The Role of cardIac magNeTic rEsonance in surGical Decision Making in Patients With Severe pRimAry miTral rEgurgitation

Mitral regurgitation (MR) is the second most frequent valvular heart disease and the second most frequent indication for valve surgery in Europe. The management of patients with MV prolapse (MVP) and severe MR is mainly guided by symptoms, left ventricular (LV) dimensions and ejection fraction (EF), pulmonary artery systolic pressure (PASP) and atrial fibrillation (AF) occurrence. According to the ESC/EACTS guidelines, surgical treatment of severe primary MR is indicated (recommendation Class I, Level B) in case of: * symptomatic patients considered operable by the Heart Team; * asymptomatic patients with LV dysfunction, intended as a LVEF ≤ 60% and/or LV end-systolic diameter (LVESD) ≥ 40 mm or LVESD indexed for body mass area (LVESDi) ≥ 20 mm/m2; * low-risk asymptomatic patients without LV dysfunction (LVEF \> 60%, LVESD \ 50 mmHg; * significant left atrium (LA) dilation, intended as LA volume index ≥ 60 mL/m2 or diameter ≥ 55 mm * concomitant secondary tricuspid regurgitation ≥ moderate. Surgery should be considered (recommendation Class IIa, Level B) in asymptomatic patients with preserved LV function (LVEF \> 60%, LVESD \ 50 mmHg; * LA volume index ≥ 60 mL/m2 or diameter ≥ 55 mm, provided surgical risk is low, surgery is performed in a Heart Valve Center and a durable MV repair is likely. Preliminary data suggest that in patients with MVP, especially with Barlow's disease phenotype, left-sided chambers' enlargement and functional impairment may be disproportionate related to MR grade. Indeed, patients with BD and ≤ mild-to-moderate MR show larger LA and LV dimensions as compared to controls matched for age, gender and cardiovascular risk factors. These findings chall