Relationship of 3D left ventricular mass with systolic and diastolic function indices in hypertrophic cardiomyopathy

Purpose: Massive left ventricular (LV) hypertrophy is associated with an increased risk of sudden death in hypertrophic cardiomyopathy (HCM). Due to the highly asymmetric distribution of hypertrophy, three-dimensional echocardiography (3DE) enables the most accurate approach for quantifying LV mass (LVM) by ultrasound. We aimed: (I) to assess 3DLVM in HCM pts and its correlation with indices of LV systolic and diastolic function; (II) to compare the relationship between 3DLVM and conventional measurements of LV hypertrophy. Methods: In 32 pts with HCM (51+13 yrs, 20 men), 2D and 3D LV datasets were analyzed using GE EchoPac BT12 software. LV hypertrophy was quantified by M-mode LVM, 3DLVM and maximal wall thickness (MWT) on 2D images and on 3D multi-slice (after dataset alignment). LV systolic function was assessed by 3D ejection fraction (LVEF), peak global 2D (2DLS) and 3D longitudinal strain (3DLS), 3D circumferential strain (3DCS) and 3D area strain (3DAS). Strain parameters were analyzed as absolute values. Biplane left atrial volume (LAV), average myocardial diastolic velocities (e’ average), E/e’ and pulmonary vein flow (S/D and Ar-A)were recorded as indices of LV diastolic function. Results: 3DLVM had a close correlation with LV longitudinal deformation: r=-0.74 for 2DLS and -0.70 for 3DLS (p,0.001 for both). 3DLVM had a modest inverse relationship with LVEF (r=-0.46), 3DCS (r=-0.46) and 3DAS (r=-0.49, p,0.01 for all). Among LV diastolic function indexes, 3DLVM was related with e’average (r=-0.50, p=0.005), E/e’average (r=0.40, p=0.03)andLAV(r=0.42, p=0.02).No correlations of 3DLVM with pulmonary vein profile were found. There was a closer relationship between 3DLVM and 3DMWT (r=0.65), than with 2DMWT (r=0.59). M-mode LVM significantly overestimated LV hypertrophy in comparison with 3DLVM (306.5 g vs 202.8 g, p,0.0001), and showed a fair correlation with 3DLVM (r=0.73). Conclusions: 3DLVM correlated better with longitudinal LV systolic function than with circumferential function and diastolic function indices in HCM. 3DLVM had only afair relationship with conventional 2D indices of LV hypertrophy, reflecting the limitations of 2D imaging in assessing its extent and asymmetric distribution in HCM