Heart rate control is the primary therapy for atrial fibrillation. While guidelines recommend strict control, evidence supporting this approach is scarce. Van Gelder and colleagues sought to determine whether lenient control of heart rate is as effective as strict control in treating atrial fibrillation.

The researchers enrolled 614 participants, ages 80 years and younger, who'd had atrial fibrillation for up to 12 months, had a mean resting heart rate above 80 beats per minute, and were taking aspirin or an oral anticoagulant. The lenient (n = 311) and strict (n = 303) control groups were similar except more patients in the lenient group had coronary artery disease and more were taking statins. Patients in the lenient group also had a slightly higher diastolic blood pressure than those in the strict group (85 mmHg versus 83 mmHg, respectively).

Patients received one or more negative dromotropic medications to reduce their resting heart rate to the target rates of below 110 beats per minute in the lenient control group and below 80 beats per minute (below 110 during exercise) in the strict control group. After dose adjustments to reach these rates, the lenient group's average resting heart rate was 93 beats per minute and the strict group's was 76 beats per minute. At the end of the up to three-year follow-up period, mean resting heart rate was 85 and 76 beats per minute in the lenient and strict groups, respectively. More patients in the lenient group than in the strict group met the heart rate targets (97.7% versus 67%) and with fewer total visits (75 versus 684).

The primary outcome (a composite of cardiovascular-related death, hospitalization for heart failure, stroke, systemic embolism, major bleeding, and arrhythmic events) was reached by 38 patients in the lenient group and 43 in the strict group. A comparable percentage of patients in the lenient and strict groups died (5.6% and 6.6%, respectively). Similarly, 45.6% of those in the lenient group compared with 46% in the strict group experienced atrial fibrillation symptoms.

Thus, lenient control of heart rate in the treatment of atrial fibrillation is as effective as strict control but offers the benefit of being more convenient and requiring fewer patient visits to achieve.