Beta-blockade reverses regional dysfunction in ischemic myocardium.
To determine the protective effect of oxprenolol-induced beta-blockade on the compromised myocardium (critical constriction of the left anterior descending coronary artery) against the adverse effect of high concentrations of halothane, halothane dose-response curves were obtained in six dogs in each of three phases: preconstriction (control), critical constriction, and critical constriction with the addition of 0.3 mg/kg intravenous oxprenolol. The extent of depression of ventricular function was essentially the same in the three phases. However, at high halothane concentrations (2.0% inspired), the depression of systolic shortening in the compromised segment was significantly minimized after oxprenolol so that shortening was 10.2% +/- 1.8 instead of 6.5% +/- 1.4 (P less than 0.05); moreover the large increase in postsystolic shortening observed during critical constriction was abolished after oxprenolol. This suggests a protective effect of oxprenolol on regional myocardial function in the presence of critical constriction, possibly by an effect on myocardial metabolism or endocardial blood flow.
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000188:drug therapy* / Q000503:physiopathology; D004195:Disease Models, Animal; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D006221:Halothane; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D010096:Oxprenolol / Q000627:therapeutic use; D013599:Systole / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D010096:Oxprenolol; D006221:Halothane