Does intensity of rate control influence outcome in persistent atrial fibrillation? Data of the RACE study.

Background: Large trials have demonstrated that rate control is an acceptable alternative for rhythm control. However, optimal heart rate during atrial fibrillation (AF) remains unknown. Aim of this analysis was to compare outcome between rate control > or =80 and <80 beat/min in patients with persistent atrial fibrillation.

Methods: In the RAte Control versus Electrical cardioversion for persistent atrial fibrillation study, 522 patients were included, and 256 were randomized to rate control. This post hoc analysis included patients randomized to rate control. Patients were divided according to their mean resting heart rate during follow-up, <80 beat/min (n = 75) or > or =80 beat/min (n = 139). The end point, a composite of cardiovascular mortality, heart failure, thromboembolic complications, bleeding, pacemaker implantation, and severe drug side effects, was compared between both groups.

Results: During follow-up (2.3 +/- 0.6 years), a significant difference between both groups in heart rate was observed (72 +/- 5 vs 90 +/- 8 beat/min; P < .001). Rate control drugs were not significantly different between both groups. New York Heart Association class and fractional shortening remained unchanged in both groups. There were 17 (23%) end points in the low heart rate group and 24 (17%) in the higher heart rate group (absolute difference, 5.4 [-7.3 to 8.2]; P = ns). Independent predictors for the primary end point were coronary artery disease, digoxin use, and interrupted anticoagulation, not high heart rate. Quality of life was comparable in both groups during follow-up.

Conclusions: In patients treated with a rate control strategy, no differences were observed in terms of cardiovascular morbidity, mortality, and quality of life between the observed differences in level of rate control throughout follow-up.