Propranolol ameliorates exercise-induced regional myocardial dysfunction in dogs.

The effects of propranolol (0.5 mg/kg) on exercise-induced regional myocardial dysfunction were investigated in an animal model with limited coronary reserve. Limited coronary reserve was accomplished in conscious, chronically instrumented dogs by external filling of a hydraulic cuff occluder placed on a coronary vessel which did not impair resting myocardial function but induced severe dysfunction during treadmill exercise. Propranolol led to a distinct reduction of heart rate, myocardial contractility and systolic blood pressure, thereby ameliorating exercise-induced regional myocardial dysfunction.