Q-oTc interval and blood calcium levels in newborn infants

Area of Science:

• Neonatal physiology
• Pediatric cardiology
• Biochemistry

Background:

• The Q-oTc interval, reflecting ventricular repolarization, is influenced by serum calcium levels.
• Calcium is crucial for cardiac function, and its levels are particularly sensitive in neonates.
• Critically ill premature infants often exhibit complex physiological derangements.

Purpose of the Study:

• To investigate the relationship between the Q-oTc interval and serum calcium levels (total and ionized) in full-term and premature infants.
• To explore potential differences in this relationship in critically ill premature infants.
• To assess the effect of calcium supplementation on the Q-oTc interval in sick neonates.

Main Methods:

• Measurement of the Q-oTc interval, total serum calcium, and ionized serum calcium in 27 full-term and 77 premature infants.
• Correlation analysis between Q-oTc interval and calcium levels.
• Administration of calcium gluconate infusion to a subset of critically ill premature infants and subsequent Q-oTc interval monitoring.

Main Results:

• A significant correlation between Q-oTc interval and both total and ionized calcium was observed in full-term and healthy premature infants.
• No significant correlation was found in critically ill premature infants, many with central nervous system involvement.
• Calcium gluconate infusion significantly shortened the Q-oTc interval in the sick premature infant group.

Conclusions:

• Serum calcium levels are linked to Q-oTc interval duration in healthy neonates.
• The Q-oTc interval-calcium relationship is disrupted in critically ill premature infants, possibly due to autonomic dysfunction or catecholamine variations.
• Calcium supplementation can normalize Q-oTc interval prolongation in sick premature infants, suggesting a role for calcium in managing cardiac repolarization abnormalities in this population.