Different spectral components of 24 h heart rate variability are related to different modes of death in chronic heart failure

Aims To assess whether analysis of heart rate variability (HRV) from 24h Holter recordings provides information about the mode of death (pump failure vs. sudden death) in chronic heart failure (CHF). Methods and results We analysed 24h HRV in 330 consecutive CHF patients in sinus rhythm. Indices derived from time domain, spectral domain, and fractal analyses of 24h automatic HRV were evaluated. Data from clinical assessment, echocardiography, right heart catheterization, exercise test, blood biochemical examination, and arrhythmia pattern were analysed. Patients were followed up for 3 years. Two simple multivariable models, both including 24h spectral indices, were able to identify patients at higher risk of progressive pump failure and sudden death, respectively. Depressed power of night-time HRV (≤509ms2) below 0.04Hz very low frequency (VLF), high pulmonary wedge pressure (PWP ≥ 18mmHg) and low left ventricular ejection fraction (LVEF ≤ 24%) were independently related to death for progressive pump failure, while the reduction of power between 0.04 and 0.15Hz at night (LF ≤ 20ms2) and increased left ventricular end-systolic diameter (LVESD ≥ 61mm) were linked to sudden mortality. Conclusion Automatic spectral analysis of 24h HRV provides independent risk indices related to mode of death in sinus rhythm CHF patients.