Phase response of the spectral coherence function between heart rate variability and ventricular repolarization duration in normal subjects

Ventricular repolarization duration (VRD) represents the time for the ventricular myocardium to recover excitability after depolarization. VRD presents variability that is modulated by the instantaneous heart rate (HR) and autonomic activity, which promotes the HR variability (HRV). This study was conducted to evaluate the phase response and the amplitude of the coherence function between the VRD and the HR in normal subjects. The authors conclude that the mechanisms of control of the VRD in the resting condition sustain a memory effect of remote RR interval in LF and an anticipating response in the HF range of the power spectrum, which seems to be related with a direct effect on cardiac fibers.