Maintenance of sinus rhythm with metoprolol CR initiated before cardioversion and repeated cardioversion of atrial fibrillation: a randomized double-blind placebo-controlled study.

AIMS: To assess the effect of metoprolol in combination with repeated cardioversion on maintenance of sinus rhythm (SR). METHODS AND RESULTS: Consecutive outpatients with persistent atrial fibrillation (AF) were randomized to treatment with metoprolol CR or placebo in a double-blind fashion. Study treatment was started at least one week before direct current (DC) cardioversion. Patients were followed once a week during the first 6 weeks after cardioversion. In case of relapse during this period, a second cardioversion was performed. Total treatment time was 6 months. A total of 168 patients were randomized to metoprolol (n = 83) or placebo (n = 85). The dose of study treatment at cardioversion was 169 +/- 47 mg in the metoprolol group and 180 +/- 40 mg in the placebo group (P = 0.12). In an intention-to-treat analysis, 46 patients (55%) in the metoprolol group and 34 patients (40%) in the placebo group (P = 0.04) had SR 1 week after cardioversion, and 38 patients (46%) in the metoprolol group compared with 22 patients (26%) in the placebo group had SR after 6 months (P < 0.01). CONCLUSION: A treatment strategy of metoprolol CR started before cardioversion in combination with prompt second cardioversion in case of early relapse (1-6 weeks) significantly increases the proportion of patients in SR during six months of follow-up.

Self-limited bursts of atrial fibrillation following successful cardioversion.

BACKGROUND: To evaluate if self-limited episodes of atrial fibrillation after DC cardioversion predict recurrence of persistent atrial fibrillation. To evaluate the incidence and duration of such episodes as well as their change over time. METHODS: Consecutive patients with persistent atrial fibrillation, scheduled for direct current cardioversion were prospectively included in the study. Ambulatory ECG Holter monitoring (24 h) was performed one, three and 6 weeks after successful cardioversion. RESULTS: A total of 84 patients were prospectively included in the study. Sinus rhythm was restored in 74 patients (88%). At 6 weeks of follow-up 40 patients out of 74 (54%) had sinus rhythm, and 34 patients (46%) had relapsed into persistent atrial fibrillation. Eight out of these 34 patients (24%) had bursts of atrial fibrillation at their first Holter recording, compared to 12 patients out of 40 (30%) in sinus rhythm at 6 weeks (p>0.05). On the first, second and third Holter recording 21 patients out of 51 (41%), 21 patients out of 43 (49%) and 15 out of 40 patients (38%) had self-limited bursts of atrial fibrillation, respectively. The incidence or duration of episodes did not vary over time during the 6 weeks of follow-up. CONCLUSION: In patients successfully converted to sinus rhythm self-limited bursts of atrial fibrillation do not predict recurrence of persistent atrial fibrillation during 6 weeks of follow up. Brief self-limited episodes of atrial fibrillation are common, and the incidence and duration of such episodes are constant during a 6 weeks period after DC cardioversion.