Aim. To assess the role of subvalvular structures in the development of mitral valve prolapse in children. Methods. Conducted was an echocardiography investigation with comparative analysis of structural and functional parameters of subvalvular structures in healthy children (50 individuals) and children with mitral valve prolapse divided in two groups: first group - without regurgitation (34 children), the second group - with regurgitation (16 children). Results. In healthy children identified were strong correlation links between echocardiographic indices of the subvalvular structures of the mitral valve and the functional parameters of the left ventricle. The diameter of the anterolateral group of papillary muscles directly correlated with the thickness of the interventricular septum, while the diastolic distance between the papillary muscles - with the end diastolic diameter of the left ventricle. It was established that the following factors may contribute to the pathogenesis of mitral valve prolapse: (1) long papillary muscles and the corresponding chords of the valve, (2) a weak (relative to the norm) contractile ability of the papillary muscles, (3) hyperkinesis of the left ventricular apex, and (4) no relationship between the apical and the global ejection fraction. These factors contribute to the fact that the papillary muscles and chords constrain the mitral valve cusps to a lesser extent during systole, which in turn easily bulge into the left atrium under the influence of systolic blood pressure. Apical hyperkinesis contributes to even closer approximation of the subvalvular structures with the cusps. Conclusion. Mitral valve prolapse is attributed to desynchronization of the function of papillary muscles and of the left ventricle; the development of functional mitral regurgitation during mitral valve prolapse is associated with dyssynchrony of the papillary muscles’ activity.
The role of subvalvular structures in the development of mitral valve prolapse in children