Surgery for chronic, nonischemic, severe MR is indicated once symptoms occur, especially if valve repair is feasible. Other indications for early consideration of mitral valve repair include recent-onset AF and pulmonary hypeension, defined as a PA pressure >=50 mmHg at rest or >=60 mmHg with exercise. Surgical treatment of chronic, nonischemic severe MR is indicated for asymptomatic patients when LV dysfunction is progressive, with LVEF falling below 60% and/or end-systolic dimension increasing beyond 40 mm. ( Harrison&;s principle of internal medicine,18th edition,pg no.1936 )