Electrocardiographic Changes in Rats Deficient in Vitamin B 1

Vitamin B₁ deficiency in rats and pigeons has been found to be associated with bradycardia (Birch and Harris 1 ; Drury, Harris and Maudsley 2 ; Carter and Drury 3 ; and Méhes and Péter 4 , 5 ). Changes in the complexes of the electrocardiograms have not been described. As far as one can ascertain, the electrocardiograms obtained in rats deficient in vitamin B₁ were not standardized.

Because of the discrepancy between electrocardiographic findings in deficiency states attributed to vitamin B in man (beriberi, pellagra, polyneuritis) 6 7 8 9 and in animals, a study was undertaken on the effect of vitamin B₁ deficiency on the heart of the rat, as indicated by the electrocardiogram. Nine rats were placed on diets deficient in B₁, consisting of Wesson 10 salt mixture 3.5%, starch 55%, butter fat 8.5%, casein 18% and autoclaved bakers' yeast 15%. The casein was washed with alcohol by a method similar to that of Chase and Sherman. 11 The yeast was autoclaved for one hour at 20 pounds after the addition of 0.1 normal sodium hydroxid. Standardized electrocardiograms using skin copper leads were obtained. During a period of 7 weeks only moderate loss of weight developed. This, together with, the absence of bradycardia and of nervous manifestations, indicated the existence of but partial deficiency. The yeast was therefore autoclaved for 6 hours at 15 pounds at a pH of 8 to 9. After 3 weeks on this modified diet the animals exhibited marked loss of weight, neurological manifestations, bradycardia and changes in the electrical complexes of the cardiogram. The heart rate gradually fell from a normal level of from 564 to 666 per minute (average 581) to from 354 to 134 (average 286).