title: [Problem of narrow fibrous rings in the surgery of heart valves].
mesh_terms: D000293:Adolescent; D001021:Aortic Valve / Q000601:surgery; D001705:Bioprosthesis; D002648:Child; D005069:Evaluation Studies as Topic; D006350:Heart Valve Prosthesis; D006801:Humans; D008943:Mitral Valve / Q000601:surgery; D011474:Prosthesis Design
vernacular_title: Problema uzkikh fibroznykh kolets v khirurgii klapanov serdtsa.