Abstract
Cardiopathologic and electrocardiographic examinations were carried out on 4-, 8- and 35-week-old DBA/2 and BALB/c mice of both sexes. Both of the electrocardiographic changes (prolongation of QRS duration and PQ-interval, appearance of abnormal P wave and notch in QRS complex, deviation of "ST-segment", and shift of mean electrical heart axis to the left) and pathologic alterations (scatteringly observed small focal myocardial calcification and marked calcification restricted to the myocardium under the right ventricular epicardium) were significantly more frequent and clear in DBA/2 mice than in BALB/c mice, and they became more apparent at 8 weeks of age. Such cardiac disorders as observed in the present study were thought to be free from hypercalcemia because of unchanged serum total calcium concentration.
