Key result
Newborn myocardium requires ~3-fold higher calcium concentrations than adult tissue for maximal inotropic response.
Why the study?
The effects of extracellular calcium and barium on myocardial mechanical function in neonatal versus adult rabbit hearts were not fully characterized.
Does extracellular calcium concentration affect myocardial mechanical function differently in neonatal versus adult rabbit hearts?
Population
Isolated arterially perfused neonatal and adult rabbit hearts
Comparison
Extracellular calcium and barium infusion in neonatal versus adult hearts
Design
Preclinical experimental study
Authors
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Neonatal rabbit data suggest age-specific calcium needs; hypothesis-generating for human developmental myocardial function, no practice change.
Does extracellular calcium concentration affect myocardial mechanical function differently in neonatal versus adult rabbit hearts?
Neonatal rabbit hearts require higher extracellular calcium concentrations to achieve maximal inotropic effects compared to adults, likely due to lower amounts of contractile calcium despite similar sarcolemmal permeability.
JARMAKANI et al. (2019) studied Myocardial mechanical function. Extracellular calcium and barium vs. Adult rabbit hearts was evaluated on Myocardial mechanical function (force of cardiac contraction, developed tension). In isolated rabbit hearts, the maximal inotropic effect of calcium required higher concentrations in newborns (30 mM) than adults (10 mM), indicating less contractile calcium in newborns.