HISTORY OF THE DEVELOPMENT OF SURGICAL TREATMENT OF MITRAL HEART DEFECT (literature review) mitral valve, mitral stenosis, mitral valve insufficiency, surgical treatment of mitral valve defects, chordal-papillary apparatus K. Urmanbetov , M. Asanaliev , Bh. Javed , S. Zhumabaev , R. Kalieva https://doi.org/10.54890/1694-6405