendorff-perfused rabbit hearts (n = 18). Acetylcholine (7 ± 5 to 17 ± 16 μM) was administered to promote sustained AFl and AF, respectively. Single and multiple monophasic shocks were applied within 1 or 2 cycle lengths (CLs) of the arrhythmia.</AbstractText>We observed AFl (CL = 83 ± 15 ms, n = 17) and AF (CL = 50 ± 8 ms, n = 11). ATP had a success rate of 66.7% in the case of AFl, but no success with AF (n = 9). Low-voltage multiple shocks had 100% success for both arrhythmias. Multiple low-voltage shocks terminated AFl at 0.86 ± 0.73 V/cm (within 1 CL) and 0.28 ± 0.13 V/cm (within 2 CLs), as compared with single shocks at 2.12 ± 1.31 V/cm (P < .001) and AF at 3.46 ± 3 V/cm (within 1 CL), as compared with single shocks at 6.83 ± 3.12 V/cm (P =.06). No ventricular arrhythmias were induced. Optical mapping revealed that termination of AFl was achieved by a properly timed, local shock-induced wave that collides with the arrhythmia wavefront, whereas AF required the majority of atrial tissue to be excited and reset for termination.</AbstractText>Low-voltage multiple-shock therapy terminates AFl and AF with different mechanisms and thresholds based on spatiotemporal characteristics of the arrhythmias.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,154 | Immediate and 6-month outcomes of transapical and transfemoral Edwards-Sapien prosthesis implantation in patients with aortic stenosis. | severe symptomatic aortic valve stenosis is an unequivocal indication for surgical valve replacement, assuring symptoms relief and increasing survival. About one third of elderly patients is not being operated due to, among others, high peri-procedural risk and comorbidities. Transcatheter aortic valve implantation (TAVI) has recently become a valuable therapeutic option for these patients.</AbstractText>to present early results of first TAVI Edwards-Sapien procedures in our hospital, performed in symptomatic patients with high operational risk or other contraindications for conventional surgery, as well as the results of 6-month follow-up.</AbstractText>twelve patients referred for TAVI were included in the analysis. The valve was implanted in 11 patients and in 1 patient the procedure was finished with aortic valve valvuloplasty. Eight (72.7%) patients underwent transapical (TA) and 3 (27.3%) patients transfemoral (TF) TAVI. Seven (63.6%) 26 mm valves and 4 (34.4%) 23 mm valves were implanted.</AbstractText>the efficacy of the procedure was 92%: 100% in the TA group, and 75% in the TF group. During the procedure 1 patient developed ventricular fibrillation. Atrial fibrillation and right ventricle perforation by the endocavitary electrode was observed in another patient. Prolonged wound healing occurred in 4 patients and contrast-induced renal failure occurred in 2 patients. There were no deaths at 30-days. Two patients had a pacemaker implanted during hospitalisation. A significant improvement of echocardiographic parameters was observed: maximum gradient across the aortic valve was 104.4 ± 23.9 mm Hg before vs 25.2 ± 6.1 mm Hg after the intervention, p = 0.000001, mean gradient - 63.8 ± 18.3 vs 12.7 ± 3.7 mm Hg, p = 0.000004, and valvular surface - 0.7 ± 0.2 vs 1.5 ± 0.2 cm2, p = 0.000106, respectively. During the 6-month follow-up period 1 patient died of multiorgan failure and 6 patients required another hospitalisation. After 6 months an improvement in physical capacity was observed in all but one patients (NYHA II - 9 patients, NYHA III - 1 patient).</AbstractText>1. The authors' initial experiences with TAVI Edwards-Sapien procedure confirm its efficacy and safety in patients with symptomatic aortic stenosis and high surgical risk. 2. Echocardiographic parameters of the implanted valves, assessed during hospitalisation and 6 month later, are satisfactory. 3. Due to the risk of complications, patients require careful observation in the postoperative period and during short-term follow-up.</AbstractText> |
5,155 | Predicting atrial fibrillation recurrence with circulating inflammatory markers in patients in sinus rhythm at high risk for atrial fibrillation: data from the GISSI atrial fibrillation trial. | Inflammation may play a significant role in the pathogenesis of atrial fibrillation (AF).</AbstractText>To examine the roles of three systemic inflammatory markers in predicting recurrent AF.</AbstractText>The association between the plasma concentrations of high-sensitivity C reactive protein (hsCRP), interleukin-6 (IL-6) and pentraxin-3 (PTX3) with echocardiographic parameters and with the time to first recurrence of AF was tested in 382 patients with a history of AF but in sinus rhythm at randomisation, enrolled in the GISSI-AF biohumoral study.</AbstractText>Baseline PTX3 was related to left atrial, but not to left ventricular chamber volume. During one year of follow-up, 204 patients (53.1%) had a recurrent AF. There were no significant differences in baseline median [Q1-Q3] plasma concentrations of IL-6, hsCRP and PTX3 among patients with (2.11 [1.47-3.74] pg/ml, 3.30 [1.40-6.80] mg/l and 4.66 [3.27-6.97] ng/ml, respectively) or without recurrent AF (2.09 [1.37-2.90] pg/ml, p=0.182; 3.00 [1.10-6.20] mg/l, p=0.333; 5.09 [3.22-7.98] ng/ml, p=0.637). At 6 and 12 months follow-up, AF patients had significantly higher concentrations of IL-6 and PTX3 than those in sinus rhythm, and those with most recent episodes of AF had higher hsCRP. Baseline levels of IL-6, hsCRP or PTX3 were not significantly associated with a higher risk of recurrence of AF.</AbstractText>In patients with a history of AF, but without significant left ventricular dysfunction or heart failure, inflammatory biomarkers may be raised but are, at best, weak predictors of the risk for first recurrence of AF.</AbstractText> |
5,156 | [Transient apical dysfunction syndrome (Tako-Tsubo) simulating acute myocardial infarction]. | Transient apical dysfunction syndrome (TADS) is frequently misdiagnosed as an acute coronary syndrome (ACS). It is characterized by electrocardiographic alterations and elevated myocardial necrosis markers, accompanied by hypokinesia, akinesia or anteroapical dyskinesia, in absence of significant coronary disorders. It generally resolves in days or weeks with individualized support measures. We present the case of a female patient referred to our service for a myocardial perfusion imaging study due to a history suggestive of an acute coronary syndrome after a stressful event. |
5,157 | Atrial Tachycardias Occurring After Atrial Fibrillation Ablation: Strategies for Mapping and Ablation. | The occurrence of left atrial tachycardias (AT) after catheter ablation for atrial fibrillation (AF) is common, especially after more extensive ablation of persistent AF. These AT are invariably symptomatic and often do not respond to medical therapy. The initial strategy involves ventricular rate control, cardioversion, and observation as some tachycardias may resolve with time. For persistent ATs, effective management frequently requires catheter intervention. Careful characterization of the tachycardia mechanism is essential in designing an effective ablation strategy that would also avoid further creation of pro-arrhythmic substrate. With this review, we summarize the incidence, mechanism, diagnosis and treatment of ATs occurring after AF ablation. |
5,158 | Rapid ventricular pacing: a fast, reliable, and safe technique for optimization of image acquisition during rotational angiography for catheter ablation of atrial fibrillation. | Rotational angiography is a novel method for three-dimensional reconstruction of the left atrium and pulmonary veins during catheter ablation for atrial fibrillation, but is still hampered by suboptimal reconstructions in a considerable number of patients. We describe the results of rapid pacing of the right ventricle for optimization of image acquisition during rotational angiography. |
5,159 | Is this a philosophic issue? Do patients with drug-induced Brugada type ECG have poor prognosis? (Pro). | Brugada syndrome (BS) has an intermittent or concealed type, which can be unmasked by the sodium (Na(+))-channel-blocker challenge test. The appropriate risk stratification of patients with a drug-induced Brugada-type electrocardiographic (ECG), especially those without a history of syncope or aborted sudden cardiac death, remains unclear. The prognosis of patients with BS depends on the clinical type, cardiac arrest, syncope or if asymptomatic. The ratio of the asymptomatic group varies from 56.9% to 63.6% and, furthermore, their annual cardiac event rate is relatively lower at 0.24-3.6% compared with the cardiac arrest group. Patients with a drug-induced Brugada-type ECG have a poor prognosis if they had a history of ventricular fibrillation (VF) or aborted sudden cardiac death, because their risk becomes similar to that of patients with spontaneous Brugada-type ECG. They have the disturbance of the Na(+)-channel and the electrophysiologic substrate of VF, proven by the high inducibility of VF by stimulation test even in patients without spontaneous VF. Spontaneous VF will never occur if there is no VF substrate. Implantable cardioverter-defibrillators will certainly protect them, so patients with a drug-induced Brugada-type ECG, even without a history of VF or aborted sudden cardiac death, should be considered to have a poor prognosis. |
5,160 | Low risk for arrhythmic events in asymptomatic patients with drug-induced type 1 ECG. Do patients with drug-induced Brugada type ECG have poor prognosis? (Con). | The type 1 ST-segment elevation is diagnostic for Brugada syndrome (BS) and its presence may sometimes be associated with a high risk of arrhythmic events. The type 1 ECG is also known to be unmasked by administration of sodium-channel blockers in equivocal or suspected cases of BS, and the drug-challenge test is frequently used in the diagnostic approach. In large cohort studies the spontaneous appearance of the type 1 ECG with symptoms of aborted sudden death or unexplained syncope are indicative of a poor prognosis for patients with BS compared with not having clinical symptoms. Therefore, the spontaneous type 1 ECG appears to represent an important predictive sign for cardiac events. It is unknown, however, whether or not the drug-induced type 1 ECG is as useful as the spontaneous type 1 for predicting cardiac events in asymptomatic subjects showing non-type 1 ECG. Review of the literature for large cohort studies indicates that there is a low incidence of arrhythmic events in asymptomatic patients with either the spontaneous or drug-induced type 1 ECG compared with symptomatic subjects, and the drug-induced type 1 ECG in asymptomatic patients does not add to an increase in arrhythmic risk. Therefore, drug testing to unmask the type 1 ECG in asymptomatic patients with a non-type 1 BS ECG does not have an additional value for risk stratification of cardiac events, although it might be useful in symptomatic patients showing only the non-type 1 ECG. |
5,161 | The role of pulmonary veins vs. autonomic ganglia in different experimental substrates of canine atrial fibrillation. | Pulmonary vein (PV)-encircling ablation, which is effective in suppressing atrial fibrillation (AF), damages autonomic ganglia near the PV ostia. This study examined the effects of PV isolation (PVI) vs. peri-PV ganglionic plexus ablation (GPA) in two discrete canine AF models: ventricular tachypacing (240 bpm, 2 weeks)-induced congestive heart failure (CHF), and atrial tachypacing (400 bpm, 1 week)-induced atrial tachycardia remodeling (ATR).</AbstractText>All PVs were isolated with an epicardial radiofrequency clamp in nine CHF and eight ATR dogs. Peri-PV ganglionic plexi (identified by bradycardic responses to high-frequency stimulation) were ablated in six CHF and five ATR dogs with an epicardial radiofrequency-ablation pen. Electrophysiologic measurements, including 240-electrode AF mapping, were obtained and dominant frequencies (DFs) determined. Atrial growth associated protein-43 (GAP-43) and neurofilament-M (NF-M) expression were determined immunohistologically. In CHF, neither PVI nor GPA affected AF duration, DF or the already low AF vulnerability. In ATR, PVI reduced AF vulnerability (75 ± 6% to 55 ± 11%, P< 0.05) but did not alter AF duration or DF. In contrast, GPA prolonged atrial refractory period and decreased AF vulnerability (75 ± 8 to 30 ± 10%, P< 0.05), AF duration (617 ± 246 to 39 ± 23 s, **P< 0.01), and DF (11.4 ± 0.6 to 8.6 ± 0.3** Hz, left atrium) in ATR dogs. Both GAP-43 and NF-M expression were decreased in CHF (by 63.1** and 60.0%**) and increased in ATR (by 65.5** and 92.1%, P< 0.001) compared with control.</AbstractText>PVs play a minor role in experimental AF due to CHF or ATR, but autonomic ganglia are important in AF related to ATR. Differential neural remodelling may contribute to varying effects of GPA in discrete AF substrates.</AbstractText> |
5,162 | Modification of a hybrid technique for closure of muscular ventricular septal defects in a pig model. | Closure of muscular ventricular septal defects (mVSDs) beyond the moderator band is still a challenge for both surgeons and interventional cardiologists. We evaluated a new technique in a pig model for hybrid patch closure of mVSDs via 2 stab wound incisions in the left ventricle (LV) without cardiopulmonary bypass.</AbstractText>Ten pigs underwent left anterolateral thoracotomy to expose the LV. mVSDs were created via a stab wound incision of the lateral wall of the LV under epicardial echocardiographic control. The patch system was forwarded through a second puncture of the LV apex and positioned in front of the mVSD. The stapler for fixation of the patch was introduced through the same incision as used for VSD creation. Finally, the patch was attached to the septum with nitinol anchors under epicardial echocardiographic and fluoroscopic guidance. Finally, detailed echocardiographic evaluation was done. All hearts were explanted, and macroscopic evaluation was done, either immediately after patch implantation (n = 4) or after 90 days (n = 6).</AbstractText>mVSD creation was successful in all pigs. Closure of mVSDs was successful in 8 of 10 pigs, as confirmed by echocardiography, hemodynamic measurements, and macroscopic examination. One patch embolized through the mVSD into the pulmonary artery because of insecure fixation, and 1 animal died during the procedure because of ventricular fibrillation. The final echocardiographic evaluation revealed good LV function and no damage to the valves.</AbstractText>Closure of mVSDs can be successfully performed in a hybrid technique on the beating heart with 2 stab wound incisions; however, further modifications need to be developed before clinical application.</AbstractText> |
5,163 | [An autopsy case of senile dementia suspected to be influenced by cerebral amyloid angiopathy with multiple cortical microinfarcts]. | A Japanese male showed gradually progressing dementia with psychiatric symptoms including abnormal behavior, night and day reversal, nocturnal delirium, loud shouting, agitation, resistance to care, and loud soliloquy. The patient had a history of right cerebral embolism due to atrial fibrillation 1 month before the onset of dementia. Head CT revealed widespread cerebral infarction in the right cerebral hemisphere with bilateral lateral ventricular dilatation. The patient died at the age of 83, 10 months after the onset of cerebral embolism. The clinical diagnosis was mixed-type dementia. On autopsy the brain weighed 1,160 g. Widespread cerebral amyloid angiopathy (CAA) was observed, with distribution most severe in the cerebral cortical vessels and slightly milder in the leptomeningial and subarachnoid vessels. The artery, arteriole, and capillary walls were thickened by the deposition of amorphous, eosinophilic and beta-protein immunopositive amyloid. Abeta-deposition was more severe in capillaries and CAA tended to be more severe in the occipital regions. Multiple cortical microinfarcts were found, particularly in the crests of the cerebral gyri of watershed zones. Cerebral white matter, basal ganglia, thalamus, brainstem and spinal cord were relatively preserved from CAA. Infarction was not apparent, except for an embolic lesion in the right cerebral hemisphere and the cortical microinfarcts. We did not observe fibrinoid necrosis, granulomatous angiitis or giant cell reaction associated with CAA-vasculopathies. Rare instances were observed of neurofibrillary tangles and senile plaques corresponding to Braak stages II and A, respectively. We thought the multiple cortical microinfarcts occurred due to chronic hypoperfusion associated with CAA-associated vasculopathies of capillaries in the cerebral cortex. We suspected that the dementia was influenced by the CAA with multiple cortical microinfarcts. Pathologic findings of the patient suggest that CAA without AD-related Abeta-deposition might exist and that capillary Abeta-deposition might be an important factor of hemodynamic perturbation. |
5,164 | [Successful use of intravenous amiodarone for refractory ventricular fibrillation just after releasing aortic cross-clamp]. | Amiodarone is widely used in Europe and the United States for refractory ventricular fibrillation (VF) in various situations, such as VF after myocardial infarction or out-of-hospital cardiac arrest. We report a case of successful treatment with amiodarone of refractory VF immediately after releasing aortic cross-clamp in cardiac surgery. A 66-year-old man suffering from severe aortic stenosis underwent aortic valve replacement (AVR). General anesthesia was induced with propofol and remifentanil, and subsequently AVR was performed under cardiopulmonary bypass. Just after releasing aortic cross-clamp, VF occurred, and it continued despite multiple trials of cardioversion with direct current (DC) shocks of 20 J or 30 J. Furthermore, some DC shocks of 30 J or 50 J after administering lidocaine 60 mg and 0.5 mol x l(-1) magnesium sulfate 20 ml were also ineffective. Then, nifekalant 20 mg was administered and DC shocks of 50 J were repeated intermittently, but VF still persisted. Eventually, VF disappeared after a final DC shock of 50 J with intravenous amiodarone 125 mg. Overall duration of VF was 60 minutes. The patient's trachea was extubated three days after the surgery without any complications. Intravenous amiodarone may be one of the most useful remedies for some types of arrhythmias including persistent VE. |
5,165 | Atrioventricular reverse remodeling after valve repair for chronic severe mitral regurgitation: 1-year follow-up. | Chronic severe mitral regurgitation is associated with poor clinical outcome because chronic volume overload leads to hemodynamic changes and left ventricular and left atrial remodeling. Few data are available regarding left atrial volume index regression (LAVIR) and left ventricular mass index regression (LVMIR) after valve surgery for mitral regurgitation. We aimed to identify predictive correlates of LAVIR and LVMIR and to assess the relationship between these regressions.</AbstractText>Volume overload in chronic severe mitral regurgitation may influence left atrial and ventricular remodeling and reverse remodeling.</AbstractText>Eighty-five patients who underwent valve repair for severe chronic mitral regurgitation were consecutively enrolled. Plasma N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) and echocardiographic measurements were performed before surgery, before discharge, and at 12 months after surgery. LAVIR and LVMIR were assessed using serial echocardiography.</AbstractText>There were significant decreases in left ventricular mass index (LVMI; from 125.9 ± 31.3 g/m² to 94.8 ± 28.6 g/m², P = 0.001) and left atrial volume index (LAVI; from 75.3 ± 33.5 mL/m² to 41.7 ± 16.0 mL/m², P = 0.001) after surgery. Preoperative LAVI positively correlated with preoperative LVMI (r = 0.437, P = 0.001) and LAVIR positively correlated with LVMIR (r = 0.347, P = 0.001). In multivariate stepwise linear regression analysis, preoperative LAVI, age, hypertension, and atrial fibrillation were independently predictive of LAVIR, and preoperative LVMI, hypertension, and NT-proBNP were independently predictive of LVMIR.</AbstractText>Volume overload in chronic severe mitral regurgitation may influence left ventricular remodeling and reverse remodeling, as well as left atrial remodeling and reverse remodeling. Preoperative lower LAVI, younger age, absence of hypertension, and absence of atrial fibrillation may predict LAVIR, and preoperative lower LVMI, lower NT-proBNP levels, and absence of hypertension may predict LVMIR after surgery for chronic severe mitral regurgitation.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,166 | Outcome of invasive electrophysiological procedures and gender: are males and females the same? | The aim of this review is to summarize the available evidence on gender-related differences in outcome of invasive electrophysiological procedures. Gender exerts significant influences on the epidemiology, pathophysiology, and clinical presentation of many cardiac rhythm disorders. Women with supraventricular arrhythmias have a higher incidence of atrioventricular nodal reentrant tachycardia, a lower prevalence of atrioventricular accessory pathways, and increased arrhythmia inducibility during luteal phases of the menstrual cycle. Catheter ablation of supraventricular arrhythmias appears equally effective in the 2 genders, although women present to catheter ablation later, with more symptoms, and after having failed more antiarrhythmic drugs. The outcome of catheter ablation of atrial fibrillation in women has been reported worse than in men, which may be explained by a later referral. Accordingly, women present to catheter ablation with a higher incidence of long-standing persistent atrial fibrillation. Of note, the outcome of catheter ablation of atrial flutter does not seem to differ between genders. To date, with regard to ventricular arrhythmias, no gender-related differences in outcome of catheter ablation procedures have been reported. However, pathophysiology and risk factors underlying ventricular arrhythmias appear different in the two genders. Severe left ventricular dysfunction does not perform equally as a predictor for sudden cardiac death in women as compared to men, and the survival benefit of prophylactic implantable cardioverter-defibrillator (ICD) implantation in women is inconclusive. On the other hand, the clinical outcome after cardiac resynchronization therapy seems to be more favorable in women, who experience a greater degree of reverse left ventricular remodeling. |
5,167 | Combining shock reduction strategies to enhance ICD therapy: a role for computer modeling. | To develop a computer model to test shock reduction strategies such as antitachycardia pacing and shock withholding for supraventricular rhythms, oversensing, and nonsustained ventricular tachycardia.</AbstractText>While the implantable cardioverter defibrillator (ICD) can reduce mortality, inappropriate ICD shocks remain a limitation. Randomized trials provide evidence of efficacy, but they are not always practical. Computer models provide an alternative approach, and are particularly useful when evaluating multiple interventions.</AbstractText>A computer model was developed using clinical data and validated in a large ICD data set (EMPIRIC). After validation, the model was applied to 736 adjudicated clinical episodes from the ICD arm of Sudden Cardiac Death Heart Failure Trial (SCD-HeFT).</AbstractText>The shock reduction strategies hypothetically reduced the number of VT/VF shocked episodes in SCD-HeFT by an estimated 59% (from 952 observed to 395 modeled shocks, probability of >0.999) at detection duration settings (18 of 24 intervals). The percentage of patients experiencing inappropriate shocks over 5 years was decreased by 15% (23.5-8.4%), and the number of shocks for non-VT/VF episodes was decreased from 423 to 77 (82% reduction). The percentage of patients receiving shocks for VT/VF was reduced from 30.7% (SCD-HeFT) to 26.1% with the addition of ATP. Extended detection (24 of 32 or 30 of 40 intervals) showed modest additional improvement compared to 18 of 24 intervals.</AbstractText>Computer modeling is able to predict the results of a known clinical trial and demonstrate that shock reduction strategies have the potential to significantly reduce inappropriate and unnecessary ICD shocks versus the mandated programming used in SCD-HeFT.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,168 | A case of atrial fibrillation induced by inhaled fluticasone propionate. | Atrial fibrillation (AF) is the most common rhythm disorder observed in clinical practice. Several case reports and case-control studies have associated this condition with the use of systemic corticosteroids. However, to our knowledge, no case of AF induced by inhaled corticosteroids has been reported in the literature. We describe here the case of a 15-year-old boy who reported a paroxysmal AF with fast ventricular response after the administration of fluticasone propionate, which resolved after discontinuation of the drug. Use of the Naranjo adverse-drug-reaction probability scale indicated a possible relationship between the patient's development of AF and fluticasone propionate therapy. More studies are needed to confirm the association between this arrhythmia and the use of high doses of inhaled corticosteroids. Data from this report already suggest that clinicians should be aware of the possibility of adverse cardiovascular reactions when corticosteroids are prescribed also as inhaled preparations. |
5,169 | Effects of therapeutic hypothermia on coagulopathy and microcirculation after cardiopulmonary resuscitation in rabbits. | The aim of this study was to investigate the effects of therapeutic hypothermia (TH) on coagulopathy and cerebral microcirculation disorder after cardiopulmonary resuscitation (CPR) in rabbits.</AbstractText>Cardiac ventricular fibrillation was induced by alternating current in 24 New Zealand rabbits, and hypothermia was induced by surface cooling or normothermia (NT) was maintained for 12 hours after the return of spontaneous circulation (ROSC). Several physiologic indexes were measured before CPR and at 4, 8, and 12 hours after ROSC. The microcirculation flow in the cerebral cortex was measured with a PERIMED Multichannel Laser Doppler system (Perimid, Sweden), and glomerular fibrin deposition was determined by microscopy.</AbstractText>Compared with the NT group, the prothrombin time, activated partial thromboplastin time, and international normalized ratio in the TH group were increased; there were no differences in anti-thrombin-III, protein C, and d-dimer indexes. The microcirculation flow in the cerebral cortex before CPR and after ROSC at 4, 8, and 12 hours was 401.60 ± 11.76, 258.86 ± 34.58, 317.59 ± 23.36, and 371.98 ± 5.79 mL/min, respectively, in the NT group, and 398.18 ± 12.91, 336.19 ± 19.27, 347.76 ± 13.80, and 383.78 ± 3.29 mL/min, respectively, in the TH group. There were apparent disparities at each checkpoint after ROSC in these 2 groups (4 hours: P = .001; 8 hours: P = .011; 12 hours: P = .009). The Pearson correlation test showed that the microcirculation flow in the cerebral cortex was positively correlated with activated partial thromboplastin time after ROSC (4 hours: r = 0.503, P = .033; 8 hours: r = 0.565, P = .035; 12 hours: r = 0.774, P = .009), but not with other coagulation parameters.</AbstractText>Therapeutic hypothermia might cause coagulant dysfunction but concomitantly improves the microcirculation flow in the cerebral cortex, which might be an effect of TH that results in cerebral protection.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,170 | A KCR1 variant implicated in susceptibility to the long QT syndrome. | The acquired long QT syndrome (aLQTS) is frequently associated with extrinsic and intrinsic risk factors including therapeutic agents that inadvertently inhibit the KCNH2 K(+) channel that underlies the repolarizing I(Kr) current in the heart. Previous reports demonstrated that K(+) channel regulator 1 (KCR1) diminishes KCNH2 drug sensitivity and may protect susceptible patients from developing aLQTS. Here, we describe a novel variant of KCR1 (E33D) isolated from a patient with ventricular fibrillation and significant QT prolongation. We recorded the KCNH2 current (I(KCNH2)) from CHO-K1 cells transfected with KCNH2 plus wild type (WT) or mutant KCR1 cDNA, using whole cell patch-clamp techniques and assessed the development of I(KCNH2) inhibition in response to well-characterized KCNH2 inhibitors. Unlike KCR1 WT, the E33D variant did not protect KCNH2 from the effects of class I antiarrhythmic drugs such as quinidine or class III antiarrhythmic drugs including dofetilide and sotalol. The remaining current of the KCNH2 WT+KCR1 E33D channel after 100 pulses in the presence of each drug was similar to that of KCNH2 alone. Simulated conditions of hypokalemia (1mM [K(+)](o)) produced no significant difference in the fraction of the current that was protected from dofetilide inhibition with KCR1 WT or E33D. The previously described α-glucosyltransferase activity of KCR1 was found to be compromised in KCR1 E33D in a yeast expression system. Our findings suggest that KCR1 genetic variations that diminish the ability of KCR1 to protect KCNH2 from inhibition by commonly used therapeutic agents constitute a risk factor for the aLQTS. |
5,171 | Antiarrhythmic and antioxidant activity of novel pyrrolidin-2-one derivatives with adrenolytic properties. | A series of novel pyrrolidin-2-one derivatives (17 compounds) with adrenolytic properties was evaluated for antiarrhythmic, electrocardiographic and antioxidant activity. Some of them displayed antiarrhythmic activity in barium chloride-induced arrhythmia and in the rat coronary artery ligation-reperfusion model, and slightly decreased the heart rate, prolonged P-Q, Q-T intervals and QRS complex. Among them, compound EP-40 (1-[2-hydroxy-3-[4-[(2-hydroxyphenyl)piperazin-1-yl]propyl]pyrrolidin-2-one showed excellent antiarrhythmic activity. This compound had significantly antioxidant effect, too. The present results suggest that the antiarrhythmic effect of compound EP-40 is related to their adrenolytic and antioxidant properties. A biological activity prediction using the PASS software shows that compound EP-35 and EP-40 can be characterized by antiischemic activity; whereas, compound EP-68, EP-70, EP-71 could be good tachycardia agents. |
5,172 | A major role for HERG in determining frequency of reentry in neonatal rat ventricular myocyte monolayer. | the rapid delayed rectifier potassium current, I(Kr), which flows through the human ether-a-go-go-related (hERG) channel, is a major determinant of the shape and duration of the human cardiac action potential (APD). However, it is unknown whether the time dependency of I(Kr) enables it to control APD, conduction velocity (CV), and wavelength (WL) at the exceedingly high activation frequencies that are relevant to cardiac reentry and fibrillation.</AbstractText>to test the hypothesis that upregulation of hERG increases functional reentry frequency and contributes to its stability.</AbstractText>using optical mapping, we investigated the effects of I(Kr) upregulation on reentry frequency, APD, CV, and WL in neonatal rat ventricular myocyte (NRVM) monolayers infected with GFP (control), hERG (I(Kr)), or dominant negative mutant hERG G628S. Reentry frequency was higher in the I(Kr)-infected monolayers (21.12 ± 0.8 Hz; n=43 versus 9.21 ± 0.58 Hz; n=16; P<0.001) but slightly reduced in G628S-infected monolayers. APD(80) in the I(Kr)-infected monolayers was shorter (>50%) than control during pacing at 1 to 5 Hz. CV was similar in both groups at low frequency pacing. In contrast, during high-frequency reentry, the CV measured at varying distances from the center of rotation was significantly faster in I(Kr)-infected monolayers than controls. Simulations using a modified NRVM model predicted that rotor acceleration was attributable, in part, to a transient hyperpolarization immediately following the AP. The transient hyperpolarization was confirmed experimentally.</AbstractText>hERG overexpression dramatically accelerates reentry frequency in NRVM monolayers. Both APD and WL shortening, together with transient hyperpolarization, underlies the increased rotor frequency and stability.</AbstractText> |
5,173 | Catheter ablation of electrical storm in patients with structural heart disease. | Electrical storm (ES) adversely affects prognosis of patients and may become a life-threatening event. Catheter ablation (CA) has been proposed for the treatment of ES. Our goal was to evaluate the efficacy of CA ablation both in acute and long-term suppression of ES.</AbstractText>Fifty consecutive patients with coronary artery disease (38), idiopathic dilated cardiomyopathy (5), arrhythmogenic right ventricular cardiomyopathy (6), and/or with combined aetiology (1) underwent CA for ES. Mean left ventricular ejection fraction (LVEF) was 29 ± 11%. All patients underwent electroanatomical mapping, and CA was performed to abolish all inducible ventricular arrhythmias. The ES was suppressed by CA in 84% of patients. During the follow-up of 18 ± 16 months, 24 patients had no recurrences of any ventricular tachycardia (VT; 48%). Repeated procedure was necessary to suppress the recurrent ES in 13 cases (26%). Statistical analysis revealed that low LVEF (22 ± 3 vs. 31 ± 12%; P < 0.001), increased LVend-diastolic diameter (72 ± 9.1 vs. 64 ± 8.9 mm; P = 0.0135), and renal insufficiency (P < 0.001) were the univariate predictors of early mortality or necessity for heart transplantation. Recurrence of ES despite previous CA procedure was associated with a higher risk of death or heart transplant during follow-up (P < 0.05).</AbstractText>Catheter ablation is effective in acute suppression of ES and often represents a life-saving therapy. In the long term, it prevents recurrences of any VT in about half of the treated patients.</AbstractText> |
5,174 | New conventional long-term survival normovolemic cardiac arrest pig model. | A reproducible long-term intensive care and outcome cardiac arrest model for exploring new cerebral preservation strategies is needed. We tried to determine effects and limitations of current therapies after different 'no-flow' times.</AbstractText>Thirty-five female Large White Breed pigs (26-37kg) were included in the study. Three pigs served as sham animals without cardiac arrest (CA). Ventricular fibrillation (VF) CA was induced in 32 animals for 0, 7, 10 and 13min (each group consisting of 8 animals), followed by 8min of chest compressions, mechanical ventilation and vasopressors. Thereafter, up to 3 defibrillations were delivered. After restoration of spontaneous circulation (ROSC), the animals underwent intensive care for 20h. Neurologic examination was performed at designated time points using a neurologic deficit (ND) and an overall performance category (OPC) score.</AbstractText>Restoration of spontaneous circulation was achieved in 8 of 8 animals in the 0min-group, 6 of 8 in the 7min-group, 7 of 8 in the 10min-group and 0 of 8 in the 13min-group. All animals of the sham-group and 0min-group were neurologically intact survivors; the 7 and 10min-groups showed a median ND of 55%(26;94) and 73%(58;78), respectively. There were no significant differences between the 7 and 10min-groups regarding OPC and NDS. Coronary perfusion pressure during CPR decreased concordantly with 'no-flow' times with a tendency towards significance.</AbstractText>This study established a reproducible cardiac arrest and resuscitation model in pigs which will be used to test novel resuscitation strategies to improve neurologic outcome after cardiac arrest.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,175 | Systemic fibrinolysis through intraosseous vascular access in ST-segment elevation myocardial infarction. | In emergency situations, intraosseous cannulation represents an alternative route of vascular access when peripheral vein insertion is difficult. We present the first documented case of intraosseous systemic fibrinolysis in a patient with ST-segment elevation myocardial infarction. In this case, repetitive episodes of ventricular fibrillation occurred soon after first contact with emergency care providers. Given that the patient had difficult peripheral venous access, an intraosseous catheter was inserted. Fibrinolytics and antiarrhythmic drugs were administered though this line, resulting in resolution of coronary ischemia and electrical instability, without complications. Intraosseous cannulation represents a novel route for administration of systemic fibrinolysis in cases of difficult peripheral venous access in the out-of-hospital setting. |
5,176 | Clinical impact of screening for sleep related breathing disorders in atrial fibrillation. | The aim of this study was to quantify daytime symptoms in atrial fibrillation (AF) patients with and without sleep related breathing disorders (SRBD).</AbstractText>SRBD are common in patients with AF but little is known about daytime symptoms among those with SRBD.</AbstractText>Patients with AF admitted to clinics of two tertiary referral hospitals for a variety of different cardiovascular diseases were screened with a trans-nasal airflow measurement device allowing measurement of the apnea-hypopnea-index. Data on cardiac risk factors, left ventricular ejection fraction (LVEF) and cardiac medication were collected. Presence of SRBD was defined as an AHI ≥ 15/h. The Epworth sleepiness scale (ESS) was used to quantify daytime symptoms.</AbstractText>Of 102 screened patients 8 were excluded due to device malfunction (n=1), dislocation of nasal cannula (n=6), or hyperthyroidism (n=1). Among the remaining 94 patients, 40 (43%) were diagnosed with SRBD. Patients with and without SRBD had similar age, body mass index, LVEF and cardiac medication. The prevalence of coronary artery disease was higher in patients with SRBD than in those without (50 vs. 17%; p=0.0007). ESS score was low and similar in both groups (no SRBD: median 4, interquartile range (IQR) 2-4 vs. SRBD: 5, IQR 3-8; p=0.14). Only 6/40 (5%) of the patients underwent overnight polysomnography and 2 (5%) started CPAP ventilation during follow-up.</AbstractText>Even though SRBD are common in patients with AF, the prevalence of daytime symptoms is rare. Consequently, most patients will not initiate CPAP ventilation after positive SRBD screening.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,177 | Clinical and electrophysiological profile of Brugada syndrome in the Tunisian population. | Most clinical studies of the clinical profile of Brugada syndrome (BS) have been conducted in either Asia, Europe, or America and their applicability to North African populations is largely unknown. The aim of the study was to analyze the clinical profile of BS in Tunisian patients.</AbstractText>The clinical and follow-up data of 24 patients (22 men, mean age: 40.8 ± 13.7 years) were collected since 2002. Baseline characteristics, morbidity, and mortality data were obtained from medical records.</AbstractText>One patient (4.16%) survived sudden cardiac death (SCD), four patients (16.3%) had syncope, and 19 patients (79.1%) were asymptomatic. Eleven patients (45.8%) had a family history of SCD. Twenty patients showed a spontaneous coved-type ST-segment elevation on electrocardiogram and after medical challenge on the four remnants. An electrophysiological study was performed in 15 of 24 patients (62.5%), during which ventricular fibrillation was induced in six patients (40%); three of the six patients were previously asymptomatic. An implantable cardioverter defibrillator (ICD) was implanted in 14 patients (58.3%). After a mean follow-up of 26 ± 21 months, one patient died from a noncardiac cause and one patient (with a history of aborted SCD) received an appropriate shock from his ICD. None of the asymptomatic and noninducible patients experienced a cardiac event.</AbstractText>BS is present in the North African population and is probably under-recognized. Tunisian patients with BS share with their western and Asiatic counterparts similar clinical profile.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,178 | Failure of transvenous ICD to terminate ventricular fibrillation in a patient with left ventricular noncompaction and polycystic kidneys. | Implantable cardioverter defibrillator (ICD) testing in patients with left ventricular noncompaction (LVNC) at the time of implantation and potential difficulties with ventricular fibrillation (VF) induction/termination in LVNC patients are often not stated in the literature. This report describes the failure of transvenous implantation of an ICD in a 40-year-old patient with LVNC and polycystic kidneys. A high defibrillation threshold (DFT) prevented termination of ICD-induced VF. This case suggests that DFT testing should be considered in any LVNC patient during ICD implantation. The association of LVNC and polycystic kidneys is also discussed. |
5,179 | Clinical predictors of conduction disease progression in type I myotonic muscular dystrophy. | Patients with type I myotonic muscular dystrophy (DM1) are at risk for sudden death due to atrioventricular conduction block. We sought to characterize the trends and predictors of time-dependent electrocardiographic (ECG) variations in patients with DM1.</AbstractText>Seventy patients with DM1 underwent standard electrocardiography at first evaluation and routine and symptom prompted follow-up. Individual variations in ECG conduction intervals were assessed using spaghetti plots. Clinical predictors of conduction disease progression were assessed using multivariate random effects regression models of panel data clustered by patient and adjusted for heart rate.</AbstractText>Substantial individual variability was noted in time-dependent changes in PR, QRS, and QTc intervals of patients with DM1. Changes in the QTc interval were closely associated with prolongation of the QRS interval. Age, the presence of paroxysmal atrial flutter or fibrillation, and the number of cytosine-thymine-guanine (CTG) repeats were independent positive predictors of time-dependent PR and QRS prolongation during long-term follow-up. Female sex was negatively associated with PR prolongation but positively associated with QTc prolongation. Lower left ventricular ejection fraction was associated with greater QRS interval progression during long-term follow-up but was not predictive of PR interval progression.</AbstractText>Patients with DM1 can develop rapid changes in cardiac conduction intervals. Paroxysmal atrial flutter or fibrillation, older age, and larger CTG expansions predict greater time-dependent PR and QRS interval prolongation and warrant particular attention in the arrhythmic evaluation of this high risk patient subset.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,180 | Effect of substance abuse on defibrillation threshold in patients with implantable cardioverter-defibrillator. | The use of recreational drugs has been observed to have deleterious effects on the heart. The aim of our study was to evaluate the effect of substance abuse on the defibrillation threshold (DFT) in patients with implantable cardioverter-defibrillators (ICDs).</AbstractText>A retrospective analysis was conducted on patients who had undergone ICD placement at a tertiary university medical center in Detroit, Michigan. Subjects were identified based on self-reported drug use and placed into one of the three groups: controls, cocaine, and other illicit drugs. Due to a disparity in race among groups, the main analysis on DFT value was conducted on African-American patients only. Furthermore, exploratory analyses were conducted to investigate the effects of marijuana use and race on DFT values.</AbstractText>A history of cocaine use (n = 17) significantly increases DFT among African Americans (17.3 ± 8 Joule [J] vs 12.5 ± 5 J in cases vs controls, P < 0.05), while previous use of marijuana does not significantly influence DFT. African-American patients with a history of illicit drug use had indications for ICD implantation at an earlier age and that within the control (nondrug using) group; African Americans (n = 73) had higher DFT compared to Caucasians (n = 32), (14.5 ± 0.5 J vs 9.7 ± 0.6 J, P < 0.05).</AbstractText>A history of cocaine use in African Americans with ICD is a risk factor for high DFT and race itself (being African American) may be a risk for high DFT. Use of high-energy ICDs and other DFT lowering techniques may be considered for patients who have used or continue to use cocaine or in whom DFT testing cannot be performed at the time of implantation.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,181 | Contributions of a hemodynamic sensor embedded in an atrial lead in a porcine model. | Preliminary studies have revealed a high correlation between peak endocardial acceleration (PEA) measured with a sensor embedded in a ventricular lead and human cardiac contractility. In this study we assessed (1) the contributions made by measurements of PEA1, an index of ventricular systolic contraction, from the right atrium, and (2) the feasibility of recording a fourth component of PEA (PEA4), coincident with atrial contraction and corresponding to the phonocardiographic fourth heart sound.</AbstractText>We placed a PEA sensor embedded at the tip of a right atrial lead in 9 pigs. A 7F Millar catheter tip micromanometer was introduced into the left ventricular (LV) cavity to measure dP/dt(max). Myocardial contractility was increased by infusion of dobutamine and depressed by the infusion of esmolol. We searched, during VDD pacing, for PEA4 following atrial systole, while gradually lengthening the atrioventricular delay. Ventricular fibrillation was then triggered by rapid stimulation.</AbstractText>The changes in PEA1 were correlated with the changes in LV dP/dt(max) (r = 0.91; P < 0.001). A low-frequency component of the endocardial signal (PEA4) was visible approximately 50 milliseconds after the atrial electrogram in all experiments. Following the induction of ventricular fibrillation, PEA4 remained visible on the endocardial recording, simultaneous with the sensed atrial electrogram.</AbstractText>This study confirms the merit of embedding a PEA sensor in an atrial lead. The exploitation of the information provided by the PEA1 signal remains pertinent and the possibility to record an additional PEA4 component offers the perspective of new clinical applications.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,182 | Temporal associations between thoracic volume overload and malignant ventricular arrhythmias: a study of intrathoracic impedance. | Acute exacerbations of heart failure (HF) are believed to trigger malignant ventricular arrhythmias, but the temporal association between fluid accumulation and ventricular arrhythmias has not been evaluated in an objective manner. We hypothesized that increased intrathoracic fluid accumulation in patients with HF, as measured by an index of intrathoracic impedance, is associated with an increased risk of ventricular arrhythmias.</AbstractText>We analyzed interrogations in a cohort of 96 patients with left ventricular dysfunction (EF ≤ 35%) with devices that monitor intrathoracic impedance (OptiVol fluid index). Treated episodes of ventricular tachycardia or fibrillation (VT/VF) were adjudicated and stratified according to predetermined fluid index thresholds (OptiVol indices of 15, 30, 45, 60 Ω-days). VT/VF episodes occurred in 16 patients (17%). VT/VF was more common on days when the fluid index was elevated using threshold values of 15, 30, and 45 Ω-days (P = 0.006, 0.04, 0.02, respectively). There were no differences in the percent of time above any threshold between patients with and without VT/VF.</AbstractText>In patients with HF who develop VT/VF, volume overload, as detected by an index incorporating changes in intrathoracic impedance, was temporally associated with malignant ventricular tachyarrhythmias.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,183 | Severe vasospastic angina with ventricular fibrillation suggested by iodine-123 beta-methyl-p-iodophenyl-pentadecanoic acid in a young woman. | Iodine-123 beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) imaging is useful to diagnose recent myocardial ischemia. A 27-year-old woman was admitted to our hospital because of aborted cardiac arrest due to ventricular fibrillation. She underwent BMIPP imaging in order to rule out ischemic heart disease. Reduced BMIPP uptake was observed in the inferoseptal segments. Coronary angiography revealed insignificant lesions, and a severe coronary spasm was provoked in the right coronary artery by an intracoronary injection of acetylcholine. The etiology of ventricular fibrillation in this case was considered to be vasospastic angina. The application of BMIPP imaging helped diagnose fatal vasospastic angina in this case. |
5,184 | Spontaneous resolution of sinoatrial exit block and atrioventricular dissociation in a child with dengue fever. | Cardiac rhythm abnormalities, including ventricular arrhythmia, atrial fibrillation and atrioventricular block, have been observed during the acute stage of dengue haemorrhagic fever. Atrioventricular or complete heart block can be fatal and may require a temporary pacemaker. We report a ten-year-old girl who presented with dengue haemorrhagic fever with sinoatrial block and atrioventricular dissociation that had a spontaneous resolution. |
5,185 | Pharmacological testing in the diagnosis of arrhythmias. | Pharmacological testing has several indications in the diagnosis of arrhythmia. It is used for the diagnosis of bradycardia-related syncope either during non invasive tests as adenosine triphosphate (ATP) for the diagnosis of vasovagal syncope, but also for the diagnosis of sick sinus syndrome or isoproterenol infusion during the head up tilt test to induce a vasovagal syncope or during electrophysiological study to look for infrahisian AV block or organic sick sinus syndrome after injection of Ajmaline or to know if sick sinus syndrome or suprahisian AV block are reversible after atropine and are vagal-related. It is used for the diagnosis of supraventricular and ventricular tachycardia; isoproterenol is largely used generally during electrophysiological study. The infusion of isoproterenol is required in exercise-related arrhythmias, in arrhythmogenic right ventricular cardiomyopathy, in idiopathic ventricular tachycardia and in idiopathic dilated cardiomyopathy. ATP can be used to induce a vagal-related atrial fibrillation and may help to differentiate a reentry through accessory pathway or AV nodal re-entrant tachycardia. It is used for the detection and the evaluation of prognosis of some diseases at risk of sudden death. Isoproterenol infusion is required in the preexcitation syndrome to look for the shortening of accessory refractory period. Ajmaline or flecaïnide injection is mandatory in the family of a patient with a Brugada syndrome to detect the disease. |
5,186 | Primary electrical diseases diagnosis, genetic and management. | Primary electrical diseases or channelopathies are inherited genetic alterations of the cell ionic and electrical behavior leading to various cardiac arrhythmias carrying the risk of sudden death. A descriptive review of the successively described channelopathies is made in this article, with emphasis on the clinical manifestations, the genetic background and the currently accepted therapeutic options. |
5,187 | Genetic Basis of Ventricular Arrhythmias. | Sudden cardiac death (SCD) is a leading cause of total and cardiovascular mortality, and ventricular fibrillation is the underlying arrhythmia in the majority of cases. In the young, where the incidence of SCD is low, a great proportion of SCDs occur in the context of inherited disorders such as cardiomyopathy or primary electrical disease, where a monogenic hereditary component is a strong determinant of risk. Marked advancement has been made over the past 15 years in the understanding of the genetic basis of the primary electrical disorders, and this has had an enormous impact on the management of these patients. At older ages, the great majority of SCDs occur in the context of acute myocardial ischemia and infarction. Although epidemiologic studies have shown that heritable factors also determine risk in these cases, inheritance is likely complex and multifactorial, and progress in understanding the genetic and molecular mechanisms that determine susceptibility to these arrhythmias, affecting a greater proportion of the population, has been very limited. We review the most recent insights gained into the genetic basis of both the monogenic and the more complex ventricular arrhythmias. |
5,188 | Successful use of ivabradine in a case of exaggerated autonomic dysfunction. | We present a 30-year-old male with complex and predominantly cardiovascular autonomic dysfunction. He had frequent syncopal attacks and paroxysmal atrial fibrillation (PAF). Physical, electrocardiographic, and echocardiographic findings were unremarkable. Syncopal attacks were precipitated by emotional stress, upright position, and micturition. Electrocardiograms obtained immediately after syncopal events revealed PAF with a low ventricular rate, which spontaneously returned to sinus rhythm without any medication. Syncopal events were suggestive of postural orthostatic tachycardia syndrome (POTS), were induced during upright position, and were associated with a sudden increase in heart rate to approximately 140 beats per minute and a sudden drop in blood pressure. Syncope was also induced during carotid sinus massage (CSM) in the upright position. It was thought that cardiac autonomic dysfunction, with POTS as the main component, was responsible for this clinical condition. Syncopal episodes increased in frequency during treatment with metoprolol. Treatment with ivabradine (5 mg twice a day) resulted in disappearance of syncopal episodes both during upright position and CSM. During six months of follow-up, the patient remained asymptomatic without syncope or atrial fibrillation. |
5,189 | Extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest: A review of the Japanese literature. | Although favourable outcomes in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest have been frequently reported in Japanese journals since the late 1980s, there has been no meta-analysis of ECPR in Japan. This study reviewed and analysed all previous studies in Japan to clarify the survival rate of patients receiving ECPR.</AbstractText>Case reports, case series and abstracts of scientific meetings of ECPR for out-of-hospital cardiac arrest written in Japanese between 1983 and 2008 were collected. The characteristics and outcomes of patients were investigated, and the influence of publication bias of the case-series studies was examined by the funnel-plot method.</AbstractText>There were 1282 out-of-hospital cardiac arrest patients, who received ECPR in 105 reports during the period. The survival rate at discharge given for 516 cases was 26.7±1.4%. The funnel plot presented the relationship between the number of cases of each report and the survival rate at discharge as the reverse-funnel type that centred on the average survival rate. In-depth review of 139 cases found that the rates of good recovery, mild disability, severe disability, vegetative state, death at hospital discharge and non-recorded in all cases were 48.2%, 2.9%, 2.2%, 2.9%, 37.4% and 6.4%, respectively.</AbstractText>Based on the results of previous reports with low publication bias in Japan, ECPR appears to provide a higher survival rate with excellent neurological outcome in patients with out-of-hospital cardiac arrest.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,190 | Cardiac safety of conducted electrical devices in pigs and their effect on pacemaker function. | The aims of this study are to evaluate the cardiac safety of the Stinger S-200 Conducted Energy Weapon Device (CED) (Stinger Systems, Tampa, Fla) on a human-sized pig model and to test the effect of various commercially available CEDs, specifically the Stinger S-200, TASER M26 (Taser International, Scottsdale, Ariz), and TASER X26 on pacemaker function.</AbstractText>Two groups of pigs, divided based on weight as group 1 (n = 3, 67.3 ± 4.7 kg) and group 2 (n = 3, 89.3 ± 1.2 kg), were used. In protocol 1, the Stinger S-200 was applied in multiple different orientations to simulate possible field scenarios across the heart. In protocol 2, a single-chamber bipolar lead connected to a pacemaker was placed in the right ventricle of the pig, and different CEDs were applied to test the pacemaker function during CED application.</AbstractText>In protocol 1, the S-200 was applied a total of 216 times in the 6 pigs, and neither episodes of ventricular fibrillation nor episodes of sustained ventricular tachycardia were noted. In protocol 2, the CED discharges (1) were recognized by the pulse generator and sensed as either high-rate atrial or ventricular activity, (2) did not affect the native rhythm, (3) did not conduct down the lead systems to cause any extra systoles, and (4) had no effect on paced rhythm.</AbstractText>In this model, the application of the S-200 in various orientations across the heart did not result in any sustained abnormal cardiac rhythms. None of the tested CEDs adversely affected the functioning of the tested pacemaker. Stinger Systems has now replaced the S-200 with the S-200T with a different output.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,191 | Pharmacology of cardiac potassium channels. | Cardiac K(+) channels are cardiomyocyte membrane proteins that regulate K(+) ion flow across the cell membrane on the electrochemical gradient and determine the resting membrane potential and the cardiac action potential morphology and duration. Several K(+) channels have been well studied in the human heart. They include the transient outward K(+) current I(to1), the ultra-rapidly activating delayed rectifier current I(Kur), the rapidly and slowly activating delayed rectifier currents I(Kr) and I(Ks), the inward rectifier K(+) current I(K1), and ligand-gated K(+) channels, including adenosine-5'-triphosphate (ATP)-sensitive K(+) current (I(KATP)) and acetylcholine-activated current (I(KACh)). Regional differences of K(+) channel expression contribute to the variable morphologies and durations of cardiac action potentials from sinus node and atrial to ventricular myocytes, and different ventricular layers from endocardium and midmyocardium to epicardium. They also show different responses to endogenous regulators and/or pharmacological agents. K(+) channels are well-known targets for developing novel anti-arrhythmic drugs that can effectively prevent/inhibit cardiac arrhythmias. Especially, atrial-specific K(+) channel currents (I(Kur) and I(KACh)) are the targets for developing atrial-selective anti-atrial fibrillation drugs, which has been greatly progressed in recent years. This chapter concentrates on recent advances in intracellular signaling regulation and pharmacology of cardiac K(+) channels under physiological and pathophysiological conditions. |
5,192 | The ryanodine receptor in cardiac physiology and disease. | According to the American Heart Association it is estimated that the United States will spend close to $39 billion in 2010 to treat over five million Americans suffering from heart failure. Patients with heart failure suffer from dyspnea and decreased exercised tolerance and are at increased risk for fatal ventricular arrhythmias. Food and Drug Administration -approved pharmacologic therapies for heart failure include diuretics, inhibitors of the renin-angiotensin system, and β-adrenergic receptor antagonists. Over the past 20 years advances in the field of ryanodine receptor (RyR2)/calcium release channel research have greatly advanced our understanding of cardiac physiology and the pathogenesis of heart failure and arrhythmias. Here we review the key observations, controversies, and discoveries that have led to the development of novel compounds targeting the RyR2/calcium release channel for treating heart failure and for preventing lethal arrhythmias. |
5,193 | Right ventricular dysfunction is a strong predictor of developing atrial fibrillation in acutely decompensated heart failure patients, ACAP-HF data analysis. | Heart failure and atrial fibrillation (AFib) are the twin epidemics of modern cardiovascular disease. The incidence of new-onset AFib in acute decompensated heart failure (ADHF) patients is difficult to predict and the short- and long-term outcomes of AFib in a cohort of patients admitted with ADHF are unknown.</AbstractText>A total of 904 patients admitted with ADHF were studied. Incidence of AFib on admission was recorded and a multivariate analysis was performed using echocardiographic parameters to specify the predictors of AFib incidence in this cohort. In 904 ADHF patients (57% male, mean age 69 ± 14 years), 81% had history of hypertension, 40% were diabetics, and 51% were smokers. A total of 63% of the patients had known heart failure (HF) with mean ejection fraction of 34% ± 21%, and 33% of the patients had ischemic cardiomyopathy as the etiology of HF. Echocardiographic parameters were: left atrial (LA) diameter 4.5 ± 0.8 cm, left ventricular end-systolic 4.1 ± 1.3 cm, left ventricular end-diastolic 5.3 ± 1.1 cm. Right ventricular dysfunction (RVD) was present in 34% of the patients. A total of 191 (21%) patients subsequently developed AFib with two thirds of the cases occurring in patients with RVD. Using a univariate analysis, older age (OR 1.02; P < .0001), history of HF (OR 2.93; P < .0001), LA dilation (OR 1.58; P < .0001), the presence of left ventricular hypertrophy (OR 3.01, P < .0001), and RVD (OR 4.93; P < .00001) were the strongest predictors for AFib. Controlling for LA size and left ventricular hypertrophy using a forward stepwise regression, RVD remained the strongest predictor (OR 4.45; P < .0001). Patients with RVD had more events (cardiac readmission and mortality) than those with normal RV (56% versus 38%; P < .00001), notably; all-cause mortality was 4.7%/year in the abnormal RV group versus 2.9%/year in the normal RV group; P < .05. RV function analyses by echocardiography further risk stratified these patients based on their rhythm categorizing those patients with abnormal RV and AFib as the ones with the worse prognosis.</AbstractText>RV dysfunction is a strong predictor for developing AFib in acutely decompensated systolic failure patients. Patients with AFib and RVD have the worse outcome specially when is combined with LV dysfunction, therefore; evaluation of RV function may substantiate the difference in HF prognosis.</AbstractText>Copyright © 2010 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,194 | Recurrent post-partum coronary artery dissection. | Coronary artery dissection is a rare but well-described cause for myocardial infarction during the post-partum period. Dissection of multiple coronary arteries is even less frequent. Here we present a case of recurrent post-partum coronary artery dissections. This unusual presentation poses unique problems for management. A 35 year-old female, gravida 3 para 2, presented with myocardial infarction 9 weeks and 3 days post-partum. Cardiac catheterization demonstrated left anterior descending (LAD) dissection but an otherwise normal coronary anatomy. The lesion was treated with four everolimus eluting stents. Initially the patient made an unremarkable recovery until ventricular fibrillation arrest occurred on the following day. Unsynchronized cardioversion restored a normal sinus rhythm and repeat catheterization revealed new right coronary artery (RCA) dissection. A wire was passed distally, but it was unclear whether this was through the true or false lumen and no stents could be placed. However, improvement of distal RCA perfusion was noted on angiogram. Despite failure of interventional therapy the patient was therefore treated conservatively. Early operation after myocardial infarction has a significantly elevated risk of mortality and the initial dissection had occurred within 24 hours. This strategy proved successful as follow-up transthoracic echocardiography after four months demonstrated a preserved left ventricular ejection fraction of 55-60% without regional wall motion abnormalities. The patient remained asymptomatic from a cardiac point of view. |
5,195 | [Comparison of treatment effectiveness of implantable cardioverter defibrillator in patients undergoing defibrillation threshold testing at the time of implantation versus no defibrillation threshold testing]. | Inability to perform defibrillation threshold (DFT) testing during implantable cardioverter defibrillator (ICD) implantation due to comorbidities may influence long-term survival.</AbstractText>Retrospective review (2005-2007) identified 142 patients undergoing ICD implantation without DFT testing (No-DFT group). A control group consisting of 290 patients undergoing standard DFT testing (DFT group) was compared to the first group in terms of appropriate shocks, clinical shock efficacy and all-cause mortality. The primary and secondary prophylactic therapy were performed to the estimation.</AbstractText>DFT testing was withheld due to atrial fibrillation with inability to exclude left atrial thrombus, left ventricular thrombus, congestive heart disease and(or) ischemia, hypotension and absent of anesthesiologist. The No-DFTgroup had a similar appropriate shock rate, but lower total survival (79.1% vs. 91.2%, p = 0.01) than the DFT group. In secondary prophylactic therapy, the No-DFT group had a higher incidence of sudden death (7.6% vs. 4.3%, p = 0.03) compared to the DFT group.</AbstractText>The overall mortality was higher in the No-DFT group and number of sudden death in secondary prophylactic therapy. DFT testing should therefore remain the standard of care. Nevertheless, ICD therapy should not be withheld in patients who meet appropriate implant criteria simply on the basis of clinical scenarios that preclude routine DFT testing.</AbstractText> |
5,196 | Defibrillation in children. | Defibrillation is the only effective treatment for ventricular fibrillation (VF). Optimal methods for defibrillation in children are derived and extrapolated from adult data. VF occurs as the initial rhythm in 8-20% of pediatric cardiac arrests. This has fostered a new interest in determining the optimal technique for pediatric defibrillation. This review will provide a brief background of the history of defibrillation and a review of the current literature on pediatric defibrillation. The literature search was performed through PubMed, using the MeSH headings of cardiopulmonary resuscitation, defibrillation and electric countershock. The authors' personal bibliographic files were also searched. Only published articles were chosen. The recommended energy dose has been 2 J/kg for 30 years, but recent reports may indicate that higher dosages may be more effective and safe. In 2005, the European Resuscitation Council recommended 4 J/kg as the initial dose, without escalation for subsequent shocks. Automated external defibrillators are increasingly used for pediatric cardiac arrest, and available reports indicate high success rates. Additional research on pediatric defibrillation is critical in order to be able to provide an equivalent standard of care for children in cardiac arrest and improve outcomes. |
5,197 | Better outcome after pediatric resuscitation is still a dilemma. | Pediatric cardiac arrest is not a single problem. Although most episodes of pediatric cardiac arrest occur as complications and progression of respiratory failure and shock. Sudden cardiac arrest may result from abrupt and unexpected arrhythmias. With a better-tailored therapy, we can optimize the outcome. In the hospital, cardiac arrest often develops as a progression of respiratory failure and shock. Typically half or more of pediatric victims of in-hospital arrest have pre-existing respiratory failure and one-third or more have shock, although these figures vary somewhat among reporting hospitals. When in-hospital respiratory arrest or failure is treated before the development of cardiac arrest, survival ranges from 60% to 97%. Bradyarrthmia, asystole or pulseless electric activity (PEA) were recorded as an initial rhythm in half or more of the recent reports of in-hospital cardiac arrest, with survival to hospital discharge ranging from 22% to 40%. Data allowing characterization of out of hospital pediatric arrest are limited, although existing data support the long-held belief that as with hospitalized children, cardiac arrest most often occurs as a progression of respiratory failure or shock to cardiac arrest with bradyasystole rhythm. Although VF (Ventricular fibrillation, is a very rapid, uncoordinated, ineffective series of contractions throughout the lower chambers of the heart. Unless stopped, these chaotic impulses are fatal) and VT (Ventricular tachycardia is a rapid heartbeat that originates in one of the ventricles of the heart. To be classified as tachycardia, the heart rate is usually at least 100 beats per minute) are not common out-of-cardiac arrest in children, they are more likely to be present with sudden, witnessed collapse, particularly among adolescents. Pre-hospital care till the late 1980s was mainly concerned with adult care, and the initial focus for pediatric resuscitation was provision of oxygen and ventilation, with initial rhythm at the time of emergency medical services arrival being infrequently recorded. In the 1987 series, pre-hospital pediatric cardiac arrest demonstrated asystole in 80%, PEA in 10.5% and VF or VT in 9.6%. Only 29% arrests were witnessed, however, and death in many victims was caused by sudden infant death syndrome. |
5,198 | Utilization of Electrocardiographic P-wave Duration for AV Interval Optimization in Dual-Chamber Pacemakers. | Empiric programming of the atrio-ventricular (AV) delay is commonly performed during pacemaker implantation. Transmitral flow assessment by Doppler echocardiography can be used to find the optimal AV delay by Ritter's method, but this cannot easily be performed during pacemaker implantation. We sought to determine a non-invasive surrogate for this assessment. Since electrocardiographic P-wave duration estimates atrial activation time, we hypothesized this measurement may provide a more appropriate basis for programming AV intervals.</AbstractText>A total of 19 patients were examined at the time of dual chamber pacemaker implantation, 13 (68%) being male with a mean age of 77. Each patient had the optimal AV interval determined by Ritter's method. The P-wave duration was measured independently on electrocardiograms using MUSE® Cardiology Information System (version 7.1.1). The relationship between P-wave duration and the optimal AV interval was analyzed.</AbstractText>The P-wave duration and optimal AV delay were related by a correlation coefficient of 0.815 and a correction factor of 1.26. The mean BMI was 27. The presence of hypertension, atrial fibrillation, and valvular heart disease was 13 (68%), 3 (16%), and 2 (11%) respectively. Mean echocardiographic parameters included an ejection fraction of 58%, left atrial index of 32 ml/m(2), and diastolic dysfunction grade 1 (out of 4).</AbstractText>In patients with dual chamber pacemakers in AV sequentially paced mode and normal EF, electrocardiographic P-wave duration correlates to the optimal AV delay by Ritter's method by a factor of 1.26.</AbstractText> |
5,199 | Predictors for permanent pacing after transcatheter aortic valve implantation. | Transcatheter aortic valve implantation (TAVI) is a new treatment strategy for patients with symptomatic aortic stenosis who are high risk for traditional surgical aortic valve replacement. The incidence of conduction system abnormalities after the procedure is significant. We examine our experience with CoreValve TAVI focusing on electrocardiographic changes found pre-, peri-, and postintervention.</AbstractText>During 2007-08 we undertook 33 cases utilizing the CoreValve revalving system (CoreValve, Paris, France). Assessment of ECGs, with particular reference to the PR and QRS duration, was made daily during each patient's hospital stay.</AbstractText>Patients were aged 81.7 ± 6.7 years and the majority were male (57%). Baseline cardiac rhythm was sinus (n = 28, 80%); atrial fibrillation (n = 6, 18%) or ventricular paced (n = 1, 3%). Following CoreValve implantation, prolongation of both the PR interval and QRS duration was seen. Preprocedural PR interval was 193.5 ± 38.7 ms and QRS interval preprocedure was 115.3 ± 24.8 ms. PR interval increased after the procedure by 23.5 ± 23.9 ms and peaked at day 4 with a mean increase of 66.1 ± 72.7 ms. QRS duration increased by a mean of 30.6 ± 26.1 ms postprocedure and remained stable thereafter during the remaining hospital stay. The need for PPM insertion was partially predicted by pre-procedural QRS morphology: patients with pre-existing right bundle branch block had an 83% chance of requiring a permanent pacemaker (P < 0.01 OR 28 95%CI 2.4-326.7); those with LBBB had a 33% chance of requiring a pacemaker (P = ns OR 2.3 95%CI 0.2-34.9). Patients undergoing the procedure later in our experience showed a decreased incidence of pacing (P = 0.046 OR 0.36 95% CI 0.07-1.82). Pre-procedural annulus measurements also predicted the requirement for pacing with larger annulus sizes more likely to require a pacemaker (P = 0.044 OR 3.3 95% CI 0.63-17.6). The requirement for pacing was not predicted by age, baseline PR interval or gender. Requirement for pacing overall was 32% with an additional 13% having had a pacemaker inserted prior to the TAVI.</AbstractText>CoreValve insertion was associated with an increase in PR interval and QRS duration. PR interval continued to rise during admission, peaking on Day 4 post procedure, making a prolonged period of monitoring highly desirable. There was a significant requirement for permanent pacing, which was predicted by pre-procedural QRS morphology, annulus measurement, and the learning curve. © 2010 Wiley-Liss, Inc.</AbstractText> |
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