[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.

[Parallel study of the fibrillation and excitation thresholds in the cardiac ventricles in experimental animals]. / Parallel'noe izuchenie porogov fibrilliatsii i vozbuzhdeniia zheludochkov serdtsa v eksperimente na zhivo tnykh.

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. Intravenous 1 mg/kg Propranolol elevated the fibrillation threshold causing a parallel rightward shift in the projection of the stimulus on the force-interval curve and decreasing the exitability of the heart.

[Prevention of ventricular fibrillation during the acute phase of experimentally induced myocardial infarction by affecting the ion and acid-base balance of the heart]. / Profilaktika fibrilliatsii zheludochkov v ostroi stadii eksperimental'nogo infarkta miokarda putem vozdeistviia na ionnoe i kislotno-osnovnoe ravnovesie v serdtse

For the purpose of prevention of ventricular fibrillation in acute coronary insufficiency a multi-component solution was developed that produces a normalizing effect on the acid-base and ion balance disorders in the heart under ischaemia. The injection of this solution into the left atrium sharply elevated the ventricular fibrillation threshold in cats with an occluded coronary artery. The administration of the solution into the left atrium of dogs following an occlusion of the descending left coronary artery prevented the development of fibrillation in all the experiments, while in the control series of experiments it developed in 62% of cases (p less than 0.001). The solution was decided to posses a high antifibrillation activity that manifests itself when the solution is introduced into the left atrium, and the mechanisms of the beneficial effects of the solution are discussed