[Disorders of cardiac contractility caused by hemorrhagic hypotension]

Two-hour hemorrhagic hypotension was induced in outbred male rats. Left-ventricular myocardial contractility was studied at all stages of hypotension on a model of isolated isovolumetrically contracting heart. The contractile function decreased after 60 min of hemorrhagic hypotension, this decrease progressing with hypotension prolongation. The myocardial relaxation mechanisms were more involved, and the pathogenetic factors of cardiac depression were hypoergosis, cardiomyocyte membrane injury, and inhibition of Ca(2+)-Mg(2+)-dependent ATPase of sarcoplasmatic reticulum and sarcolemma.