Left Ventricular Ejection in Conscious Dogs:
II. Determinants of Stroke Volume
Some factors affecting stroke volume were investigated in conscious dogs in which left ventricular outflow was measured with an electromagnetic flowmeter. Stimulation of the heart at constant heart rate, by intracoronary injections of calcium gluconate and isopropylnorepinephrine, or postectopic potentiation failed to produce any increase in stroke volume. By contrast, alterations of posture at constant heart rate with the presumed associated changes in end diastolic dimensions, produced large changes in stroke volume. This resulted from a change in late systolic flow.
- stroke volume
- myocardial contractility
- paired pulse potentiation
- calcium gluconate
- momentum of blood
- unanesthetized dogs
- Accepted February 7, 1966.
- © 1966 American Heart Association, Inc.