RELATION OF CIRCADIAN VENTRICULAR ECTOPIC ACTIVITY TO CARDIAC MORTALITY

The relation between the circadian occurrence of ventricular premature depolarizations (VPD) and sudden arrhythmic death was examined in a s ubset of patients entered into the Cardiac Arrhythmia Suppression Tria l (CAST), Ambulatory electrocardiographic recordings with hourly measu rement of VPD frequency were available in 357 patients, Forty percent of the patients (142 of 357) demonstrated circadian variation in VPD f requency between 6:00 n.M. and 9:59 A.M. that was significantly higher (p < 0.05) than what could randomly be expected from an overall 24-ho ur average for that patient. The only baseline characteristics in pati ents with circadian VPDs were age (p < 0.04), history of cardiac arres t (p < 0.01), presence of higher frequency of VPDs (p < 0.002), more f requent episodes of ventricular tachycardia (p < 0.04), and more frequ ent episodes of slow runs (p < 0.04), There was no difference in morta lity in patients with or without circadian VPD variation; drug treatme nt did not effect mortality, These data indicate that the presence of circadian VPDs is not a predictor of sudden arrhythmic death in patien ts with a high frequency of VPDs.