[Effect of the age of animals on disorders of the contractile function of the heart muscle under stress].

During intensive growth of animals, the main parameters of myocardial contractility were reduced. Poststressor depression of the contraction of isolated papillary muscles was more marked in adult than in young animals. Thus, aging of animals was accompanied by reduced cardiac muscle contraction. It is inferred that strong stress influence might result in a deep depression of the cardiac function in question, threatening the physiological possibilities of adaptation.