Purpose:
Previous reports suggested that lenient rate control was not inferior to strict rate control among patients with chronic atrial fibrillation (AF). However, the impact of heart rate (HR) on the incidence of cardiovascular events is not clearly understood.
Methods:
The Fushimi AF Registry, a community-based prospective survey, was designed to enroll all of the AF patients in Fushimi-ku, Kyoto, Japan. At present, follow-up data were available in 3,514 patients (median follow-up period, 842 days). 1,622 patients had chronic AF, and we obtained ECG findings in 1,561 patients. We divided these patients into three groups based on their heart rate; high-HR (HR≥110) (n=179), intermediate-HR (80≤HR<110) (n=695), and low-HR (HR<80) (n=687), and explored the cardiovascular events (composite of cardiovascular death, hospitalization for heart failure, and arrhythmic events).
Results:
Mean HR was 128±13 bpm, 93±8 bpm, and 67±9 bpm, respectively. High HR group was younger than other groups, but the prevalence of heart failure was the highest (44.7%, 37.0%, 32.3%; p=0.007) and left-ventricular ejection fraction was the lowest (56.5±14.6%, 60.7±11.9%, 62.7±10.5%; p<0.0001). Prescription of beta-blocker (37.4%, 28.9%, 30.0%) and diltiazem (2.8%, 2.9%, 4.2%) was comparable, but prescription of verapamil was the highest in high-HR group (19.0%, 12.4%, 8.0%; p=0.0001), and prescription of digitalis was the highest in low-HR group (14.0%, 18.2%, 23.4%; p=0.005). Mean CHADS2 score was 2.3±1.3, 2.2±1.3, and 2.2±1.4, respectively. In Kaplan-Meier analysis, the incidence of cardiovascular events was higher in high-HR groups than intermediate- and low-HR group (9.2%/year vs 5.8%/year, p=0.02), but was similar between intermediate- and low-HR group (6.2%/year vs 5.4%/year, p=0.3). The incidence of stroke or systemic embolism was comparable between the three groups (2.6%/year, 3.6%/year, 2.4%/year). Cox proportional hazard ratios [95%CI] of high- and intermediate-HR for cardiovascular events compared to low-HR were 1.63 [1.06-2.44] and 1.10 [0.81-1.79], respectively.
Conclusions:
Among chronic AF patients, the incidence of cardiovascular events was higher in the patients with high-HR, but was similar between intermediate- and low-HR groups.
Effects of metoprolol on heart rate in patients with digitalis treated chronic atrial fibrillation