Related Experiment Videos
Hypocalcemic myocardial dysfunction: short- and long-term improvement with calcium replacement
Insights
Hypocalcemia impairs cardiac function, but calcium replacement therapy can restore myocardial performance. Both short-term intravenous and long-term oral calcium therapy significantly improved cardiac output and exercise capacity in patients with hypoparathyroidism.
Area of Science:
- Cardiology
- Endocrinology
- Metabolic Disorders
Background:
- Hypocalcemia, often resulting from surgical hypoparathyroidism, can affect myocardial function.
- Asymptomatic patients with hypocalcemia may still experience subclinical cardiac impairments.
Purpose of the Study:
- To investigate the impact of short- and long-term calcium replacement on cardiac function in hypocalcemic patients.
- To determine the reversibility of hypocalcemia-induced myocardial dysfunction.
Main Methods:
- Studied six asymptomatic patients with hypocalcemia secondary to surgical hypoparathyroidism.
- Measured cardiac output using ascending aortic continuous wave Doppler (minute distance) at rest and during exercise.
- Assessed cardiac function before and after short-term intravenous and long-term oral calcium therapy.
Main Results:
- Intravenous calcium replacement at rest increased cardiac output (minute distance) significantly (p < 0.01) without altering heart rate or blood pressure.
- Peak exercise cardiac output and maximum heart rate increased after long-term oral calcium therapy (p < 0.05).
- Exercise duration was also prolonged following normalization of calcium levels.
Conclusions:
- Hypocalcemia significantly impairs cardiac performance, affecting both resting and exercise-induced cardiac output.
- Calcium replacement therapy, both short-term and long-term, effectively reverses these cardiac impairments.
- Restoration of normal calcium levels improves myocardial function and exercise capacity in hypocalcemic patients.
Abstract:
The effects of short- and long-term calcium replacement on myocardial function in six asymptomatic patients (age 48 +/- 3, mean +/- SEM) with hypocalcemia complicating surgical hypoparathyroidism were studied. Cardiac output was determined by ascending aortic continuous wave Doppler assessment and was measured as minute distance. During intravenous calcium replacement at rest, ascending aortic minute distance increased from 6.75 +/- 1.10 to 9.17 +/- 1.29 m as the calcium level rose from 1.76 +/- 0.08 to 2.06 +/- 0.19 mmol/L without changes in heart rate and blood pressure (p less than 0.01). The peak velocity and acceleration of blood flow derived from Doppler measurement showed a similar rise during calcium infusion. Symptom-limited cycle ergometry was performed before and 3 months after normalization of calcium by long-term oral therapy. Although the resting cardiac output was unchanged, the maximum cardiac output at peak exercise also increased from a minute distance of 11.58 +/- 1.84 to 15.37 +/- 2.28 m (p less than 0.05), together with an increase of maximum heart rate from 136 to 149 beats/min (p less than 0.05). Exercise duration was also prolonged from 11.9 +/- 2.9 to 13.0 +/- 2.8 minutes. Thus hypocalcemia impairs cardiac performance, but this impairment is reversible with calcium replacement.