[Antifibrillatory activity of propranolol in experimental myocardial infarct and its cardiodepressive and hypotensive action].

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.

[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].

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.

[Parallel study of the fibrillation and excitation thresholds in the cardiac ventricles in experimental animals].

To find the fibrillation threshold under rapidly changing conditions a method of its determination with long-lasting stimuli (100--300 msec) far exceeding the period of the highest vulnerability is described. The figures of the fibrillation threshold found by way of stimulating the heart with short and long impulses were partically identical. Intravenous administration of 4 mg/kg Lidocaine resulted in an increase of the fibrillation threshold in the experimental dogs, without changing the projection of the stimulus producing the fibrillation onto the force-interval curve and at the same time increasing the excitability of the myocardium.