Sinus Bradycardia and Sinus Pauses Immediately after Electrical Cardioversion of Persistent Atrial FibrillationWhat Do They Mean?

Background To determine the role of sinus bradyarrhythmia (SB) immediately after electrical cardioversion of persistent atrial fibrillation (AF) on the short-term recurrence rate and long-term pacemaker need and all-cause mortality. Methods SB defined as sinus bradycardia (sinus rate <40 bpm for 2 consecutive cycles) and/or sinus pauses (>2 s), were recorded during 5 minutes immediately after successful DC cardioversion in 140 consecutive patients with persistent AF. Results SB was observed during the first minute of SR in 31 patients (22%). Sinus bradycardia was present in 27 patients, sinus pauses in 16 (>3 s in 10) patients, and both in 12 patients. Compared to patients without SB, the mean heart rate during the first minute after cardioversion was lower, 57 +/- 13 versus 63 +/- 11 bpm; P < 0.05, while the mean heart rates during the subsequent 4 minutes were not statistically significantly different. The AF recurrence rates were not significantly different at 1 week (45% vs. 40%), or at 3 months (68% vs. 53%) in patients with or without SB. After a mean follow-up of 86 +/- 6 months the pacemaker implantation rate was 10% versus 11% (NS) and an all-cause mortality of 26 versus 18% (NS). Conclusions SB immediately after electrical cardioversion of persistent AF had no significant impact on the 3-month AF recurrence rate, the long-term need for pacemaker or all-cause mortality.