The effect of β-adrenergic blockade on infarct size following experimental coronary occlusion

Summary The effect of Pindolol on myocardial infarct size was studied in 10 open chest dogs. In each animal a sequential occlusion and reperfusion of 2 medium-sized branches of the left coronary artery was performed in the same heart. After occlusion and reperfusion of the control artery the initial dose of Pindolol (0.25 mg/kg body weight) was administered. Thereafter the test artery was occluded, followed by a maintenance dose of Pindolol (0.3 mg/kg body weight).The drug caused a significant decrease in LVP and LV-dp/dt but no change in heart rate. MVO₂ also decreased significantly. Regional myocardial blood flow was measured with the tracer microsphere method. Collateral flow in the perfusion area of the control artery was 11.2±5.9% and in the area of the test artery 10.0±4.4% of normal. No change in the endo/epi ratio as a result of treatment was observed.The area of infarction (p-nitroblue tetrazolium-reaction) was divided by the area of perfusion (angiography). Infarct size, expressed as the percentage of the perfusion area. was 48.2±22.2% in the region of the control artery and 43.0±23.9% in the region of the test artery. The difference was statistically not significant.With 1 table