Circadian rhythms of heart rate and premature ventricular beats in the aged

The chronobiological analysis by means of the cosinor method on the dynamic electrocardiographic tracings of 30 subjects aged over 65 years with no clinical or instrumental signs of heart disease revealed a significant circadian rhythm of heart rate with acrophase in the early afternoon. When compared with a group of 30 young adult subjects, the elderly exhibited only a non-significant reduction of the rhythm amplitude. Elderly patients with heart disease exhibited a similar chronobiological pattern of heart rate. Premature ventricular beats (PVBs) were present in all subjects and occurred mostly during the day. A significant circadian rhythm was present only in elderly heart patients with 30-150 PVBs/h. The circadian distribution of PVBs showed significant interindividual differences with nocturnal acrophase in about one third of the patients. The chronobiological analysis can represent the basis for a more appropriate therapeutic approach to the elderly with PVBs.