Scorpion venom cardiomyopathy.

Cardiac function was evaluated by serial echocardiography in 30 children affected by scorpion stings. They could be separated into two groups on the basis of the initial echocardiogram. Group 1, consisting of 18 children, had normal left ventricular function, whereas group 2, consisting of 12 children, showed compromised left ventricular function (ejection fraction less than 0.55; fractional shortening less than 27%). In group 2 the left ventricular end-systolic dimension was increased significantly and the interventricular septal thickening fraction was depressed significantly, compared with group 1. Nine children in group 2 showed improvement in all measurements of contractility, usually within 24 to 48 hours. Of the remaining children, one showed no echocardiographic changes and subsequently died. Another child made a slow improvement over several weeks. We conclude that myocardial toxicity is a common and serious complication of scorpion stings in children. Systolic function appears to be affected predominantly. Serial echocardiography is useful to follow changes in left ventricular function, which are generally matched by clinical improvement. Patients who fail to improve within 24 to 48 hours require particularly close observation.