A 23-year-old patient with ventricular parasystole is described. Detailed analysis of ECG's obtained during 260 hours of Holter monitoring revealed a complex arrhythmia best explained in terms of the occurrence of manifest and concealed re-entry within the parasystolic focus. Re-entry, when manifest, resulted in premature beats coupled to the parasystolic beats, and brief runs of ventricular tachycardia. When concealed, re-entry produced an irregularity in the timing of the parasystolic beats. Re-entry within the parasystolic focus was also induced by sinus beats, giving rise to a pattern of bigeminy. Correlation with data obtained from glass microelectrode studies on canine Purkinje fibers and human cardiac tissue permits speculation regarding the electrophysiologic basis of "protection," and the possible interrelationships between parasystole and other types of ectopic ventricular rhythm.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine