Rate Control Efficacy in Permanent Atrial Fibrillation: Successful and Failed Strict Rate Control Against a Background of Lenient Rate Control. Data From RACE II (Rate Control Efficacy in Permanent Atrial Fibrillation)
Does the degree of rate control affect outcomes in patients with permanent atrial fibrillation (AF)?
This was a post-hoc analysis of 608 patients with permanent AF randomized to strict rate control (rate <80 bpm at rest and <110 bpm during moderate exercise, n = 301) or lenient rate control (resting rate <110 bpm, n = 307). The strict rate control criteria were met in 203/301 patients. The primary outcome was a composite of cardiovascular morbidity and mortality.
The mean resting heart rate at completion of the dose-adjustment phase was significantly lower in the successful strict control group (72 bpm) than in the failed strict control group (86 bpm) and the lenient control group (93 bpm). During a median follow-up of 2.9 years, there was not a significant difference in the primary outcome between patients with successful strict control (14.2%), failed strict control (15.0%), and lenient rate control (12.15).
Strict heart rate control does not improve outcomes in patients with permanent AF.
The authors concluded that lenient rate control is an appropriate first-line approach in patients with permanent AF. However, the mean resting rate in the lenient control group was close to 90 bpm, leaving open the possibility that outcomes might have been worse in this group if more patients had had a resting heart rate of 100-110 bpm. Regardless, an important caveat is that strict rate control is appropriate in patients who develop a cardiomyopathy in the setting of AF, and in patients who are symptomatic during lenient heart rate control.
Keywords: Follow-Up Studies, Cardiomyopathies, Heart Rate, Catheter Ablation
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