Estimation of the Residual Volume of the Ventricle of the Dog's Heart by Two Indicator Dilution Technics

A dye dilution and an electric conductivity method for measuring end-diastolic volume and stroke volume of the left ventricle are described, and equations for the calculation of stroke volume are given. When dye is injected "instantaneously" into the left ventricle during diastole, the aortic dye concentration-time curve obtained is a step-like curve and not a smooth curve. The ventricle empties itself in a "fractional" manner, approximately 46 per cent of its end-diastolic volume being ejected with each stroke and 54 per cent remaining in the ventricle at the end of systole.