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[The "optimal rate" for the heart beat of a homeotherm]
The optimal heart-rate was studied in natural conditions of hemodynamics and on stabilizing the left ventricle load and volume with a balloon. The coronary blood-flow was traced with the aid of electromagnetic fluorometer. Post-occlusion reactive hyperemia estimated reserves of the coronary blood-flow. On stabilizing the left ventricle load and volume, its contractility was higher with faster heart-rate. With the fastest heart-rate, a considerable reserve of the coronary blood-flow was still preserved. Apparently under conditions of natural hemodynamics, the optimal heart-rate (100-180/min) and the decline of contractility with fast heart-rate are due to decrease in filling of the heart caves with the blood per 1 sistole at a constant 1 min volume of the blood-flow.
The optimal heart-rate was studied in natural conditions of hemodynamics and on stabilizing the left ventricle load and volume with a balloon. The coronary blood-flow was traced with the aid of electromagnetic fluorometer. Post-occlusion reactive hyperemia estimated reserves of the coronary blood-flow. On stabilizing the left ventricle load and volume, its contractility was higher with faster heart-rate. With the fastest heart-rate, a considerable reserve of the coronary blood-flow was still preserved. Apparently under conditions of natural hemodynamics, the optimal heart-rate (100-180/min) and the decline of contractility with fast heart-rate are due to decrease in filling of the heart caves with the blood per 1 sistole at a constant 1 min volume of the blood-flow.