The echocardiographic and radio-nuclide angiographic abnormalities in children after scorpion envenomation with L. quinquestriatus, were evaluated. Five children were severely hypertensive, one of them in respiratory failure and another had pulmonary edema. The results revealed poor global contractility 12-15 hr after the sting in three patients. The radionuclide angiograms also revealed poor contractility with low ejection fraction. There was enzymatic evidence of myocardial damage. The changes observed in the echocardiograms and radionuclide angiograms were attributed to catecholamine induced myocardial ischemia. The abnormalities observed suggest that systolic dysfunction plays a role in the pathogenesis of heart failure in scorpion envenomation, in addition to a decrease of left ventricular compliance and increased impedance to left ventricular emptying. The beneficial effects of nifedepine in hypertension and other cardiovascular manifestations justify the routine use of afterload reduction in children with cardiovascular manifestations after scorpion envenomation.