Cardiac conduction in patients with hypercalcaemia due to primary hyperparathyroidism

Clin Endocrinol (Oxf). 1992 Jul;37(1):29-33. doi: 10.1111/j.1365-2265.1992.tb02279.x.

Abstract

Objective: To assess whether hypercalcaemia due to primary hyperparathyroidism is associated with significant cardiac arrhythmias.

Design and participants: The prevalence of cardiac arrhythmias and conduction disturbances was evaluated by 12-lead ECG and 24-hour long-term ECG during pre-surgical hypercalcaemia and after post-surgical normalization of serum calcium values in 20 patients with primary hyperparathyroidism.

Results: After surgery, mean +/- SD calcium levels decreased from 2.85 +/- 0.1 to 2.40 +/- 0.1 mmol/l (P < 0.001). There was a significant increase in QT-intervals (0.36 +/- 0.05 vs 0.39 +/- 0.05) and QTc-intervals (0.38 +/- 0.04 vs 0.42 +/- 0.03) after surgery (P < 0.01). Long-term ECG showed no change in the minimal heart rate 47 +/- 8 vs 48 +/- 7 beats/min or in the longest RR interval 1.6 +/- 0.5 vs 1.6 +/- 0.5 s (P NS). There was no difference in the prevalence of supraventricular or ventricular arrhythmias. No episode of high-grade AV-block was observed before surgery. Circadian heart rate rhythm did not change between investigations.

Conclusions: It is concluded that moderate hypercalcaemia, in spite of causing a shortening of the repolarization phase (QT-interval), has no clinically significant effect on cardiac conduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arrhythmias, Cardiac / etiology*
  • Electrocardiography
  • Female
  • Heart Conduction System / physiopathology
  • Humans
  • Hypercalcemia / complications*
  • Hypercalcemia / etiology
  • Hypercalcemia / physiopathology
  • Hyperparathyroidism / complications*
  • Hyperparathyroidism / surgery
  • Male
  • Middle Aged
  • Parathyroidectomy
  • Postoperative Period