Effect of Atrial Tachyarrhythmia Duration on Percentage of Time with Atrial Pacing in Pacemaker Patients with Paroxysmal Atrial Fibrillation

Atrial pacing can prevent the recurrence of paroxysmal atrial tachyarrhythmia (AT) in pacemaker patients. The aim of the study was to determine in pacemaker patients the effect of AT duration on the percentage of time with atrial pacing by programming the same setting twice. METHODS: In 14 pacemaker patients with paroxysmal AT the dual-chamber pacemaker was programmed to identical parameters for two consecutive follow-up periods. The pacemakers were interrogated after three months to determine the percentage of time with atrial pacing relative to the total time of follow-up periods and the AT duration (atrial rates >150 bpm). The two three-month follow-up periods were compared to each other. The differences between the two follow-up periods were determined for the percentage of time with atrial pacing as well as for the AT duration. To assess the relationship between atrial pacing and AT duration, the differences between the two follow-up periods for atrial pacing and AT duration were correlated to each other. In addition, the percentage of atrial pacing was corrected for AT duration. RESULTS: Median percentage of atrial pacing relative to the complete follow-up period was 73% after the first and 76% after the second period and median AT duration 21% and 18%, respectively (not significantly different). The differences between the first and second study period were 1% for atrial pacing and -2% for AT duration. The percentage of atrial pacing and AT duration were inversely related together with a significant correlation coefficient of r = 0.95 ( p = 0.0001). After atrial pacing was corrected for AT duration, the percentage of atrial pacing relative to the time in sinus rhythm was significantly higher with a median of 93% for the first and second period ( p = 0.005). The correlation coefficient between the percentage of atrial pacing relative to the time in sinus rhythm and AT duration was r = 0.08 (not significant). CONCLUSIONS: The percentage of time with atrial pacing can be underestimated in patients with paroxysmal atrial fibrillation and should be carefully interpreted in relation to AT duration.