Background: Abnormalities in autonomic control are a feature of neuroendocrine activation in HF and are responsible for dysregulation of biological rhythms. The purpose was to investigate the presence and the prognostic significance of long-period heart rate (HR) rhythms in heart failure (HF) patients.
Methods and results: In the study, 92 HF patients were enrolled (age 53 ± 14 years and left ventricular ejection fraction [LVEF] 37 ± 10%). A rhythmometric analysis was used to assess the HR rhythms in 7-days (7D) Holter recordings. Rhythms properties were quantified by mesor and amplitude, in beats/min and by acrophase, in hours. Cardiac death or HF decompensation were registered. All patients had 24-h rhythm, 61 patients (77%) had 8-h rhythm, and 66 patients (83%) had 7D rhythm. Twelve patients (15%) experienced events. Among rhythm parameters only 7D median amplitude was different between patients with or without events: 1.1 beats/min [0.5-1.5] vs. 2.0 beats/min [0.0-3.9], P=0.049 respectively. After multivariate adjustment, LVEF (per 1%, hazard ratio 0.92, 95% confidence interval (CI) 0.87 to 0.98, P=0.01), N-terminal portion of pro-natriuretic hormone type B (per 100 pg/ml, hazard ratio 1.036, 95% CI 1.005-1.069, P=0.022), and 7D amplitude of the HR ≤1.71 beats/min (hazard ratio 5.4, 95% CI 1.2-34.4, P=0.047) were independent predictors of events.
Conclusions: A 7D HR rhythm is present in most patients with HF, and has prognostic significance.