Discharge heart rate and 1-year clinical outcomes in heart failure patients with atrial fibrillation

Background: The association between heart rate and 1-year clinical outcomes in heart failure (HF) patients with atrial fibrillation (AF), and whether this association depends on left ventricular ejection fraction (LVEF), are unclear. We investigated the relationship between discharge heart rate and 1-year clinical outcomes after discharge among hospitalized HF patients with AF, and further explored this association that differ by LVEF level. Methods: In this analysis, we enrolled 1760 hospitalized HF patients with AF from the China Patient-centered Evaluative Assessment of Cardiac Events Prospective Heart Failure study from August 2016 to May 2018. Patients were categorized into three groups with low (<65 beats per minute [bpm]), moderate (65-85 bpm), and high (>= 86 bpm) heart rate measured at discharge. Cox proportional hazard models were employed to explore the association between heart rate and 1-year primary outcome, which was defined as a composite outcome of all-cause death and HF rehospitalization. Results: Among 1760 patients, 723 (41.1%) were women, the median age was 69 (interquartile range [IQR]: 60-77) years, median discharge heart rate was 75 (IQR: 69-84) bpm, and 934 (53.1%) had an LVEF <50%. During 1-year follow-up, a total of 792 (45.0%) individuals died or had at least one HF hospitalization. After adjusting for demographic characteristics, smoking status, medical history, anthropometric characteristics, and medications used at discharge, the groups with low (hazard ratio [HR]: 1.32, 95% confidence interval [CI]: 1.05-1.68, P = 0.020) and high (HR: 1.34, 95% CI: 1.07-1.67, P = 0.009) heart rate were associated with a higher risk of 1-year primary outcome compared with the moderate group. A significant interaction between discharge heart rate and LVEF for the primary outcome was observed (P for interaction was 0.045). Among the patients with LVEF >= 50%, only those with high heart rate were associated with a higher risk of primary outcome compared with the group with moderate heart rate (HR: 1.38, 95% CI: 1.01-1.89, P = 0.046), whereas there was no difference between the groups with low and moderate heart rate. Among the patients with LVEF <50%, only those with low heart rate were associated with a higher risk of primary outcome compared with the group with moderate heart rate (HR: 1.46, 95% CI: 1.09-1.96, P = 0.012), whereas there was no difference between the groups with high and moderate heart rate. Conclusions: Among the overall HF patients with AF, both low (<65 bpm) and high (>= 86 bpm) heart rates were associated with poorer outcomes as compared with moderate (65-85 bpm) heart rate. Among patients with LVEF >= 50%, only a high heart rate was associated with higher risk; while among those with LVEF <50%, only a low heart rate was associated with higher risk as compared with the group with moderate heart rate. Trail Registration: Clinicaltrials.gov; NCT02878811.