[Antifibrillatory activity of propranolol in experimental myocardial infarct and its cardiodepressive and hypotensive action]. / Antifibrilliatornaia aktivnost' propranolola pri éksperimental'nom infarkte miokarda i ego kardiodepressivnoe i gipotenzivnoe deistvie.

In experiments in nembutal anesthetized dogs the authors studied the dependence between the antifibrillation activity of propranolol, which was appraised according to the value of the ventricular fibrillation thresholds and the rate of spontaneous fibrillation after occlusion of the coronary artery, and the cardiodepressive and hypotensive action of this agent. It is shown that it is possible in principle to preserve the antifibrillation activity of propranolol infused intravenously in a dose of 1 mg/kg for correcting its cardiodepressive and hypotensive effect in combined intravenous infusion of 0.02 mg/kg corglycon. It is concluded that there is no dependence between antifibrillation activity and the cardiodepressive and hypotensive effects of propranolol.

[Ventricullar fibrillation in the acute stage of myocardial infarct. II. The characteristics of the heart functional changes in experimental myocardial infarct complicated by ventricullar fibrillation]. / Fibrilliatsiia zheludochkov v ostroi stadii infarkta miokarda. Soobshchenie II. Osobennosti izmenenii funktsii serdtsa pri éksperimental'nom infarkte miokarda, oslozhnennom fibrilliatsiei zheludochkov.

In acute experiments on dogs, occlusion of the anterior descending branch of the left coronary artery induced two-phase changes in the cardiac and stroke output (which increased at first and then decreased), drop in arterial pressure, and decrease in the rate of cardiac contractions. The experiments which terminated in ventricular fibrillation were characterized by a number of peculiarities: a more rapid replacement of the phase of primary increase in the cardiac and stroke output by the phase of their decrease; a sharper drop in arterial pressure as compared with that in experiments without fibrillation; marked decrease in cardiac activity which in experiments without fibrillation underwent two-phase changes, it increased a little at first and then decreased.

[Ventricular fibrillation in acute phase of myocardial infarct. 1. Relationship between the development of ventricular fibrillation in myocardial infarct and previous rhythm disorders]. / Fibrilliatsiia zheludochkov v ostroi stadii infarkta miokarda. 1. Zavisimost'vozniknoveniia fibrilliatsii zheludochkov pri infarkte miokarda ot predshestvuiushchikh narushenii ritma

The author analyses the results of experimental studies in dogs and cats, that included a continuous recording of ECG, electrogram and monophase cardiac potentials during 1 hour following coronary artery ligation. The ligation caused bradycardia, but no correlation was found between the degree of bradycardia and the development of extrasystole and ventricular fibrillation. Extrasystole developed in 100% of the experiments in which the coronary artery ligation resulted in ventricular fibrillation, and in 66% and 87% of those without this complication, conducted in dogs and cats respectively. The rate of extrasystole proved important for the prognosis of fibrillation. The number of extrasystoli noted during the mean time of the development of fibrillation was 5 times higher in the experiments with ventricular fibrillation than in those without fibrillation. In the experiments with fibrillation the extrasystoli tended to occur earlier within the cardiac cycle. Of the total number of extrasystoli, grouped extrasystoli comprised 89% in the experiments with ventricular fibrillation, and 21%--in those without fibrillation. Ventricular tachystystole was noted in 50% of the experiments with fibrillation and in 17% of those without this complication. In the experiments complicated by fibrillation the period of ventricular tachysystole was characterized by a gradual shortening of the cardiac cycles.