[Interrelation of hemodynamic changes in systemic and pulmonary circulation under experimental myocardial ischemia in cats].
Myocardial ischemia caused inhibition of myocardial contractility, increased pressure in the left atrium, reduced cardiac output and reduced systemic blood pressure. The decrease in cardiac output is due to a combination of the myocardial contractility reduction and that of the outflow of blood from the pulmonary vascular bed. Hemodynamic changes in the arterial part of the systemic circulation are accompanied by shifts in its venous part: reduced blood flow in the anterior and posterior caval veins and a decrease in venous return. The determining factor for reducing the flow of venous blood to the heart during myocardial ischemia is a decrease in cardiac output. Myocardial ischemia of the left ventricle is accompanied by a decrease in pressure and blood flow in the pulmonary artery. The data obtained suggest that the degree of reduction of these indicators of pulmonary hemodynamics depends on the elevated pressure in the left atrium resulting from reduction of the left ventricle contractility. The degree of hemodynamic disorders in systemic and pulmonary circulation in myocardial ischemia depends not only on the size of the zone of myocardial ischemia of the left ventricle, but also on the duration of cessation of its blood supply. We suggest that the time factor is a decisive one with respect to severity of hemodynamic disorders occurring only at a certain, critical, size of the zone of myocardial ischemia.
Tkachenko
B I
BI
Evlakhov
V I
VI
Poiasov
I Z
IZ
Ovsiannikov
V I
VI
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002302:Cardiac Output; D002415:Cats; D006352:Heart Ventricles / Q000503:physiopathology*; D017202:Myocardial Ischemia / Q000503:physiopathology*; D011651:Pulmonary Artery / Q000503:physiopathology; D011652:Pulmonary Circulation