Ventricular function in the newborn lamb
- 30 April 1965
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Legacy Content
- Vol. 208 (5), 931-937
- https://doi.org/10.1152/ajplegacy.1965.208.5.931
Abstract
The present study was initiated with the objective of evaluating in the newborn those aspects of ventricular mechanics which form the basis of the Frank-Starling relation, and which permit a determination of changes in the inotropic state of the heart. Left ventricular function was studied in lambs, 12 hr to 5 days old, utilizing a preparation designed to permit control and measurement of systemic arterial pressure (AP), cardiac output, heart rate (HR), and temperature. Continuous measurements of arterial Po2 and pH were made. These data permitted the construction of ventricular function curves relating stroke volume, mean ejection rate, and stroke work and power to left ventricular end-diastolic pressure, at constant AP and HR. In all preparations the Frank-Starling relation was found to be operative. Norepinephrine infusion, 1–2 µg/kg per min, resulted in a substantial increment of both force and speed parameters, thereby demonstrating the ability of the newborn heart to alter its inotropic state. Severe metabolic acidosis did not inhibit the response of the myocardium to norepinephrine.Keywords
This publication has 12 references indexed in Scilit:
- Cardiovascular responses to ischemia, hypoxia, and hypercapnia of the central nervous systemAmerican Journal of Physiology-Legacy Content, 1963
- Afterload as a primary determinant of ventricular performanceAmerican Journal of Physiology-Legacy Content, 1963
- REGULATION OF VENTRICULAR AND ATRIAL CONTRACTION BY CAROTID SINUS1962
- Effects of Metabolic Acidosis on Ventricular Isometric Systolic Tension and the Response to Epinephrine and LevarterenolCirculation Research, 1960
- Regulation of Ventricular Contraction by the Carotid SinusCirculation Research, 1960
- Baroreceptor reflexes in new‐born rabbitsThe Journal of Physiology, 1960
- Anoxia, oxygen consumption and cardiac output in new-born lambs and adult sheepThe Journal of Physiology, 1959
- The increase in oxygen consumption in the lamb after birthThe Journal of Physiology, 1959
- The patency of the ductus arteriosus in newborn lambs and its physiological consequencesThe Journal of Physiology, 1955
- Changes in the lungs of the new‐born lambThe Journal of Physiology, 1953