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