CIRCULAR STRAIN AND ROTATION OF LEFT VENTRICULAR BASAL SEGMENTS IN HYPERTROPHIC CARDIOMYOPATHY

Abstract

Highlights The relationship between the rotational mechanics of the basal left ventricular segments and the geometric model of the mitral valve in patients with hypertrophic cardiomyopathy depending on the gradient of obstruction in the left ventricular outflow tract is presented in the research. AbstractBackground. Hypertrophic cardiomyopathy is a common genetically determined disease of the heart muscle. Outflow tract obstruction and mitral regurgitation are the principal features of the disease. Previously, it was believed that these phenomena were primarily caused by the static component of obstruction-interventricular septum hypertrophy. Recently, however, attention has been paid to its dynamic component – SAM syndrome, namely, the role of the mitral valve apparatus in the pathogenesis of the obstructive form of hypertrophic cardiomyopathy. The features of one of the components of the mitral valve apparatus – the basal segments of the left ventricle adjacent to the mitral valve fibrous ring – has not been sufficiently studied.Aim. To evaluate the relationship between rotation and deformation of the basal segments of the left ventricle and 3D morpho functional parameters of the mitral valve in hypertrophic cardiomyopathy.Methods. The study involved 106 patients aged 23 to 78 years: 65 patients with obstructive form of hypertrophic cardiomyopathy, 13 patients with non-obstructive form of the disease, 18 patients with arterial hypertension and left ventricular hypertrophy, and 10 patients without left ventricular hypertrophy and mitral valve lesions. The complex of clinical and instrumental research methods consisted of medical interview, physical examination, standard transthoracic echocardiography (expert-level ultrasound system Vivid E9 (GE Healthcare)), Speckle Tracking Imaging (2D strain) technology to assess the deformation and rotation of the basal segments of the left ventricle, transesophageal echocardiography and real-time three-dimensional visualization of the mitral valve from the transesophageal access followed by post-processing three-dimensional quantitative reconstruction of the mitral valve.Results. Global strain and strain rate of the LV at the level of the basal segments, rotation and rotation rate in patients with hypertrophic cardiomyopathy, arterial hypertension with left ventricular hypertrophy and persons with an unchanged mitral valve did not differ significantly. In patients with the obstructive form of hypertrophic cardiomyopathy, global circumferential strain at the level of the basal segments of the left ventricle correlated with features of mitral valve annulus geometry (namely, anterolateral-posteromedial, commissural diameters and sphericity index of the mitral valve annulus) and the angle of the anterior mitral valve leaflet. Rotation at the level of the basal segments correlated with the anteroposterior diameter, height, sphericity index and area of the mitral valve annulus, as well as the length and area of the anterior leaflet, and the area of the posterior leaflet.Conclusion. Rotation and deformation of the basal segments of the left ventricle correlate with indicators of the geometry of the mitral valve fibrous ring as assessed by three-dimensional quantitative reconstruction.