title: Maturational changes in myocardial pump performance in newborn lambs.
abstract: We examined the left ventricular stroke volume response to fluid loading in 24 acutely instrumented newborn lambs and the right ventricular response in 12 lambs. Newborn lambs (group 1, ages 2 to 4 days) demonstrated a limited response to acute volume loading for both left and right ventricles. With maturation, the left ventricle exhibited a progressively greater ability to respond to acute volume loading, with greater peak stroke volumes achieved at higher end-diastolic pressures. The response of the right ventricle remained limited at all ages examined, with peak stroke volume achieved at lower end-diastolic pressures. We conclude that postnatal maturation of the left ventricle results in a progressively greater stroke volume response in older lambs, while the response of the right ventricle remains limited.
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D006321:Heart / Q000254:growth & development / Q000502:physiology*; D006439:Hemodynamics; D012756:Sheep; D012965:Sodium Chloride; D013318:Stroke Volume
chemical_list: D012965:Sodium Chloride