Three-Dimensional Echocardiographic Mitral Valve Quantification in Functional Mitral Regurgitation: Comparison Between Ischemic and Dilated Cardiomyopathy

Background: Functional mitral regurgitation (FMR) is a common complication of systolic heart failure resulting from left ventricular remodeling that distorts mitral annular geometry and subvalvular apparatus. Because FMR is fundamentally a three-dimensional (3D) geometric disorder, two-dimensional echocardiography may not adequately characterize annular non-planarity, leaflet tethering asymmetry, and tenting geometry—key determinants of etiology and severity. Aim: To evaluate 3D transesophageal echocardiography (3D TEE)–derived mitral valve quantification (MVQ) in differentiating mitral geometric patterns between ischemic cardiomyopathy (ICM) and dilated cardiomyopathy (DCM), and to determine the relationship between MVQ parameters and MR severity. Methods: This cross-sectional observational study (May 2024–July 2025) included 50 patients with cardiomyopathy and moderate or severe FMR (DCM n=25; ICM n=25), classified by coronary angiography/coronary CT angiography. Standard echocardiography and 3D TEE MVQ analysis were performed. Spearman correlation assessed associations with MR severity, and ROC analysis evaluated discriminatory performance between ICM and DCM. Results: MVQ demonstrated significant geometric discrimination between DCM and ICM in non-planar angle (163.04±7.33° vs 157.92±8.15°, p=0.023), anterior leaflet angle (34.52±4.46° vs 27.16±3.31°, p<0.001), and posterior leaflet angle (41.72±4.87° vs 52.48±4.52°, p<0.001), reflecting a posterior-dominant asymmetric tethering phenotype in ICM. Tenting height (r=0.823), tenting area (r=0.820), and annular A–P diameter (r=0.801) showed the strongest correlations with MR severity (all p<0.001). ROC analysis demonstrated good discrimination for non-planar angle (AUC 0.793; cut-off 162; specificity 95.0%) and posterior leaflet angle (AUC 0.743; cut-off 49). Conclusion: 3D TEE-derived MVQ provides objective etiologic discrimination between ICM and DCM and identifies tenting geometry as the principal determinant of MR severity.