Diagnostic Value of Earpiece Dye-dilution Curve in Aortic Insufficiency

Peripheral arterial dilution curves were recorded by earpiece densitometer following injection of dye into a femoral vein, pulmonary artery, left atrium and aortic root in 14 cases with aortic insufficiency and 56 control cases without heart disease during routine cardiac catheterization. Six indices (tpd/ta, tpd/tap, Spread/ta CL/Cr, Cp+ap/Cp, Cp10/Cp) which have been advocated for diagnosis of mitral insufficiency or left-to-right shunt were calculated from the dilution curves. Cp10/Cp showed significantly higher values in aortic insufficiency than in controls, while there were no significant differences in the other 5 indices between both groups. Aortic regurgitation was quantitated by continuous injection of dye into the aortic root and recording from the left ventricle, and the values were compared with Cp10/Cp. There was a positive correlation between Cp10//Cp and aortic regurgitation. It was concluded that the increase in Cp10/Cp is resulted from a flatness of its peak without prolongation of downslope of the dye curve in aortic insufficiency, so that the index is useful for diagnosis of this disease.