Association between resting heart rate and clinical outcomes in heart failure with preserved ejection fraction: age stratified insights from the KUNIUMI Registry.

Resting heart rate (HR) is a modifiable prognostic marker in heart failure (HF) with reduced ejection fraction, but its relevance in HF with preserved ejection fraction (HFpEF), especially among the very elderly, remains unclear. We aimed to evaluate the prognostic impact of elevated resting HR in HFpEF patients aged 80 years or older and compare it with those younger than 80 years. We prospectively studied 1,109 HFpEF patients from a total of 1,646 consecutive HF patients in the KUNIUMI Registry chronic cohort. Elevated HR was defined as resting HR of 70 beats per minute or more. The primary endpoint was a composite of cardiovascular death and HF hospitalization over a mean follow up of 1.77 ± 0.53 years. Among HFpEF patients in sinus rhythm (SR) aged below 80 years, HR of 70 beats per minute or more was significantly associated with worse cardiovascular outcomes (log rank P < 0.01). However, this association was attenuated in those aged 80 years or older in SR (log rank P = 0.11), and in patients with atrial fibrillation (AF), regardless of age. Elevated HR was independently associated with adverse outcomes in patients aged below 80 years in SR but not in those aged 80 years or older in SR. In conclusion, elevated resting HR is associated with adverse cardiovascular outcomes in HFpEF patients aged below 80 years in SR, but not in those aged 80 years or older or in those with AF. Age and rhythm specific approaches may be warranted in HFpEF management.