Key result
IV oxprenolol improves compromised myocardial systolic shortening ~57% during high halothane exposure.
Why the study?
The protective effect of oxprenolol-induced β-blockade on compromised myocardium under high halothane concentrations was unclear.
Does intravenous oxprenolol improve regional myocardial function in dogs with critical coronary constriction exposed to halothane?
Does intravenous oxprenolol improve regional myocardial function in dogs with critical coronary constriction exposed to halothane?
Absolute Event Rate: 10.2% vs 6.5%
p-value: p=<0.05
Intravenous oxprenolol minimizes the depression of systolic shortening in ischemic myocardium exposed to high concentrations of halothane in a canine model.
Oxprenolol β-blockade may attenuate halothane depression in critically constricted canine myocardium; leaves open any clinical translation.
To determine the protective effect of oxprenolol-induced β-blockade on the compromised myocardium (critical constriction of the left anterior descending coronary artery) against the adverse effect of high concentrations of halothane, halo-thane 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<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.
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Leone et al. (1987) studied Compromised myocardium (critical constriction of the left anterior descending coronary artery) (n=6). Oxprenolol vs. Critical constriction without oxprenolol was evaluated on Systolic shortening in the compromised segment at high halothane concentrations (2.0% inspired) (p=<0.05). Intravenous oxprenolol significantly minimized the depression of systolic shortening in compromised myocardium during high halothane exposure (10.2% vs 6.5%, P<0.05).
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