Effects of correction of hypocalcemia on cardiac function in the newborn lamb.
The effect of correction of hypocalcemia on cardiac function in the neonate is unclear. Therefore, we evaluated changes in hemodynamic variables and cardiac contractility in a hypocalcemic neonatal lamb model. Baseline serum ionized hypocalcemia was induced via chelation with intravenous EGTA. Cardiac contractility, measured as end-systolic elastance, did not change with correction of hypocalcemia in this model. In contrast, the variable dP/dt(max), a load-dependent index of contractility, showed an increase with calcium administration while the end-diastolic volume decreased, suggesting that diastolic function or early systolic function had changed. Systemic vascular resistance, cardiac output, and heart rate did not change significantly with correction of hypocalcemia. The results of this study suggest that in our newborn lamb model, cardiac contractility is insensitive to ionized calcium and may reflect cardiac immaturity, but that there may be an effect of calcium administration on diastolic or early systolic function.
Moon
A J
AJ
Division of Neonatology, Department of Pediatrics, University of California, Davis, Calif 95616, USA.
Milstein
J M
JM
Goetzman
B W
BW
Bennett
S H
SH
D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure; D002302:Cardiac Output; D002614:Chelating Agents / Q000627:therapeutic use*; D004533:Egtazic Acid / Q000627:therapeutic use*; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D006439:Hemodynamics; D006996:Hypocalcemia / Q000188:drug therapy* / Q000503:physiopathology; D009200:Myocardial Contraction
D002614:Chelating Agents; D004533:Egtazic Acid