[Relations between ventricular extrasystole, time of day and heart rate]

42 patients with complex ventricular arrhythmias were subjected to continuous long-term ECGs for three 24-hour periods. In 21 patients, the occurrence and frequency of simple ventricular premature beats (VPB) did not depend on whether it was day or night. The other 21 patients showed a regular reproducible day-and-night rhythm during all three registration periods. 14 (33%) of them had the highest VPB-frequency during day and 7 (17%) at night.--16 patients showed paired VPB. Again, only 50% (8 patients) showed a regular reproducible day-and-night rhythm during all three registration periods. 6 of them had the highest frequency of paired VPB during day and 2 at night. 23 patients showed a clearly recognizable relationship between VPB-frequency and heart rate during all three periods. In 18, the VPB-frequency ran parallel to the heart rate, but in 5 patients the VPB-frequency ran contrary to the heart rate. In 16 patients, the VPB-frequency showed a constant relationship to both heart rate and time of day, 5 patients only evidenced a relationship to time of day and 7 only to heart rate. The distinct dependence of VPB-frequency upon heart rate and/or time of day in numerous patients could be of differential therapeutic significance.