Three-dimensional echocardiography for the evaluation of hypertrophic cardiomyopathy patients: relation to symptoms and exercise capacity

Abstract

Patients with hypertrophic cardiomyopathy may exhibit impaired functional capacity, associated with increased morbidity and mortality. Systolic function is one of the determinants of functional capacity. Early identification of systolic disfunction may identify patients at risk for adverse outcomes. Myocardial deformation parameters, derived from three-dimensional (3D) speckle-tracking echocardiography (3DSTE) are useful tools to assess left ventricular systolic function, and are often abnormal before a decline in ejection fraction is seen. The aim of this study was to evaluate the correlation between myocardial deformation parameters obtained by 3DSTE and functional capacity in patients with hypertrophic cardiomyopathy. Seventy-four hypertrophic cardiomyopathy adult patients were prospectively evaluated. All patients underwent a dedicated 2D and 3D echocardiographic examination and cardiopulmonary exercise testing (CPET). Values of 3D global radial (GRS), longitudinal (3DGLS) and circumferential strain (GCS) were overall reduced in our population: 99% (n = 73) of the patients had reduced GLS, 82% (n = 61) had reduced GRS and all patients had reduced GCS obtain by 3DSTE. Average peak VO₂ was 21.01 (6.08) ml/Kg/min; 58% (n = 39) of the patients showed reduced exercise tolerance (predicted peak VO₂ < 80%). The average VE/VCO₂ slope was 29.0 (5.3) and 16% (n = 11) of the patients had impaired ventilatory efficiency (VE/VCO₂ > 34). In multivariable analysis, 3D GLS (β₁ = 0.10, 95%CI: 0.03;0.23, p = 0.014), age (β₁ = -0.15, 95%CI: -0.23; -0.05, p = 0.002) and female gender (β₁ = -5.10, 95%CI: -7.7; -2.6, p < 0.01) were independently associated with peak VO₂. No association was found between left ventricle ejection fraction obtain and peak VO₂ (r = 0.161, p = 0.5). Impaired myocardial deformation parameters evaluated by 3DSTE were associated with worse functional capacity assessed by peak VO₂.

Keywords: Cardiopulmonary exercise testing; Functional capacity; Hypertrophic cardiomyopathy; Left ventricular deformation parameters; Three-dimensional speckle-tracking echocardiography.