A CASE REPORT OF HYPERPARATHYROIDISM WITH BRADYCARDIA

The patient was a 65-year-old man in whom hypercalcemia and irregular bradycardia were found during follow-up observation for chronic pancreatitis. He underwent surgery on the basis of a detailed examination and diagnosis of primary hyperparathyroidism. A preoperative ECG revealed bradycardia with reduced ST in leads II, III and aVF, reduced QT and irregular P wave (serum Ca, 17.4mg/dl; pulse rate, 40/min). The serum Ca level increased transiently by 1.2mg/dl after excision of the tumor, and began to decrease rapidly about five and a half hours later, to become almost normal on the following day. After surgery, the pulse rate was improved, and the reduction of QT and the decrease in ST on ECG were eliminated, yielding regular pulses with sinus rhythm. The effects of hypercalcemia on the vagus nerve and the conduction system of the heart and myocardium have been cited as causes of bradycardia. In our case, involvement of the valgus nerve was suggested by the imporvement in bradycardia with atropine and exercise. In addition, postoperative improvement in wandering-pacemaker and the lack of difference in PQ time before and after surgery suggest influence on the sinoatrial node. Detailed elucidation of the pathogenic mechanism will, however, require further investigation.