REDUCTION OF ARRHYTHMIAS IN PRIMARY HYPERPARATHYROIDISM, BY PARATHYROIDECTOMY, EVALUATED WITH 24 HOUR ECG MONITORING

Hypercalcemia may induce arrhythmias. There are no data on the prevalence of arrhythmias in primary hyperparathyroidism (PHPT) in daily life. Aim of the study was to investigate both the prevalence of arrhythmias in patients with PHPT compared to controls and the impact of parathyroidectomy, evaluated by 24 hour electrocardiogram (ECG) monitoring. DESIGN: This is a randomized study. METHODS: 26 postmenopausal women with PHPT and 26 controls were enrolled. PHPT patients were randomized to two groups: 13 underwent parathyroidectomy (Group A) and 13 were followed-up conservatively (Group B). After 6 months, patients were studied again. Each patient underwent mineral metabolism biochemical evaluation, bone mineral density measurement, standard ECG and 24 hour ECG monitoring. RESULTS: PHPT patients showed higher calcium and parathyroid hormone compared to controls and a higher prevalence of both supraventricular (SVBPs) and ventricular premature beats (VPBs) during 24 hour ECG monitoring. Group A and B, showed no differences in mean baseline biochemical values and ECG parameters. Mean value of QTc in PHPT groups was in the normal range at baseline, but significantly shorter than controls. A negative correlation was found between QTc and ionized calcium levels (r = - 0.48, p<0.05). After parathyroidectomy, Group A had a significant reduction in SVPBs and VPBs compared to baseline and restored normal QTc. Group B showed no significant changes after a six month period. CONCLUSIONS: The increased prevalence of SVPBs and VPBs is significantly reduced by parathyroidectomy and it is mainly related to the short QTc caused by hypercalcemia.