[Cardiac arrhythmias in active elderly persons--age dependence of heart rate and arrhythmias].
Arrhythmias and heart rate of 82 active elderly persons (mean age 79.5 yrs) were registered by 24-hour electrocardiographic recording and compared with the results of 100 asymptomatic subjects (age 34.8 yrs). In each decade 10 men and 10 women were included. Maximal heart rate was lower in old age but over 100 bpm. Minimal and nocturnal heart rates showed a steady rise with increasing age. The mean 24-hour heart rate was higher in middle-aged females than in males, whereas in the elderly no sex-related difference was observed. Sinus arrhythmia, wandering pacemaker, short lengthening of RR-intervals prevailed in younger persons. Short sinus-tachycardias in the late night were equally frequent in both groups. The frequency of supraventricular premature beats did not differ between the two groups (85.4 vs. 76%). However, high intraindividual numbers and more complex forms were more frequent in the elderly. Paroxysmal atrial fibrillation was never registered. Permanent atrial fibrillation occurred in 41% of the subjects being between 90 and 102 years of age. Ventricular arrhythmias were age-related: 87.2% of the elderly vs. 50% of the middle-age subjects had ventricular premature beats, predominantly frequent and complex forms. A significant age relation to bradycardias could not be observed: Sinus pauses over 2000 ms (11 vs. 17%), first and second degree AV-block (22 vs. 21%) occurred equally frequent in both groups. An intermittent short third degree AV-block was observed in a man 84 years old who was asymptomatic. Right bundle branch block was present only in the elderly (6.1%). No arrhythmia-related increase of mortality was observed during a seven-year follow-up.