Dirk Böcker

Long-Term Prognosis of Individuals With Right Precordial ST-Segment–Elevation Brugada Syndrome

Background—Brugada syndrome is an arrhythmogenic disease characterized by an ECG pattern of ST-segment elevation in the right precordial leads and an increased risk of sudden cardiac death as a result of ventricular fibrillation. Controversy exists with regard to risk stratification and therapeutic management, particularly in asymptomatic individuals. Methods and Results—A total of 212 individuals (mean age, 45±6 years) with a type 1 Brugada ECG pattern were studied. Of these, 123 (58%) were asymptomatic, 65 (31%) had ≥1 syncope of unknown origin, and 24 (11%) had to be resuscitated because of ventricular fibrillation. In 125 individuals (59%), a spontaneous type 1 ECG was recorded. In the remaining, drug challenge with a class I antiarrhythmic agent unmasked a Brugada ECG. The mean ST elevation was 2.3±1.2 mm in symptomatic patients and 1.9±1.5 mm in asymptomatic individuals (P=0.04). During a mean follow-up of 40±50 months, 4 of the 24 patients (17%) with aborted sudden cardiac death and 4 of 65 (6%) with a prior syncope had a recurrent arrhythmic event, whereas only 1 of 123 asymptomatic individuals (0.8%) had a first arrhythmic event. Four of 9 patients with arrhythmic events during follow-up were not inducible during programmed electrical stimulation. A previous history of aborted sudden death or syncope and the presence of a spontaneous type 1 ECG were predictors of adverse outcome. Conclusions—The present study reports data on a large population of individuals with a type 1 Brugada ECG pattern with the longest follow-up reported so far. A very low incidence of severe arrhythmic events, particularly in asymptomatic individuals, was found during follow-up. In the presence of very few arrhythmic events on follow-up, programmed electrical stimulation showed very little accuracy in predicting outcome.

Implantable Cardioverter/Defibrillator Therapy in Arrhythmogenic Right Ventricular Cardiomyopathy Single-Center Experience of Long-Term Follow-Up and Complications in 60 Patients

Background—Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of ventricular tachycardia (VT) and cardiac arrest in young patients. We hypothesized that treatment with implantable cardioverter/defibrillators (ICDs) is safe and improves the long-term prognosis of ARVC patients at high risk of sudden death. Methods and Results—Sixty patients with ARVC (aged 43±16 years) were treated with transvenous ICD systems. Despite a higher number of right ventricular sites tested for adequate lead positions (P <0.05), lower R-wave amplitudes (P <0.001) were achieved in ARVC patients compared with other entities. During follow-up of 80±43 months (396 patient-years), event-free survival was 49%, 30%, 26%, and 26% for appropriate ICD therapies and 79%, 64%, 59%, and 56% for potentially fatal VT (>240 bpm) after 1, 3, 5, and 7 years, respectively. Multivariate analysis identified extensive right ventricular dysfunction as an independent predictor of appropriate ICD discharge. Fifty-three adverse events occurred in 37 patients during the perioperative (n=10) or follow-up (n=43) period, mainly related to the leads (n=31 in 21 patients). No lead perforation was observed. Freedom from adverse events was 90%, 78%, 56%, and 42% and freedom from lead-related complications was 95%, 85%, 74%, and 63% after 1, 3, 5, and 7 years, respectively. Conclusions—These results strongly suggest an improvement in long-term prognosis by ICD therapy in high-risk patients with ARVC. However, meticulous placement and long-term observation of transvenous lead performance with focus on sensing function are required for the prevention and/or early recognition of disease progression and lead-related morbidity during long-term follow-up of ICD therapy in ARVC.

Anterior-posterior versus anterior-lateral electrode positions for external cardioversion of atrial fibrillation: a randomised trial

BACKGROUND External cardioversion is a readily available treatment for persistent atrial fibrillation. Although anatomical and electrophysiological considerations suggest that an anterior-posterior electrode position should create a more homogeneous shock-field gradient throughout the atria than an anterior-lateral position, both electrode positions are equally recommended for external cardioversion in current guidelines. We undertook a randomised trial comparing the two positions with the endpoint of successful cardioversion. METHODS 108 consecutive patients (mean age 60 years [SD 16]) with persistent atrial fibrillation (median duration 5 months, range 0.1-120) underwent elective external cardioversion by a standardised step-up protocol with increasing shock strengths (50-360 J). Electrode positions were randomly assigned as anterior-lateral or anterior-posterior. If sinus rhythm was not achieved with 360 J energy, a single cross-over shock (360 J) was applied with the other electrode configuration. A planned interim analysis was done after these patients had been recruited; it was by intention to treat. FINDINGS Cardioversion was successful in a higher proportion of the anterior-posterior than the anterior-lateral group (50 of 52 [96%] vs 44 of 56 [78%], difference 23.7% (95% CI 9.1-37.8, p=0.009). Cross-over from the anterior-lateral to the anterior-posterior electrode position was successful in eight of 12 patients, whereas cross-over in the other direction was not successful (two patients). After cross-over, cardioversion was successful in 102 of 108 randomised patients (94%). INTERPRETATION An anterior-posterior electrode position is more effective than the anterior-lateral position for external cardioversion of persistent atrial fibrillation. These results should be considered in clinical practice, for the design of defibrillation electrode pads, and when guidelines for cardioversion of atrial fibrillation are updated.

Leitlinien zur Implantation von Defibrillatoren

Die vorliegenden Leitlinien zur Implantation von Defibrillatoren wurden in Uberarbeitung der Leitlinien der Deutschen Gesellschaft fur Kardiologie, Herz und Kreislaufforschung, wie sie 1993 publiziert worden sind, erstellt, basierend auf einer sorgfaltigen Analyse der wissenschaftlichen Daten zur aktuellen Therapie ventrikularer Tachyarrhythmien. Auch in Zukunft sollen diese Leitlinien in regelmasigen Abstanden revidiert werden, wenn der wissenschaftliche Erkenntnisstand dies erforderlich macht.

QRS duration: a simple marker for predicting cardiac mortality in ICD patients with heart failure

Background: Patients resuscitated from ventricular tachyarrhythmias benefit from implantable cardioverter-defibrillators (ICDs) as opposed to medical treatment. Patients with increased QRS duration receiving an ICD in the presence of heart failure are at greatest risk of cardiac death and benefit most from ICD therapy. Objective: To determine whether an increased QRS duration predicts cardiac mortality in ICD recipients. Design: Consecutive patients with heart failure in New York Heart Association functional class III were grouped according to QRS duration (< 150 ms, n = 139, group 1; v ⩾ 150 ms, n = 26, group 2) and followed up for (mean (SD)) 23 (20) months. Patients: 165 patients were studied (80% men, 20% women); 73% had coronary artery disease and 18% had dilated cardiomyopathy. Their mean age was 62 (10) years and mean ejection fraction (EF) was 33 (14)%. They presented either with ventricular tachycardia (VT) or ventricular fibrillation (VF). Main outcome measures: Overall and cardiac mortality; recurrence rates of VT, fast VT, or VF. Results: Mean left ventricular EF did not differ between group 1 (33 (13)%) and group 2 (31 (15)%). Forty patients died (34 cardiac deaths). There was no difference in survival between patients with EF > 35% and ⩽ 35%. Cardiac mortality was significantly higher in group 2 than in group 1 (31.3% at 12 months and 46.6% at 24 months, v 9.5% at 12 months and 18.2% at 24 months, respectively; p = 0.04). The recurrence rate of VT was similar in both groups. Conclusions: Within subgroups at highest risk of cardiac death, QRS duration—a simple non-invasive index—predicts outcome in ICD recipients in the presence of heart failure.

Clusters of ventricular tachycardias signify impaired survival in patients with idiopathic dilated cardiomyopathy and implantable cardioverter defibrillators.

OBJECTIVES This retrospective study was undertaken to provide data on occurrence, significance and therapy of ventricular tachyarrhythmia (VT) clusters (VTCs) in patients with dilated cardiomyopathy (DCM) and implantable cardioverter defibrillators (ICDs). BACKGROUND Data on the clinical significance of VTCs are lacking in patients with DCM and ICDs. METHODS Baseline characteristics of 106 consecutive patients with DCM and ICDs were prospectively collected, and chart reviews and episode data retrospectively analyzed. A VTC was defined as > or =3 sustained VTs/24 h. RESULTS During a mean follow-up of 33+/-23 months, 73 patients (68.9%) had recurrent VT or ventricular fibrillation (VF), 43 patients (40.6%) suffered only single VTs and 30 patients (28.3%) experienced 52 clusters of VTs. Actuarial survival free of VT or VF was 44.6%, 33.0% and 26.5%, and survival free of VTC was 77.3%, 72.2% and 67.1% after one, two and three years, respectively. Independent predictors of VT clusters were heart failure before ICD implantation (p = 0.033), presenting monomorphic VT (p = 0.044), EF <0.40 (p = 0.014) and inducible mVT, especially with right bundle branch block and superior axis configuration (p<0.001). Survival free of recurrent VTCs was 50.8%, 38.1% and 19.0% after one, two and three years, respectively. Once a VTC had occurred, only 56.7%, 46.4%, 30.9% and 15.5% of patients survived and were not transplanted after one, two, three and four years, respectively. Survival was even more reduced if a VTC was associated with cardiac decompensation: 65.6% and 21.9% after one and two years, respectively. CONCLUSIONS Despite antiarrhythmic intervention, clusters of VTs occur and recur frequently in patients with DCM. They signify impaired survival, especially if they are associated with cardiac decompensation, and may be a harbinger of progressive myocardial deterioration rather than a primarily arrhythmic problem. The benefit of ICD therapy may therefore be low in these patients.

Do patients with an implantable defibrillator live longer

OBJECTIVES This study was done to provide information on the potential benefit of implantable cardioverter-defibrillator therapy regarding sudden and arrhythmia-related deaths and to examine whether such therapy improves survival. BACKGROUND Implantation of automatic cardioverter-defibrillators is reported to abort sudden cardiac death due to malignant tachyarrhythmias. METHODS Between 1989 and 1992, 107 patients were screened for implantation of a third-generation implantable cardioverter-defibrillator combined with endocardial leads. Mean age was 57 +/- 13 years and mean ejection fraction was 40 +/- 15%. Sudden death, total arrhythmia-related death and total cardiac death were compared with the occurrence of fast ventricular tachyarrhythmias (> 240 beats/min), assuming that most of these arrhythmias would have been fatal without treatment by the implantable cardioverter-defibrillator. RESULTS The surgical mortality rate was 2.7% in all 107 patients and 1% in the 99 patients who qualified for endocardial leads. During a follow-up period of 12 +/- 8 months, actuarial survival rate free of events at 6 months as well as at 12 and 18 months was 100% for sudden death, 97% for total arrhythmia-related death and 95% for total cardiac death. In contrast, after 6, 12 and 18 months, the rate of survival free of fast ventricular tachycardia was only 83%, 74% and 69%, respectively, and the rate of survival free of any ventricular tachyarrhythmia was only 59%, 49% and 40%, respectively. CONCLUSIONS The outcome of patients treated with an implantable cardioverter-defibrillator and endocardial defibrillation leads is excellent. For many patients, this treatment is probably lifesaving.

Randomized, double blind study of non-excitatory, cardiac contractility modulation electrical impulses for symptomatic heart failure

AIMS We performed a randomized, double blind, crossover study of cardiac contractility modulation (CCM) signals in heart failure patients. METHODS AND RESULTS One hundred and sixty-four subjects with ejection fraction (EF) < 35% and NYHA Class II (24%) or III (76%) symptoms received a CCM pulse generator. Patients were randomly assigned to Group 1 (n = 80, CCM treatment 3 months, sham treatment second 3 months) or Group 2 (n = 84, sham treatment 3 months, CCM treatment second 3 months). The co-primary endpoints were changes in peak oxygen consumption (VO2,peak) and Minnesota Living with Heart Failure Questionnaire (MLWHFQ). Baseline EF (29.3 +/- 6.7% vs. 29.8 +/- 7.8%), VO2,peak (14.1 +/- 3.0 vs. 13.6 +/- 2.7 mL/kg/min), and MLWHFQ (38.9 +/- 27.4 vs. 36.5 +/- 27.1) were similar between the groups. VO2,peak increased similarly in both groups during the first 3 months (0.40 +/- 3.0 vs. 0.37 +/- 3.3 mL/kg/min, placebo effect). During the next 3 months, VO2,peak decreased in the group switched to sham (-0.86 +/- 3.06 mL/kg/min) and increased in patients switched to active treatment (0.16 +/- 2.50 mL/kg/min). MLWHFQ trended better with treatment (-12.06 +/- 15.33 vs. -9.70 +/- 16.71) during the first 3 months, increased during the second 3 months in the group switched to sham (+4.70 +/- 16.57), and decreased further in patients switched to active treatment (-0.70 +/- 15.13). A comparison of values at the end of active treatment periods vs. end of sham treatment periods indicates statistically significantly improved VO2,peak and MLWHFQ (P = 0.03 for each parameter). CONCLUSION In patients with heart failure and left ventricular dysfunction, CCM signals appear safe; exercise tolerance and quality of life (MLWHFQ) were significantly better while patients were receiving active treatment with CCM for a 3-month period.

Arrhythmogenic right ventricular cardiomyopathy. Antiarrhythmic drugs, catheter ablation, or ICD?

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of sudden cardiac death and ventricular tachyarrhythmias in young, apparently healthy individuals and athletes. Myocardial atrophy with subsequent fibrofatty replacement predominantly affects right ventricular myocardium and results in global and regional dysfunction as well as areas of slow conduction and dispersion of refractoriness which are prerequisites for reentrant ventricular tachyarrhythmias.Patients affected with ARVC should be excluded from competitive sports and vigorous training. To provide optimal treatment, a detailed diagnostic evaluation and risk stratification are mandatory. Tailored treatment strategies aim at the suppression or effective termination of recurrent ventricular tachyarrhythmias and prevention of sudden death by antiarrhythmic drug therapy, catheter ablation, or implantation of a cardioverter defibrillator (ICD).Antiarrhythmic drugs may be used as a stand-alone treatment to suppress ventricular tachycardia (VT) recurrences in patients with ARVC and low risk of sudden death. Sotalol (preferred) or amiodarone in combination with β-blockers showed the highest efficacy rates. In patients at higher risk, an ICD should be implanted and antiarrhythmic drugs be used only as an adjunct to prevent or suppress frequent VT recurrences and ICD discharges.Catheter ablation using conventional or electroanatomic mapping techniques yields good acute results for eliminating the targeted arrhythmia substrate. However, during the progressive long-term course of ARVC, VT recurrences from new arrhythmia foci are frequent and therefore limit the curative value of catheter ablation. In patients with frequent VT recurrences and ICD discharges, however, catheter ablation plays an important role as a palliative and adjunctive treatment option for arrhythmia suppression.ICD therapy has been increasingly used for secondary and also primary prevention of sudden death in patients with ARVC. In secondary prevention, the ICD has shown to improve the long-term prognosis of patients at high risk of sudden death by effective termination of life-threatening recurrences of ventricular tachyarrhythmias. However, adequate lead placement may be difficult and lead-related complications during long-term follow-up must be taken into account. The role of ICD therapy for primary prevention of sudden death in ARVC is not yet adequately defined.Ongoing international registries will provide important additional data to improve risk stratification and refine treatment algorithms in order to select the best individual treatment for arrhythmia suppression and prevention of sudden death in patients with ARVC.ZusammenfassungDie arrhythmogene rechtsventrikuläre Kardiomyopathie (ARVC) ist eine wesentliche Ursache ventrikulärer Tachyarrhythmien und plötzlicher Herztodesfälle bei jungen, scheinbar herzgesunden Patienten und Sportlern. Durch regionale Atrophie vorwiegend rechtsventrikulären Myokards und nachfolgenden Ersatz durch Fett- und Bindegewebe kommt es neben globalen oder regionalen Funktionsstörungen zu lokaler Verzögerung der Erregungsleitung und Dispersion der Refraktärzeiten des rechten Ventrikels, die eine Grundlage für Reentrymechanismen sind und damit zu den klinisch im Vordergrund stehenden ventrikulären Tachykardien (VT) führen.Patienten mit ARVC sollten vom Leistungssport ausgeschlossen werden und systematisches Training sowie starke körperliche Belastungen vermeiden. Eine detaillierte Diagnostik und Risikostratifikation sind entscheidend für die Planung einer individuellen Therapiestrategie, welche die Behandlung ventrikulärer Arrhythmien und die Prävention des plötzlichen Herztodes zum Ziel hat. Hierzu stehen die antiarrhythmische Pharmakotherapie, die Katheterablation und die Implantation eines Kardioverter-Defibrillators (ICD) zur Verfügung.Bei Patienten mit ARVC und geringem Risiko für plötzlichen Herztod können primär Antiarrhythmika zur Suppres sion ventrikulärer Arrhythmien eingesetzt werden, wobei Sotalol oder Amiodaron in Kombination mit β-Blockern die höchsten Effektivitätsraten aufweisen. Bei Patienten mit hohem Risiko sollte dagegen ein Schutz durch ICD-Implantation erfolgen und eine antiarrhythmische Therapie nur adjuvant zur Suppression häufiger VT-Rezidive eingesetzt werden.Die Katheterablation von VT mit konventionellen und/oder elektroanatomischen Mapping-Techniken liefert bei Patienten mit ARVC gute Akutergebnisse hinsichtlich der Elimination des behandelten Arrhythmiesubstrats. Im Langzeitverlauf kommt es durch die fortschreitende Grunderkrankung jedoch häufig zu VT-Rezidiven aus neu entstehenden Substraten, so dass der kurative Wert der Katheterablation deutlich eingeschränkt ist. Unter palliativen Gesichtspunkten ist die Katheterablation jedoch insbesondere bei Patienten mit häufigen VT-Rezidiven und ICD-Schocks von großem Wert.Bei Patienten mit ARVC und hohem Risiko für plötzlichen Herztod führt die ICD-Therapie zu einer deutlichen Verbesserung der Langzeitprognose, da häufig auftretende lebensbedrohliche VT-Rezidive sicher erkannt und beendet werden. Die Platzierung der rechtsventrikulären Elektrode kann sich jedoch schwierig gestalten. Zudem muss die vor allem elektrodenbezogene Komplikationsrate der ICD-Therapie im Langzeitverlauf bei dem jungen Kollektiv mit ARVC berücksichtigt werden. Die Rolle der ICD-Therapie in der Primärprävention des plötzlichen Herztodes ist bei Patienten mit ARVC bislang nur unzureichend untersucht.Laufende internationale multizentrische Register werden in den kommenden Jahren weitere wichtige Daten zur Risikostratifikation und Therapieeffektivität liefern, so dass erwartet wird, dass derzeit empfohlene Algorithmen zur Behandlung der Arrhythmien und Prävention des plötzlichen Herztodes weiter verbessert werden können.

The 1+1 trial: a prospective trial of a dual- versus a single-chamber implantable defibrillator in patients with slow ventricular tachycardias.

Background—The tachycardia detection interval (TDI) in implantable cardioverter/defibrillators (ICDs) is conventionally programmed according to the slowest documented ventricular tachycardia (VT), with a safety margin of 30 to 60 ms. With this margin, VTs above the TDI may occur. However, longer TDIs are associated with an increased risk of inappropriate therapy. We hypothesized that patients with slow VTs (<200 bpm) may benefit from a long TDI and a dual-chamber detection algorithm compared with a conventionally programmed single-chamber ICD. Methods and Results—Patients with VTs <200 bpm were implanted with a dual-chamber ICD that was randomly programmed to a dual-chamber algorithm and a TDI of ≥469 ms or to a single-chamber algorithm with a TDI 30 to 60 ms above the slowest documented VT cycle length and the enhancement criteria of cycle length variation and acceleration. The primary combined end point was the number of all inappropriate therapies, VTs above the TDI, and VTs with significant therapy delay (>2 minutes). After 6 months, a crossover analysis was performed. Total follow-up was 1 year. One hundred two patients were included in the study. The programmed TDI was 500±36 ms during the dual-chamber phase and 424±63 ms during the single-chamber phase. For the primary end point (inappropriate therapies, VTs above the TDI, or VTs with detection delay), a moderate superiority of the dual-chamber mode was found: Mann-Whitney estimator=0.6661; 95% CI, 0.5565 to 0.7758; P=0.0040. Conclusions—Dual-chamber detection with a longer TDI improves VT detection and does not increase the rate of inappropriate therapies despite a considerable increase in tachycardia burden.