24-hour outpatient ECG as a screening method in patients with primary hyperparathyroidism

Patients with primary hyperparathyroidism are characterized by increased calcium plasma concentrations, which in turn could have a potential to induce ECG changes, especially shortening of the QT interval. Therefore, the aim of this study was to evaluate, whether the routine 24-hours outpatient ECG monitoring could be used for screening the primary hyperparathyroidism.

Totally, 31 patients (mean age, 59.2 ± 12.99 years) with primary hyperparathyroidism were compared to 20 healthy controls. All patients underwent mineral metabolism biochemical evaluation, ultrasound or scintigraphy of the neck, and a 24-hour outpatient ECG. The device detected QT, QTc, and RR intervals during a 24-hour period.

Significantly higher calcium concentrations were confirmed in patients when compared to controls (2.38 ± 0.12 vs 2.92 ± 0.29 mmol/l; p < 0.001). However, no significant differences were found between controls and patients in QT interval and overall heart rate.

Although shortening of the QT interval is a common ECG finding in patients with hyperparathyroidism, it seems that 24-hour outpatient ECG is not suitable for primary hyperparathyroidism screening (Tab. 2, Fig. 4, Ref. 28).