Different Impact of Resting Heart Rate on Adverse Events in Paroxysmal and Sustained Atrial Fibrillation ― The Fushimi AF Registry ―

BACKGROUND: Heart rate (HR) is an important factor in atrial fibrillation (AF); however, it remains unclear whether the impact of HR differs between paroxysmal AF and sustained (persistent and permanent) AF. METHODS AND RESULTS: The association of resting HR during AF with adverse events (composite of all-cause death, hospitalization for heart failure, stroke/systemic embolisms, myocardial infarction, and arrhythmic events) in 1,064 paroxysmal and 1,610 sustained AF patients from the Fushimi AF Registry were investigated. These patients were divided into 4 groups based on their resting HR; ≥110 beats/min (bpm), 80-109 bpm, 60-79 bpm, and <60 bpm. The number of patients in each group was 486, 400, 172, and 22 for paroxysmal AF, and 205, 734, 645, and 71 for sustained AF, respectively. Among patients with sustained AF, a HR ≥110 bpm was associated with a higher incidence of adverse events at 1 year and during the entire follow up (median of 1,833 days) (hazard ratio [95% confidence interval] compared with a HR of 60-79 bpm: 1.90 [1.31-2.72] at 1 year, 1.38 [1.10-1.72] during the entire follow up). Patients with a HR <60 bpm showed higher incidence of adverse events at 1 year; however, the incidence of adverse events did not differ among all HR groups of paroxysmal AF. CONCLUSIONS: Baseline HR was associated with adverse events in sustained AF, but not in paroxysmal AF.