Prevention of immediate reinitiation of atrial tachyarrhythmias by high-rate overdrive pacing: results from a prospective randomized trial

INTRODUCTION: Immediate reinitiation of atrial tachyarrhythmia (IRAT) is an important cause of failure to maintain sinus rhythm. IRAT prevention by overdrive pacing has not been evaluated in a prospective randomized trial. METHODS AND RESULTS: Patients with a DDDRP pacemaker offering temporary atrial overdrive pacing after AT termination (Post Mode Switching Overdrive Pacing [PMOP]) were enrolled into the prospective PIRAT (Prevention of IRAT) trial if paroxysmal AT episodes occurred after implantation. PMOP was randomly activated (120 beats/min for 2 min) or inactive. After 3 months, device memory was interrogated, symptoms and quality of life assessed, and patients crossed over to the alternative treatment arm for another 3 months. Primary study endpoint was the number of AT episodes; secondary endpoints were the cumulative time in AT (AT burden), percentage of AT episodes with IRAT, symptoms, and quality of life with PMOP active versus inactive. In 37 patients (21 men; 69 +/- 9 years), there was no difference in the median number of AT episodes (0.37 vs 0.34 per day), AT burden (both 1%), percentage of episodes with IRAT (30%vs 28%), symptoms, and quality of life during PMOP off versus on. With PMOP active, 29% of 439 ATs restarted during and 18% before PMOP intervention. The PMOP-induced rate increase appeared to be associated with IRAT in 9% of AT episodes. CONCLUSION: Automatic overdrive pacing after AT termination did not prevent IRAT, mainly due to insufficient overdrive suppression even at 120 beats/min and the delay between AT termination and PMOP intervention.     

Stroke complicating congenital sick sinus syndrome

We report the case of a patient with congenital sick sinus syndrome complicated by atrial fibrillation and embolic stroke 23 years after the initial diagnosis, at the age of 34 years. Treatment with a dual-chamber pacemaker and oral anticoagulation were initiated; further follow-up was uneventful but pacemaker diagnostics constantly documented asymptomatic recurrences of paroxysmal atrial fibrillation.     

ICD Therapy in Coronary Artery Disease

Abstract 25 years after the first coronary artery patient received an implantable cardioverter defibrillator (ICD), many randomized controlled trials on prophylactic ICD therapy have been conducted. Taken together, these trials allow an evidence-based approach to primary prevention of sudden cardiac death in patients after a myocardial infarction. Patients with chronic ischemic cardiomyopathy, a long history of heart failure, and an ejection fraction of 0.30 benefit from preventive device therapy and are thus candidates for prophylactic defibrillator implantation. For this purpose, a single-chamber device appears to be appropriate, since there have been no prospective studies showing convincing clinical benefit by adding an atrial lead. For similar patients who have additional intraventricular conduction delays, a biventricular ICD must be considered. However, this decision must be based on individual considerations until more data from prospective trials become available. Prophylactic ICD therapy should not be used in patients with recent myocardial infarction. There is convincing evidence that ICD benefit in coronary patients accrues after a considerable time having elapsed from the most recent infarct, presumably at least 6 months or perhaps longer.     

Radiofrequency catheter ablation in patients with symptomatic atrial flutter/tachycardia after orthotopic heart transplantation

Atrial arrhythmias are common phenomena after orthotopic heart transplantation.1,2 Atrial tachycardia or flutter originating from the donor heart is well recognized.3,4 Although it has been assumed that the recipient atrial myocardium is electrically isolated from that of the donor atrium by the atrioatrial anastomosis, some reports have demonstrated that clinical arrhythmias can arise from the recipient atrium due to the recipient-donor electrical conduction.5-15 Radiofrequency catheter ablat…     

Robotically enhanced placement of left ventricular epicardial electrodes during implantation of a biventricular implantable cardioverter defibrillator system

Biventricular pacing has gained increasing acceptance in advanced heart failure patients. One major limitation of this therapy is positioning the left ventricular stimulation lead via the coronary sinus. This report demonstrates the feasibility of totally endoscopic direct placement of an epicardial stimulation lead on the left ventricle using the daVinci surgical system.     

Comparison of beta-blockers, amiodarone plus beta-blockers, or sotalol for prevention of shocks from implantable cardioverter defibrillators: the OPTIC Study: a randomized trial

Context  Implantable cardioverter defibrillator (ICD) therapy is effective but is associated with high-voltage shocks that are painful. Objective  To determine whether amiodarone plus -blocker or sotalol are better than -blocker alone for prevention of ICD shocks. Design, Setting, and Patients  A randomized controlled trial with blinded adjudication of events of 412 patients from 39 outpatient ICD clinical centers located in Canada, Germany, United States, England, Sweden, and Austria, conducted from January 13, 2001, to September 28, 2004. Patients were eligible if they had received an ICD within 21 days for inducible or spontaneously occurring ventricular tachycardia or fibrillation. Intervention  Patients were randomized to treatment for 1 year with amiodarone plus -blocker, sotalol alone, or -blocker alone. Main Outcome Measure  Primary outcome was ICD shock for any reason. Results  Shocks occurred in 41 patients (38.5%) assigned to -blocker alone, 26 (24.3%) assigned to sotalol, and 12 (10.3%) assigned to amiodarone plus -blocker. A reduction in the risk of shock was observed with use of either amiodarone plus -blocker or sotalol vs -blocker alone (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.28-0.68; P<.001). Amiodarone plus -blocker significantly reduced the risk of shock compared with -blocker alone (HR, 0.27; 95% CI, 0.14-0.52; P<.001) and sotalol (HR, 0.43; 95% CI, 0.22-0.85; P = .02). There was a trend for sotalol to reduce shocks compared with -blocker alone (HR, 0.61; 95% CI, 0.37-1.01; P = .055). The rates of study drug discontinuation at 1 year were 18.2% for amiodarone, 23.5% for sotalol, and 5.3% for -blocker alone. Adverse pulmonary and thyroid events and symptomatic bradycardia were more common among patients randomized to amiodarone. Conclusions  Despite use of advanced ICD technology and treatment with a -blocker, shocks occur commonly in the first year after ICD implant. Amiodarone plus -blocker is effective for preventing these shocks and is more effective than sotalol but has an increased risk of drug-related adverse effects. Clinical Trials Registration  ClinicalTrials.gov Identifier: NCT00257959      

Das Brugada-Syndrom, seltene Differentialdiagnose der Synkope

Hintergrund:  

Das Brugada-Syndrom, als autosomal-dominante Erbkrankheit, ist eine primäre elektrische Störung ohne erkennbare strukturelle Herzerkrankung, die mit lebensgefährlichen ventrikulären Rhythmusstörungen assoziiert ist. Der bislang einzig nachgewiesene Gendefekt liegt auf dem SCN5A-Gen, welches die α-Untereinheit des humanen kardialen Natriumkanals kodiert.     

Pharmakologische Therapie von Vorhofflimmern und Vorhofflattern

Hintergrund: Trotz der zunehmenden Anwendung invasiv elektrophysiologischer Behandlungsverfahren von Vorhofflimmern und Vorhofflattern bleibt die pharmakologische Frequenz- oder Rhythmusstabilisierung auch heute für über 90% aller betroffenen Patienten die Therapie der ersten Wahl. Methode: Literaturübersicht über relevante Studien zur differenzierten Pharmakotherapie von Vorhofflimmern bzw. -flattern mittels Frequenzkontrolle oder Kardioversion und Erhalt von Sinusrhythmus einschließlich der aktuellen diesbezüglichen Richtlinien. Ergebnisse: Nach der gegenwärtigen Datenlage zeigen sich unter Rhythmus- und alleiniger Frequenzkontrolle vergleichbare Ansprechraten bezüglich einer symptomatischen Verbesserung. Detaillierte Daten großer randomisierter Studien hierzu werden in Kürze auch Aussagen über die Prognose unter den verschiedenen Behandlungsstrategien ergeben und weitere Subanalysen für unterschiedliche Patientenkollektive zulassen. Derzeit hat die externe elektrische Kardioversion unter Anwendung der biphasischen Stromabgabe eine Erfolgsrate von über 90%. Im Gegensatz hierzu ist die pharmakologische Rhythmisierung mit einem geringeren Akuterfolg sowie mit potentiell vital bedrohlichen Komplikationen behaftet, weshalb in den meisten Fällen bereits zur Einleitung einer solchen Therapie eine Hospitalisierung erforderlich ist. Die bekannten Nebenwirkungen der Klasse-I-Antiarrhythmika begrenzen ihre Anwendung in der Kardioversion sowie zum Erhalt des Sinusrhythmus überwiegend auf Patienten ohne strukturelle Herzerkrankung. Auch die ersten klinischen Studien mit neuen, sogenannten "reine Klasse-III-Antiarrhythmika", welche eine ausgeprägte Repolarisationsverlängerung bewirken, zeigen als limitierende Nebenwirkung eine signifikante Inzidenz der Torsade-de-Pointes-Kammertachykardie. Aufgrund der erwiesenen prognostischen Vorteile der Betablocker besteht für diese Substanzen bereits eine primäre Indikation bei häufig zugrunde liegender kardiovaskulärer Erkrankung, so z. B. bei Hypertonie, kompensierter Herzinsuffizienz oder koronarer Herzkrankheit. Die Betablocker weisen nur geringe spezifisch antiarrhythmische Effekte auf, daher ist bei dieser Therapie mit einer eingeschränkten Erfolgsrate zum Erhalt des Sinusrhythmus zu rechnen, direkte Vergleiche mit spezifischen Antiarrhythmika stehen derzeit noch aus. Das kardiale Sicherheitsprofil von Amiodaron sowie die in prospektiven Studien erwiesene Überlegenheit gegenüber allen anderen derzeitig verfügbaren Antiarrhythmika in der Rezidivprophylaxe lassen bei Patienten mit struktureller Herzerkrankung, bei welchen ein längerfristiger Erhalt von Sinusrhythmus klinisch angestrebt wird, einen Ersatz als primäre Therapie angeraten scheinen. Die spezielle Pharmakotherapie bei Vorhofflimmern kann für betroffene Patienten jedoch stets nur individuell und als mögliche Stufentherapie - primär orientiert an der zugrunde liegenden Herzerkrankung und unter wiederholter Abwägung der Therapiestrategien - sowie unter Einbeziehung nichtpharmakologischer Alternativen festgelegt werden. Background: Despite the increasing availability of non-pharmacological treatment options for atrial fibrillation, drug therapy targeted at restoration and maintenance of sinus rhythm, or aimed at symptomatic ventricular rate control remains the mainstay of therapy for the majority of patients. Method: Available data suggest that these two treatment approaches yield similar responder rates with regard to symptomatic improvement. Results: Detailed results from major prospective studies investigating the prognostic effects of different atrial fibrillation treatment modalities are expected to become available soon. At present, however, the coice of the primary treatment strategy, i.e. rate control or rhythm control, still remains upon the clinical decision and expertise of the treating physician. Cardioversion by means of external biphasic shock delivery has shown to effectively convert atrial fibrillation to sinus rhythm in more than 90% of patients. Pharmacological cardioversion, in contrast, has a far lower success rate and may be followed by severe complications mandating in-hospital administration with the majority of drug regimens. For the maintenance of sinus rhythm, the proarrhythmic side effects of Class I antiarrhythmic drugs currently limit their use to those patients without any structural heart disease. Clinical investigation of newer "pure" Class III drugs have shown to excite considerable prolongation of ventricular repolarization duration resulting in a significant risk for torsade-de pointes tachycardia. Betablockers are beneficial in many clinical situations associated with the occurrence of atrial fibrillation, such as heart failure, arterial hypertension and coronary artery disease. These substances, however, do not seem to improve cardioversion rates and their effect in maintaining sinus rhythm is only moderate. Patients with structural heart disease in whom maintenance of sinus rhythm is strongly desired, therefore, are left to amiodarone therapy. The cardiac safety profile as well as the proven effectiveness are unsurpassed by any other available drug at present. This paper reviews major studies published during the last decade implementing recent guidelines regarding pharmacological rate ontrol, cardioversion and maintenance of sinus rhythm and the approach towards patients suffering from paroxysmal atrial fibrillation.