Asymmetry of the Variability of Heart Rate and Conduction Time Between Atria and Ventricles

Abstract

Background: Heart rate asymmetry is caused by an unequal contribution of heart rate decelerations and accelerations to heart rate variability. This study evaluates the asymmetric properties of the variability of the AA, HH, VV, AH and HV intervals. Methods and Results: We recorded 50 1-min intracardiac ECG tracings from 10 patients (18–66 years old; 8 females) during a routine electrophysiological study. Standard descriptors of variance asymmetry were calculated for all intervals. Nonparametric tests were used for statistical comparisons. The prolongations of VV (P=0.0297), AH (P=0.0133) and HV (P=0.0004) intervals contributed significantly more than their shortenings to their short-term variance. The proportion of recordings with a larger contribution of prolongations than shortenings was significantly different from random for VV (0.66, P=0.0328), AH (0.68, P=0.0154) HV (0.74, P=0.0009). Conclusions: In addition to heart rate asymmetry (VV interval), the conduction from the atria, through the atrioventricular node, His-Purkinje system to ventricles shows asymmetric properties in 1-min tracings.  (Circ J 2013; 77: 2904–2911)