ABNORMAL ELECTROCARDIOGRAMS, BLOOD PRESSURE CHANGES, AND SOME ASPECTS OF THE HISTOPATHOLOGY OFSELENIUM DEFICIENCY IN LAMBS

Experimental selenium deficiency has been studied in a group of lambs weaned early on to a semi‐synthetic diet. Nineteen lambs were used; eleven became selenium deficient, the remaining eight were supplemented with selenium and remained normal. Well‐defined differences, in terms of histopathological changes, developed between the two groups. The dystrophic lesions were mainly found in skeletal and cardiac muscle, and to a lesser extent in the pancreas and diaphragm. Electrocardiograms showed the progressive development of a characteristic abnormality, after the animals had been on the deficient diet for a few weeks. Just before death the ECG pattern became grossly abnormal in some cases, a rise in the T‐wave giving way to an elevated S‐T segment, similar to that seen frequently in myocardial infaretion in man. Paralleling these changes, at least in time, there was a fall in blood pressure especially marked in the limbs, but present to a lesser degree in the rest of the systemic circulation. Taken together, these observations point to the possibility that the fundamental change occurring in selenium deficiency may be circulatory failure. Finally, comparison of the histopathological picture of the lamb and the rat, when both species are reared on the same diet, indicates that entirely different syndromes appear, at first sight, to develop. However, ECG changes previously studied in rats are somewhat similar to those reported here. Skeletal muscle is severely dystrophic in both species. Perhaps subsequent studies will demonstrate that even though the final outcome of selenium deficiency in different species is variable, the initial lesions are closely comparable.