Atrial therapies reduce atrial arrhythmia burden in defibrillator patients

Background-Approximately 25% of patients who receive an implantable cardiov erter-defibrillator (ICD) to treat ventricular tachyarrhythmias have docume nted atrial tachyarrhythmias before implantation. This study assessed the a bility of device-based prevention and termination therapies to reduce the b urden of spontaneous atrial tachyarrhythmias. Methods and Results-Patients with a standard indication for the implantatio n of an ICD and 2 episodes of atrial tachyarrhythmias in the preceding year received a dual-chamber ICD (Medtronic 7250 Jewel AF) that uses pacing and shock therapies for prevention and/or termination of atrial tachyarrhythmi as. In a multicenter trial, patients were randomized to 3-month periods wit h atrial therapies "on" or "off" and subsequently crossed over. Analysis wa s performed on the 52 of 269 patients who had episodes of atrial tachyarrhy thmia and had greater than or equal to 30 days of follow-up with atrial the rapies on and off. The atrial therapies resulted in a reduction of atrial t achyarrhythmia burden from a mean of 58.5 to 7.8 h/mo. A paired analysis (W ilcoxon signed-rank test) showed that the median difference in burden (I. I h/mo) was highly significant (P = 0.007). When the subgroup of 41 patients treated only with atrial pacing therapies was analyzed, the reduction in b urden persisted (P = 0.01). Conclusions-In this study, patients with a standard ICD indication and atri al tachyarrhythmias had a significant reduction in atrial tachyarrhythmia b urden with use of atrial pacing and shock therapies.