Abstract
Background The clinical significance of fibrillatory wave on electrocardiography during atrial fibrillation (AF) is poorly understood. The aim of the current study was to explore the association of fine fibrillatory wave with heart failure (HF) in AF. Methods and Results The current study enrolled 2442 patients with AF whose baseline ECG during AF rhythm was available from a community-based prospective survey, the Fushimi AF Registry. The impact of fine fibrillatory wave, defined as the amplitude of fibrillatory waves <0.1 mV, on the primary composite HF end point (a composite of hospitalization attributable to HF or cardiac death) was examined. Fine fibrillatory wave was observed in 589 patients (24.1%). Patients with fine fibrillatory wave were older, and had a higher prevalence of sustained AF, preexisting HF, and larger left atrial diameter than those with coarse fibrillatory wave. During the median follow-up duration of 5.9 years, the cumulative incidence of the primary composite HF end point was significantly higher in patients with fine fibrillatory wave than in those with coarse fibrillatory wave (5.3% versus 3.6% per patient-year, log-rank P<0.001). The higher risk associated with fine fibrillatory wave was consistent even for individual components of the primary composite HF end point. On multivariable analysis, fine fibrillatory wave became an independent predictor for the primary composite HF end point (hazard ratio, 1.31; 95% CI, 1.07-1.61; P=0.01). Conclusions Compared with coarse fibrillatory wave, fine fibrillatory wave was more prevalent in patients with a larger left atrial diameter or those with sustained AF and was independently associated with a higher risk of HF events. Registration URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000005834.