Temporal changes in resting heart rate before and after heart failure decompensation in a large real-world population of patients with reduced ejection fraction

Abstract

Abstract Background Diagnostic parameters measured in implantable cardioverter defibrillators (ICD) and cardiac resynchronization therapy defibrillators (CRTD) have been shown to change before and after heart failure (HF) events with fluid overload. Purpose We investigated the temporal characteristics of nighttime heart rate, as a surrogate of resting heart rate, before and after HF events in a large real-world cohort of patients with ICD/CRTD devices. Methods We linked a de-identified database of aggregated electronic health record (EHR) data (2007–2017) to a manufacturer's device database with continuous diagnostic monitoring data. Patients with ICD/CRTD implants with HF related diagnostics were included for this study. The device computes nighttime heart rate as the average heart rate between midnight and 4 am. HF event was defined as an inpatient, emergency department, or observation unit stay in a hospital with primary diagnosis of HF and intravenous diuretics administration. Temporal ensemble average of night heart rate in the 60 days pre and post HF events were compared between HF events with and without readmission within 60 days as well as with periods with no HF events. Results A total of 17,886 patients with 1.8±1.2 years of follow-up met inclusion criteria. The average age of patients was 66.6±12.3 years, with 72% being males, and 51% with ICD devices. The average night heart rate pre and post HF events with and without readmission and in follow-ups with no events is shown in Figure. A total of 1174 patients had 1425 HF events with no readmission for HF within 60 days and 282 patients had 295 HF events which were followed by readmission for HF within 60 days. A total of 17,839 patients had no HF events over 86,858 follow-up months. A 3-day average night heart rate increased by >3 bpm in a large proportion of patients in the 30-day period before HF event compared to 30-day periods with no events (28% vs 16%; Odds Ratio: 2.08; p<0.001). Patients who were readmitted for HF have higher average NHR before and after admission compared to patients who are not readmitted. In patients who were not readmitted, the night heart rate recovers to baseline levels on an average within 10 days post discharge. Conclusions In a large real-world population of patients with ICD/CRTD devices, the average night heart rate increases before HF events. Patients who are readmitted are more likely to have higher night heart rate after discharge. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Medtronic Plc