Left ventricular volumes by single-plane cineangiography: In vivo validation of the kennedy regression equation

This study was performed to assess the accuracy and reliability of the regression equations of Kennedy et al and Wynne et al in the quantitation of single plane left ventricular (LV) volumes. In 15 patients with normal LV function and without intracardiac shunting or valvular insufficiency, gated equilibrium blood pool scintigraphy was performed simultaneously with the measurement of cardiac output (by thermodilution), after which left ventriculography was performed in the 30 ° right anterior oblique (RAO) projection. From the scintigraphically determined LV ejection fraction (EF) and the ther-modilution-measured stroke volume (SV), absolute LV volumes were calculated. The cineangiographic LV volumes obtained with the regression equation of Kennedy et al closely approximated those calculated by scintigraphy/thermodilution, whereas the volumes determined using the regression equation of Wynne et al were larger (p<0.05) than the calculated volumes. In 204 patients without intracardiac shunting or valvular insufficiency, SV was measured by the Fick or indicator dilution methods, after which single-plane left ventriculography was performed in the 30 ° RAO projection. In the 83 patients without coronary artery disease with normal (n = 69) or depressed (n = 14) LVEF, cineangiographic SV (obtained using the regression equation of Kennedy et al) closely approximated forward SV. Similarly, this relation was excellent in the 142 patients whose LVEFs were ≥ 0.50. In contrast, in the 48 patients whose LVEFs were <0.50 and who had extensive segmental wall motion abnormalities, there was a poor relation between cineangiographic SV (obtained using the regression equation of Kennedy et al) and forward SV. Thus, LV volumes can be measured accurately by single-plane cine-angiography in a 30 ° RAO projection using the area-length method and the regression equation of Kennedy et al, but the reliability of these volumes is poor in persons with extensive segmental LV dysfunction.