Different effects of carvedilol, metoprolol, and propranolol on left ventricular remodeling after coronary stenosis or after permanent coronary occlusion in rats.

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Abstract
Background — Although carvedilol attenuates left ventricular (LV) remodeling in coronary occlusion-reperfusion, it is not known whether it attenuates ischemic LV remodeling because of coronary stenosis (CS) or permanent coronary occlusion (CO). Methods and Results — We administered a vehicle, carvedilol, propranolol (2, 10, and 30 mg/kg per day, each), metoprolol (6, 30, and 90 mg/kg per day), or bunazosin (0.2 and 1 mg/kg per day), orally for 12 weeks to a total of 608 rats with CS or CO. In these groups and the sham (n=40), we assessed LV function by echocardiography, CS severity, myocardial blood flow and coronary flow reserve, serum ascorbyl free radical, and vitamin C. Both CS and CO increased LV end-diastolic and end-systolic diameters and decreased ejection fraction. The 4 agents failed to attenuate LV remodeling caused by CO. In contrast, the 3 β-blockers attenuated ( P Conclusions — The effects of β blockade on ischemic cardiac dysfunction seem to depend on the different properties of the β-blockers and the doses used. Among the β-blockers tested, carvedilol provided potent cardioprotection for compromised ischemic but viable myocardium rather than for infarcted myocardium.