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.