In vivochronic carvedilol treatment in rats attenuatesex vivoregional infarction of the heart

OBJECTIVE: Carvedilol is an alpha-and beta-blocking agent with antioxidant properties. We examined if treatment with carvedilol in vivo protected the heart against ischemic injury ex vivo. METHODS: Isolated hearts from treated rats (80 mg/kg/day) were subjected to 30 min regional ischemia. Hearts from non-treated animals received either no drug, 10 min carvedilol (1 microM) acute or ischemic preconditioning (IP) by 5 min ischemia +5 min reperfusion prior to regional ischemia. In separate experiments isolated hearts were subjected to 15 min global ischemia and 30 min reperfusion. RESULTS: Infarct size was significantly reduced by ischemic preconditioning or by chronic carvedilol treatment (9.0+/-0.9% and 7.2+/-1.9% of risk zone infarcted, respectively, vs. 33.8+/-6.4% in control hearts, mean+/-SEM, p < 0.05). Recovery of left ventricular developed pressure after global ischemia was not improved by carvedilol. Post-ischemic rise in left ventricular end diastolic pressure was, however, attenuated by chronic carvedilol treatment. CONCLUSION: Chronic in vivo but not acute ex vivo pretreatment with carvedilol significantly limited infarct size in isolated rat hearts.