[Maprotiline and the heart rate]

The increased heart rate is a frequent, seldom clinically significant side-effect of antidepressants. There are different opinions about the Maprotiline influence on the heart rate, either about its very existence or the pathophysiological mechanism of its side-effect. The aim of this study was to test the Maprotiline influence on the heart rate of depressed patients and to compare the results with the results of other studies. The study was carried out in a group of 21 patients with a depressive involutional syndrome treated by fixed daily doses of 150 mg of Maprotiline. The heart rate was estimated in a small sample of examinees using the method of paired observations, as a part of the orthostatic cardiovascular tolerance testing by Schellong's method; this was done before the therapy and twice a week during four week of the application of Maprotiline. The increase in the heart rate in the basal reclining position was noticed in 20 patients. The average value was 16 beats per minute. The increase of the heart rate was not noticed immediately after the application of the first doses but after the latency of 8 days on average. While increasing in the basal reclining position, the orthostatic deviation of the heart rate did not significantly change during the therapy. At the end of the study the orthostatic deviation even showed a negative sign. The reclining of the patients at the end of Schellong's test discovered a frequent occurrence of the prolonged blood pressure return from higher to normal values. The results obtained confirm the thesis that the increased heart rate in the therapy with Maprotiline is due to its noradrenergic activity, in other words, to its ability to block the "reuptake" of noradrenalin in the synaptic cleft. The delay of the heart rate increase in the basal reclining position, a more frequent prolonged blood pressure return in the further phase of the study, and the therapeutic response delay in the treatment of depression are explained by the authors by the same mechanism: by the most probable existence of the pathological changes in the synapses.(ABSTRACT TRUNCATED AT 400 WORDS)