Cardiovascular actions of amrinone in anesthetized open-chest pigs with an acute mild stenosis in the left anterior descending coronary artery.
A 15 minute reduction of the flow in the left anterior descending coronary artery (LAD) to 50% of baseline caused a 10% decrease in cardiac output in anesthetized open-chest pigs (n = 12), together with a fall in max LV dP/dt (20%), mean arterial blood pressure (15%) and stroke volume (7%), while left ventricular filling pressure rose from 9 +/- 1 to 15 +/- 1 mmHg. The decrease in perfusion of the LAD nourished myocardium was not evenly distributed as endo-epi blood flow ratio decreased from 1.03 +/- 0.05 to 0.50 +/- 0.08. Regional myocardial wall thickening of the ischemic segment decreased from 34 +/- 6 to 7 +/- 3%, while the arterio-coronary venous differences in pH and PCO2 increased five and two fold, respectively. Subsequently, 6 animals received 1 mg X kg-1 plus 50 micrograms X kg-1 X min-1 amrinone for 10 minutes, whereas 6 other animals were treated with saline. In the following 10 minutes cardiovascular performance in the saline-treated animals did not change dramatically, although there was a tendency to further deterioration. Administration of amrinone led to a decrease in left ventricular filling pressure (30%), stroke volume (20%), cardiac output (10%) and mean arterial pressure (20%). There was also a mild positive chronotropic action (15%) and an initial positive inotropic action as indicated by an increase in max LV dP/dt (25%). The positive inotropic effect, however, was short-lasting as max LV dP/dt returned to baseline within 10 minutes after the bolus injection.(ABSTRACT TRUNCATED AT 250 WORDS)
D000676:Amrinone / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000188:drug therapy*; D004195:Disease Models, Animal; D004341:Drug Evaluation; D006439:Hemodynamics / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D013552:Swine; D013997:Time Factors
D001639:Bicarbonates; D000676:Amrinone