[Coupled type of parasystole and its diagnosis].

Fifty patients with arrhythmia of the extrasystole type were examined by means of functional tests (atropine and physical exertion). Parasystole was revealed in 40 and extrasystole in 10 patients. The diagnosis of arrhythmia was based on determining the relative value of the longest pre-ectopic interval (R--R1, P--P1) and the relative value of the preceding cardiac cycle (R--R, P--P) prior to and after the functional tests. Reduction of the relative value of the longest pre-ectopic interval or increase of this interval by less than 10 per cent in the test was observed in extrasystole, an increase of the relative value of this interval by more than 10 per cent was encountered in parasystole. In cases with bigeminal rhythm, reduction of the absolute value of the longest pre-ectopic interval in the tests was characteristic of extrasystole while its increase was characteristic of parasystole.