ABSTRACT
Parameters of cardioelectric field on body surface and propagation of excitation in ventricular myocardium during initial activation were studied using multichannel synchronous electrocardiotopography. It was shown that inversion of areas of negative and positive potentials of cardioelectric field on body surface at the moment of excitation propagation to the epicardium reflected changes in the main direction of excitation wavefront in ventricles.
Subject(s)
Ventricular Function , Animals , Body Surface Potential Mapping/methods , Dogs , Electrophysiologic Techniques, Cardiac/methods , Female , Male , Myocardium , Time FactorsABSTRACT
Electrical pacing of the apex, base, and free wall of the heart right and left ventricles, as well as the left ventricle's interventricular septum revealed that localisation of the ectopic focus determined the sequence of ventricular depolarisation, the site formation, and the pathway of displacement of the areas' positive and negative potentials and their extrema on the thoracic surface. Time of the mutual movement (inversion) of positive and negative zones on the body surface was found to depend on the pacing site in the wall of ventricles.
Subject(s)
Pericardium/physiology , Animals , Dogs , Electric Stimulation , Electrophysiology , Ventricular FunctionABSTRACT
The depth of the myocardial wall ectopic focus was found to affect spatial and temporal characteristics of the depolarization process in the heart ventricular surface. Duration of the ventricular epicardial depolarization under the ectopic foci located in subendocardial and intramural layers of the myocardium was shorter than in epicardial stimulation of the ventricles. A dependence of the ectopic excitation duration on the pacing site localization in the epicardium, was revealed. The shortest duration of the depolarization occurred under electrical stimulation of the apex and ventral part of the interventricular septum, whereas the longer one--under pacing the left ventricular base.