Resting heart rate assessed within clinical practice demonstrates no prognostic relevance for defibrillator recipients in the German DEVICE registry

Resting heart rate (RHR) has prognostic implications in heart failure with reduced ejection fraction, where ≤ 70 bpm is targeted. Whether a RHR > 70 bpm assessed within clinical practice goes along with elevated cardiovascular risk in implantable cardioverter-defibrillator (ICD) / cardiac resynchronization therapy-defibrillator (CRT-D) recipients remains incompletely understood. A total of 1589 patients (ICD n = 1172 / CRT-D n = 417, median age 65 years, 22.6% female) undergoing ICD/CRT-D implantation or revision in the prospective German DEVICE multicenter registry were analyzed. RHR was assessed via a 12-channel electrocardiogram at enrollment. 1-year outcomes (all-cause mortality, major cardio- and cerebrovascular events (MACCE), all-cause hospital admission) were compared between patients with a RHR ≤ 70 bpm and > 70 bpm. 733 patients (46.1%) showed a RHR > 70 bpm. Median RHR was 63 (interquartile range 59; 68) bpm (≤ 70 bpm group) and 80 (75; 89) bpm (> 70 bpm group). Heart failure with reduced ejection fraction was present in 76.3%, a prior myocardial infarction in 32.4% and non-ischemic heart disease in 44.9%. One-year all-cause mortality was similar between RHR groups (≤ 70 bpm 5.4% vs. > 70 bpm 5.4%, p = 0.96), and subgroup analysis regarding patient characteristics and comorbidities revealed only a significantly higher rate of patients with dual chamber ICD in the > 70 bpm group (0.8% vs. 9.2%, p = 0.003). MACCE (5.9% vs. 6.1%, p = 0.87) and defibrillator shock rates (9.9% vs. 9.8%, p = 1.0) were similar. Higher all-cause hospital admission rates were observed in patients with > 70 bpm RHR (23.1% vs. 29.0%, p = 0.027) driven by non-cardiovascular events (6.0% vs. 11.7%, p = 0.001). In conclusion, in ICD and CRT-D recipients a RHR at admission > 70 bpm may indicate patients at increased risk of all-cause hospital admission but not of other adverse cardiovascular events or death at 1-year follow-up.