Structural and Physiological Basis of «Flash» Excitation of Heart Ventricles

The general pathology and pathological physiology

Roshchevskaya I.M., Gulyaeva A.S., Roshchevsky M.P.

Abstract.
The excitation wave propagation in complexly organized ventricles of the pig’s heart has been studied by a method of multi-channel synchronous cardioelectrotopography. In the areas of early and late depolarization, electrophysiologically identified, the analysis of the distribution of fibers of the conducting system has been made by a histological method. It is shown that in the areas of early depolarization the fast propagation of the excitation wave occurs from the subendocardium to the subepicardium (during 8–10 ms) due to numerous large conductive fibers in the myocardial wall. In the areas of late depolarization the propagation of the excitation wave towards subendocardial layers of ventricular free walls happens mainly myogenously for a long period of time (15–20 ms) that is connected with a small number of fibers of the conducting system and the orientation of muscular fibers in these areas.
It is revealed that in ungulates flash activation of the ventricular myocardium is connected with the character of the distribution of the Purkinje fibers transpiercing the whole thickness of the wall.

Key words:
ventricular depolarization, conducting system, working myocardium, ungulate.

Authors:
Roshchevskaya Irina M.
Gulyaeva Anna S.
Roshchevsky Mikchail P.

Laboratory of Comparative Cardiology, Komi Science Centre, Ural Branch, Russian
Academy of Sciences
Kommunisticheskaya, 24, 167982, Syktyvkar, Komi Republic, Russia.
e-mail: compcard@mail.ru