[State of the "contraction-relaxation" mechanism and the bioelectric activity of the myocardium in acute arterial occlusion].
The results of 57 experiments on adult mongrel dogs are shown. Acute occlusion of the terminal aorta was reproduced by means of a balloon catheter. The pressure in the cavity of the left ventricle and in the office of the aorta and the ECG were recorded synchronously. The load experienced by the heart grew by the 6th hour of occlusion of the terminal aorta. This is attended by disorders in excitability and trophics of the myocardium and inhibition of the rate of myocardial contractions. At the same time the potency of the system of myocardial relaxation grows. By the 12th hour of occlusion of the terminal aorta, not only are the myocardial contractility and bioelectric activity impaired, but the capacity of the myocardial relaxation mechanism diminishes. The restoration of the circulation in the involved extremities is attended with further inhibition of the main functions of the heart. A new index of the functional condition of the myocardium, the restoration index, is proposed.