Haemodynamic changes in mitral regurgitation underlie triggering of patient’s symptoms and development of heart failure. A number of endovascular methods for the correction of mitral regurgitation successfully counteract pathological hemodynamics and thus manage to improve both the manifestations of heart failure and the patient's symptoms. This article is a review of the physiology of the mitral valve and the changes that occur in the presence of mitral regurgitation. The peculiarities of the hemodynamics of the left atrium in the conditions of mitral regurgitation and after some types of transcatheter treatment – edge-to-edge correction of the valve with Mitraclip and the implantation of an occluder in paraprosthetic mitral regurgitation are considered. The change in left atrial parameters immediately after correction of the defect is of value both for the assessment of immediate procedural success and for the patient's prognosis.