There is no information in the literature on the mechanobiological characteristics of mitral valve chords in living humans. All examinations were carried out on tissues taken from animals, either from cadavers or from frozen human tissues. The objective is to determine mechanobiological and histological characteristics of the mitral valve chords in living humans, as well as to compare differences in elasticity in different groups (Group A: patients with mitral valve prolapse versus Group B: patients with restrictive ischemic mitral valve).