Lenient versus Strict Rate Control in Patients with Atrial Fibrillation

TLDR

Rate control is the usual therapy for atrial fibrillation, yet guidelines favor strict control without solid evidence. The study tested whether lenient rate control is non‑inferior to strict control for preventing cardiovascular morbidity and mortality in patients with permanent atrial fibrillation. The authors randomized 614 permanent atrial fibrillation patients to a lenient strategy (resting heart rate < 110 bpm) or a strict strategy (resting heart rate < 80 bpm and heart rate during moderate exercise < 110 bpm). Over a median 2‑3 year follow‑up, the primary composite outcome occurred in 12.9 % of lenient versus 14.9 % of strict patients, demonstrating non‑inferiority, and individual component rates, symptoms, and adverse events were similar, while lenient control achieved higher target rates with fewer visits. ClinicalTrials.gov.

Abstract

Rate control is often the therapy of choice for atrial fibrillation. Guidelines recommend strict rate control, but this is not based on clinical evidence. We hypothesized that lenient rate control is not inferior to strict rate control for preventing cardiovascular morbidity and mortality in patients with permanent atrial fibrillation.We randomly assigned 614 patients with permanent atrial fibrillation to undergo a lenient rate-control strategy (resting heart rate <110 beats per minute) or a strict rate-control strategy (resting heart rate <80 beats per minute and heart rate during moderate exercise <110 beats per minute). The primary outcome was a composite of death from cardiovascular causes, hospitalization for heart failure, and stroke, systemic embolism, bleeding, and life-threatening arrhythmic events. The duration of follow-up was at least 2 years, with a maximum of 3 years.The estimated cumulative incidence of the primary outcome at 3 years was 12.9% in the lenient-control group and 14.9% in the strict-control group, with an absolute difference with respect to the lenient-control group of -2.0 percentage points (90% confidence interval, -7.6 to 3.5; P<0.001 for the prespecified noninferiority margin). The frequencies of the components of the primary outcome were similar in the two groups. More patients in the lenient-control group met the heart-rate target or targets (304 [97.7%], vs. 203 [67.0%] in the strict-control group; P<0.001) with fewer total visits (75 [median, 0], vs. 684 [median, 2]; P<0.001). The frequencies of symptoms and adverse events were similar in the two groups.In patients with permanent atrial fibrillation, lenient rate control is as effective as strict rate control and is easier to achieve. (ClinicalTrials.gov number, NCT00392613.)