Aortometric estimation of stroke volume in the presence of aortic insufficiency.

A formula has been derived for estimating the left ventricular stroke volume (SV) from measurements of the difference between maximum and minimum cross-sectional area of the ascending aorta (am), ascending aorta pulse wave velocity (c) and systolic period (TS): SV=0.54 Ts c am. In open chest dogs, this 'aortometric' formula for estimating SV compared favorably with measurements by the electromagnetic flowmeter method both with and without aortic regurgitation. This suggests that in the presence of aortic regurgitation, the aortic backflow may be estimated from the difference between the aortometric SV measurement and the systemic blood flow estimated by an independent technique.