Myocardial damage induced by tropical rattlesnake (Crotalus durissus terrificus) venom in rats

This article describes the light and electron microscopic appearance of the rat myocardium at various time intervals after the administration of Crotalus durissus terrificus venom by intraperitoneal route. The crotalid envenomation produced small foci of myocardial necrosis scattered throughout the base of the ventricles. These lesions were predominantly perivascular and were associated with slight to moderate interstitial edema as well as infiltration of mononuclear cells and of a great number of mast cells. The first changes appeared 24 hours after envenomation and reached maximal severity after 4 days. By 8 days, the cardiac morphology was comparable to that of control animals except for small foci of interstitial fibrosis at the base of both ventricles-probably attributable to reabsorption of necrotic myofibers and healing-and a small number of degenerated myofibers. The main points concerning these findings are their preferential localization at the base of the heart and the association of the foci of myocytolytic necrosis with a large number of mast cells. On the basis of these data, although nonspecific, the mechanism of venom-induced myocardial damage is discussed. Moreover, these findings call attention to the potential cardiotoxic effect of crotalid poisoning in humans.