Myocardial contractility, haemodynamics, and metabolism in acute myocardial infarction. Experimental and clinical study

Abstract

In order to investigate the systemic and central haemodynamics, blood perfusion, and metabolism of the myocardium in acute myocardial infarction (AMI), experiments were carried out in 80 mongrel dogs with experimental AMI, induced by ligation of the descending branch of the left coronary artery, and 183 patients with transmural AMI were clinically followed-up. It was found that after coronary artery ligation the blood flow in the intact myocardial parts increased, whereas in the infarcted zone it decreased. These shifts persisted fairly long after the induction of AMI. Simultaneously the cardiac output markedly tended to decrease in all animals, and this tendency also persisted for the next two days. It was proved that the haemodynamic shifts in question were associated with a decrease in the myocardial biosynthesis of individual fractions of RNA after the coronary artery ligation. The clinical observations confirmed that AMI was accompanied by a decrease in myocardial contractility. The degree of the decrease was directly proportional to the infarct size. The dependence of the changes on the localization of AMI was less marked.