The effect of atrial pacing therapies on atrial tachyarrhythmia burden and frequency - Results of a randomized trial in patients with bradycardia and atrial tachyarrhythmias

OBJECTIVES The Atrial Therapy Efficacy and Safety Trial (ATTEST) was a prospective, randomized study to evaluate preventive pacing and antitachycardia pacing (ATP) in patients with symptomatic atrial fibrillation (AF) or atrial tachycardia (AT). BACKGROUND The effect of the combination of atrial prevention and termination algorithms on AT/AF burden and frequency in pacemaker patients is unknown. METHODS A DDDRP pacemaker (AT500, Medtronic Inc., Minneapolis, Minnesota) with three atrial preventive pacing algorithms and two ATP algorithms was implanted in 368 patients. Patients were randomized one-month post-implant to all prevention and ATP therapies ON or OFF and followed for three months. The OFF group had DDDR pacing at a lower programmed rate of 60 ppm. The AT/AF burden and frequency were determined from daily device counters in 324 patients treated according to protocol. RESULTS In 17,018 episodes with stored electrograms, appropriate detection was confirmed in 17,004 (99.9%). The median percentage of atrial pacing was 98% in the ON group versus 75% in the OFF group (p < 0.001). Using device-defined criteria for successful termination, ATP terminated 8,590 (54%) of 15,789 treated episodes. The median AT/AF burden during the three-month study period was 4.2 h/month ON versus 1.1 h/month OFF (p = 0.20). The median AT/AF frequency was 1.3 episodes/month ON versus 1.2 episodes/month OFF (p = 0.65). System-related, complication-free survival at four months was 90.2% (Kaplan-Meier estimate). CONCLUSIONS This DDDRP pacemaker is safe, has accurate AT/AF detection, and provides ATP with 54% efficacy as defined by the device. The atrial prevention and termination therapies combined did not reduce AT/AF burden or frequency in this patient population. (C) 2003 by the American College of Cardiology Foundation.