Physiological Rate Adaptation with an Elevated Basic Rate for Prevention of Paroxysmal Atrial Tachyarrhythmia

摘要: Atrial overdrive pacing may suppress atrial extrasystoles and thus prevent the onset of atrial fibrillation (AF). However, after restoration of the sinus rhythm the atrium is the most vulnerable to reinitiation of AF. The aim of our study was to evaluate the efficacy of rate-adaptive pacing based on myocardial contractility (DDD-CLS), used in combination with an elevated basic rate, in diminishing AF in patients with bradytachycardia syndrome. Twentysix patients with a mean age of 59±10 years (57% male, 65% presenting with Chagas disease) were enrolled in a prospective study. Each patient was taking amiodarone (400 mg/day) during the study. Two months after implantation the patients were randomized to receive either DDD pacing at a basic rate of 60 bpm or DDD-CLS pacing with a basic rate set to 80 bpm. The Mode switching option was activated in all patients and pacemaker statistics were used to count the number of mode switch episodes. A 3-channel, 24-hour Holter ECG was obtained in all patients. The mode crossover was performed after 3 months. Holter ECG recordings revealed a significant reduction in the number of atrial extrasystoles (p< 0.01) and the number of ventricular complexes during AF (p< 0.05) in the DDD-CLS pacing with an elevated basic rate. The number of mode switch episodes recorded in the pacemaker memory over 3 months was also reduced during DDD-CLS pacing with an elevated basic rate (p< 0.001). In conclusion, myocardial contractility-based, rate-adaptive pacing with a basic rate of 80 bpm reduced the incidence of paroxysmal AF.