Resting heart rate and incident atrial fibrillation in patients with diastolic dysfunction

Diastolic dysfunction (DD) is associated with incident atrial fibrillation (AF). The influence of resting heart rate (RHR) on incident AF in patients with DD has not been investigated. The goal of this study is to assess the influence of RHR on incident AF in patients with DD. Patients from a large health system with no prior history of AF, a left ventricular ejection fraction ≥50% and documented DD on echocardiography were divided into quartiles (<66, 66-76, 77-91, >91 bpm) based on RHR. Incident AF was estimated using AF hospitalization during follow-up. Hazard ratios (HR) for AF hospitalization and all-cause death were calculated with a Cox proportional hazards model. A total of 19,046 patients were analyzed. Over a median follow-up of 42.2 months, 742 (3.9%) patients were hospitalized for AF. Both slower and faster RHR were associated with increased risk of AF hospitalization (HR 1.40, CI: 1.14-1.71, p = 0.001, HR 1.23, CI: 0.99-1.53, p = 0.06 and HR 1.72, CI: 1.38-2.14, p<0.001, for quartiles 1, 2, and 4, respectively), suggesting a J-shaped relationship. Progressive increase in all-cause death was noted with faster RHR (HR1.19 per quartile increase, CI: 1.16-1.22, p<0.001). These results persisted after adjustment for age, cardiovascular comorbidities, grade of DD and beta blocker use. In conclusion, this large, real-world analysis indicates increased risk of incident AF with slower and faster RHR in patients with DD. Randomized trials are needed to evaluate the potential of RHR modification to mitigate the risk of incident AF.