Mechanism of ventricular extrasystoles with fixed coupling. A theoretical model derived from the concept of longitudinal dissociation in the reentrant pathway of extrasystoles.
An electrocardiogram taken from a 29-year-old man with old myocardial infarction is presented as an exemplary case of ventricular extrasystoles with fixed coupling. To explain the mechanism of ventricular extrasystoles with fixed coupling, a theoretical model is derived from the concept of longitudinal dissociation in the reentrant pathway. In the model, functional longitudinal dissociation divides the reentrant pathway into dual pathways F and S. When a sinus impulse is blocked in pathway F and passes only through pathway S, it becomes a manifest reentrant extrasystole because of marked conduction delay in pathway S. When the sinus rate does not exceed a certain value, such an impulse always becomes a manifest extrasystole with fixed coupling. Part of the impulse passing through pathway S enters pathway. F retrogradely. In some cases, thereafter, it reenters pathway S and initiates ventricular reentrant tachycardia. When, on the other hand, a sinus impulse passes through both of pathways F and S, it becomes a concealed reentrant extrasystole because of insufficient conduction delay in the pathways.
Health Administration Center, Hokkaido University, Sapporo, Japan.
S
S
Kinoshita
G
G
Konishi
Y
Y
Kinoshita
D000328:Adult; D001919:Bradycardia / Q000503:physiopathology; D005117:Cardiac Complexes, Premature / Q000175:diagnosis / Q000503:physiopathology*; D004562:Electrocardiography; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D013610:Tachycardia / Q000503:physiopathology