Confounding factors in rate versus rhythm control trials in patients with atrial fibrillation: lessons from the strategies of treatment of atrial fibrillation (STAF) pilot study.

BACKGROUND: The Strategies of Treatment of Atrial Fibrillation (STAF) multicenter pilot trial was one of five completed clinical studies to compare two treatment strategies in patients with atrial fibrillation: the strategy of rhythm control (restoration and maintenance of sinus rhythm) and the strategy of rate control (pharmacologic or invasive rate control and anticoagulation).

METHODS: In STAF 200 patients (100 per group) with persistent atrial fibrillation were randomized to rhythm or rate control. The combined primary endpoint was a combination of death, cardiopulmonary resuscitation, cerebrovascular event, and systemic embolism.

RESULTS: After 19.6 +/- 8.9 (0-36) months there was no difference in the primary endpoint between rhythm control (9/100; 5.54%/year) and rate control (10/100; 6.09%/year; p = 0.99). The percentage of patients in sinus rhythm in the rhythm control group after up to four cardioversions during the follow-up period was 23% at 36 months compared to 0% in the rate control group. Eighteen primary endpoints occurred in atrial fibrillation, only 1 occurred in sinus rhythm (p = 0.049).

CONCLUSIONS: The STAF pilot trial did not show any differences between the two treatment strategies in common with other trials of rhythm versus rate control. These data suggest that there is no benefit in attempting rhythm control in this group of patients with a high risk of arrhythmia recurrence. It remains unclear whether the results in the group of rhythm control would have been better if sinus rhythm had been maintained in a higher proportion of patients since all but one endpoint occurred during atrial fibrillation.