[Repolarization pattern of the ventricular myocardium in pikes].

The study aimed at investigation into the repolarization pattern in the myocardium of fish. Activation times, activation-recovery intervals and repolarization times were determined in the intramural layers of the heart ventricle in eight pikes with multiple plunge electrodes. In the heart ventricle of the pike, the earliest end of repolarization was found in the subendocardium of the base and the subepicardium of the apex, the areas corresponding to the earliest and latest depolarization, respectively.

[Cardiac electric field at the period of depolarization and repolarization of the frog heart ventricle].

Multichannel mapping of electrical field on heart ventricle epicardium and the body surface in frogs Rana esculenta and Rana temporaria was performed at periods of the ventricular myocardium depolarization and repolarization. The zone of the epicardium early depolarization is located on epicardium of the ventricle base posterior wall, while the late depolarization zone--on its apex and on the base anterior wall. The total vector of sequence of the ventricle epicardium depolarization is directed from the base to the apex.

[Ventricular pump function under ectopic excitation of the frog heart].

The ventricular pump function under ectopic excitation of the heart was studied in decapitated and pithed adult frogs Rana temporaria (n = 21) at 18-19 degrees C. The intraventricular pressure was recorded with a catheter via ventricular wall. During pacing of the ventricular base and apex, the systolic pressure decreased (6.

[Cardiac electric field on the epicardial and body surfaces during the period of depolarization and repolarization of ventricular myocardium in pikes].

Body surface and ventricular epicardial potential distributions during the electrocardiographic QRST interval were studied in pikes with the aid of potential mapping. The earliest epicardial activation was observed at the posterior base near the atrioventricular orifice. The areas of the earliest repolarization were found at the apex and the posterior base, whereas the area of the latest repolarization was detected at the anterior base.