Mechanisms involved in the development of
parasystole and
extrasystole are substantiated on the basis of vast clinical material (261 patients with
parasystole and 45 with
extrasystole). The use of functional tests employing exercise and
atropine contributed to both the correct diagnosis of
parasystole and
extrasystole and a logical explanation of the mechanisms governing their development. Prolonged ECG recording identified, for the first time ever, the limits of the maximum admissible coupling interval for normotopic
extrasystole, as the preliminary diagnosis of the nature of the
arrhythmia was only made after the said tests.
Parasystole was shown to be rooted in a pathologic automatism, and
extrasystole, in the summation of extrasystolic focus potentials and the principal pacemaker potential during movement as well as the principal pacemaker impulse along the route of the minor circular wave on Purkinje' level. The localization of ectopic foci in
parasystole and
extrasystole confirms the hypothesis of the mechanisms involved in these arrhythmias. A parallel study of
parasystole and
extrasystole defined
parasystole as active heterotopia, and
extrasystole, as passive heterotopia incapable of generating a rhythm.