[Heart rate-ventricular extrasystole relations and their dependence on circadian rhythms].

The linear correlation of the circadian rhythms (CR) of heart rate (HR) with those of ventricular extrasystole (VE) is analyzed by electrocardiographic ambulatory monitoring in 32 patients: 22 with ischemic post-infarction cardiopathy (group A) and ten free of structural cardiopathy (group B). Variability expressed as the coefficient of ventricular extrasystole variation (100 x standard deviation/mean) presented an inverse correlation with the number of recording extrasystoles. Linear correlation between HR and VE was statistically significant in 72% of recordings in group A, and in 60% in group B. The percentage of cases with significant linear correlation was greater on analyzing the three-minute periods than with the longer periods. When the cases analyzed presented over 200 extrasystoles, the percentage with significant linear correlation between HR and extrasystole was greater in group A than in group B. The circadian rhythm of the ventricular extrasystoles using interpolation of a cosinor function was significant in 50% of group A cases, and in 60% of group B. The achrophases were diurnal in group B, but only in 45% of cases in group A, two correspondence models being found between the CR achrophases and the inverse linear correlation between HR and VE.