Repolarization duration variability: a tool to quantify the autonomic balance at the ventricle

In order to gain insight into the process of cardiac repolarization, the authors defined and studied the repolarization duration variability (RDV) on electrocardiograms. Spectrum techniques were used to evaluate the influence of the autonomic nervous system in the control of repolarization duration (RD). Coherence analysis was used to quantify common contributions between RDV and heart rate variability. The latter gave a reference of the sympathovagal balance. It was found that the autonomic nervous system acts tonically and directly to control RD. This action is mediated through both autonomic limbs