Background: Dilated cardiomyopathy (DCM) is characterized by remodeling of the prolate shape of the left ventricle (LV) to a spherical one, but LV remodeling in cardiomyopathy due to ischemic heart disease (IHD) can ultimately render a similar appearance. We aimed to utilize 3D echo analysis to identify novel LV morphometric criteria to discriminate between these two cardiomyopathies (CMP).
Methods: 3D echo (Philips ie33; x5) was performed on patients with IHD (n= 20), DCM (n=19) and controls (n=16). CMP patients were matched for age, gender, LV volumes and ejection fraction. The LV endocardial surface of 3D echo datasets were traced in 4 orthogonal planes in end-systole (ES) and end-diastole (ED) utilizing customized software (Omni4D) for all patients. A mean radius normalized to body surface area (R/BSA) from edge of reconstructed LV to a centroid line axis was plotted from base to apex positions. Position of radii was expressed as % from base to apex (1-100 respectively). Point-by-point normalized radii were compared among groups and optimal cut-off values separating between the CMP patients were validated in a separate group of DCM (n=5) and IHD (n=6) patients matched for LV volumes and ejection fraction.
Results: ES R/BSA values were significantly higher in DCM vs IHD patients at positions #19-77, and ED R/BSA values were higher at positions #36-57. ROC analysis showed ES R/BSA at positions #31-42 to hold the best discriminative capacity for DCM (AUC=0.72), with a sensitivity of 73.7%, specificity of 70% and accuracy of 71.8%. Multivariate analysis-based model including gender, HTN, and ES R/BSA improved accuracy to 76.9%, with a 68.4% sensitivity and 85% specificity. The application of the same model in the validation cohort yielded close discriminative capacity (72.7%, 60%, and 83.3% respective values).
Conclusions: Standardized ES radii in the mid-part of the LV provide a useful noninvasive tool for discriminating DCM vs IHD.
