Background: Left ventricular (LV) function is sensitive to disorders in calcium metabolism. Most previous reports have focused on the effects of calcium on systolic performance. We studied the acute effect of calcium infusion on LV diastolic function in patients with moderate to severe chronic renal failure (CRF) and secondary hyperparathyroidism (SHP).
Methods: We infused calcium gluconate at a constant rate of 45 mumol/kg/h to 14 patients with severe to moderate CRF and SHP. Our aim was to reach slightly supranormal levels of serum ionized calcium (1.35-1.45 mmol/l). LV diastolic function was assessed by pulsed Doppler echocardiography before and after the calcium infusion. The echocardiographic indices were compared to those of 14 age- and sex-matched healthy controls.
Results: Before calcium infusion the patients had significantly greater LV dimensions than the controls, but there was no differences in the diastolic indices. During calcium infusion, serum ionized calcium increased from 1.18 +/- 0.03 to 1.40 +/- 0.03 mmol/l (P < 0.0001) and plasma intact PTH decreased from 38.6 +/- 5.6 to 9.0 +/- 2.2 pmol/l (P < 0.0001). Calcium infusion did not affect the LV dimensions or fractional shortening. The peak early diastolic velocity (Emax) decreased and peak late diastolic velocity (Amax) increased, and their relationship decreased significantly (1.552 +/- 0.586 vs 1.414 +/- 0.535 m/s, P = 0.03). These changes reflect impairment of LV diastolic function.
Conclusions: Induction of acute hypercalcaemia by calcium infusion impairs LV diastolic function in patients with CRF and SHP.