Independence of ventricular breakthrough sites from pacing site in normal dog hearts

The authors previously (1983) studied the spread of excitation on the ventricular surface of exposed dog hearts during normal sinus rhythm. They observed 15-24 breakthrough (BKT) sites on the anterior right and left ventricular surface and 15 sites on average on the postero-inferior surface. The authors hypothesized that the location of the epicardial BKT sites might be related to the location of the underlying Purkinje-myocardial junctions. To test this hypothesis they have paced seven exposed dog hearts from two or more epicardial BKT sites and also from several non-BKT epicardial locations. The results they report support the hypotheses.<>