Cross-sectional echocardiography III. Analysis of mathematic models for quantifying volume of symmetric and asymmetric left ventricles

Cross-sectional echocardiography was utilized for quantification of volume in 19 formalin-fixed left ventricles in the presence or absence of ventricular symmetry, defined by the ratio of septal-lateral to anterior-posterior diameter. In 10 symmetric ventricles this ratio was 1.23 ± 0.06 (mean ± SEM), whereas in nine asymmetric ventricles the ratio was 1.80 ± 0.07. Area, diameter, and length measurements were obtained from short- and long-axis cross-sectional images of the left ventricle and volume was calculated by five mathematical models previously described. To evaluate the reliability of each model, echocardiographic left ventricular volume was compared by linear regression and percent error analyses to directly measured fluid volume. In symmetric ventricles, excellent correlations (r = 0.996 to 0.967) and reasonable mean percent errors (6% to 31%) were observed for all models. In asymmetric ventricles, models utilizing short-axis area or two short-axis diameters retained high correlation coefficients (r = 0.985 to 0.956) and similar mean percent errors, but standard formulas previously used with M-mode echo and angiography showed lower correlations (r = 0.886 to 0.873) and higher mean percent errors (52% to 54%). Thus, in the presence of ventricular asymmetry, analysis of short-axis areas or diameters with cross-sectional echocardiography is well suited for quantification of left ventricular volumes.