[Changes in the contractile function of the myocardium in various methods of excluding the heart from the circulation during the surgical correction of acquired heart defects].

Changes in myocardial contractile function were studied during 46 operations with extracorporeal circulation on patients with acquired heart diseases; the operations were performed with the use of cold cardioplegia and electrical fibrillation of the heart. The dependence of the decrease in myocardial contractilicy on the method of cardioplegia, the duration of the heart arrest, and the parameters of extracorporeal circulation is analysed. The results obtained are evidence that it is necessary to improve the method for protecting the myocardium during operations with extracorpeal circulation.