Evaluation of midwall systolic function in left ventricular hypertrophy: a comparison of 3-dimensional versus 2-dimensional echocardiographic indices

Abstract

Objective: This study investigated the sensitivity of 3-dimensional (3D) midwall ejection fraction (EF) (3DEF(mw)) to the presence of left ventricular (LV) hypertrophy (LVH) in comparison with conventional echocardiographic indices for systolic function.

Background: EF and fractional shortening (FS) do not reflect the prognosis of patients with LVH. Midwall mechanics better represent the true function in LVH. However, midwall FS (FS(mw)) interrogates a limited region of LV. We developed a method for determining 3DEF(mw).

Methods: This study compared 3DEF(mw) with 2-dimensional (endocardial EF [EF(endo)], endocardial FS, FS(mw), and systolic tissue velocity) and 3D (3D EF(endo) and mitral annular motion [MAM]) echocardiographic indices in 28 patients with essential hypertension and LV mass index by M-mode greater than 125 g/m(2) versus 21 healthy individuals.

Results: Systolic function assessed by EF(endo), endocardial FS, 3D EF(endo), and systolic tissue velocity did not differ between the two groups, but MAM (11.6 vs 14.0 mm), FS(mw) (14.7 vs 18.2%), and 3DEF(mw) (36.6 vs 44.1%) were significantly decreased in LVH compared with normal. Only 3 parameters correlated significantly with both the M-mode and 3D measurements of LV mass index: FS(mw) (r = -0.74 [M-mode]; r = -0.48 [3D]), 3DEF(mw) (r = -0.63 [M-mode]; r = -0.68 [3D]), and MAM (r = -0.43 [M-mode]; r = -0.36 [3D]). Midwall indices FS(mw) (F = 40.4) and 3DEF(mw) (F = 26.5) better discriminated LVH and normal groups than MAM or endocardial indices.

Conclusions: The 3DEF(mw) method discriminates the systolic function of LVH and normal groups, and correlates with the degree of hypertrophy. By avoiding the limitations of FS(mw) or MAM, 3DEF(mw) provides a more comprehensive metric of systolic function in patients with LVH.