Table 3

American College of Cardiology/American Heart Association guidelines for surgery for non-ischaemic severe mitral regurgitation

LV, left ventricular, MR, mitral regurgitation.
Class I (evidence and/or general agreement that surgery is useful and effective)
    ▸ Symptoms caused by mitral regurgitation (acute or chronic)
    ▸ Asymptomatic patients with severe MR and mild-moderate LV dysfunction defined as an:
        –ejection fraction 30–60% and
        –end systolic dimension 45–55 mm
Class IIa (conflicting evidence and/or divergence of opinion but the weight of evidence/opinion favours surgical intervention)
    ▸ Asymptomatic patients with normal LV function and
        –atrial fibrillation or
        –pulmonary hypertension (>50 mm Hg at rest or >60 mm Hg with exercise)
    ▸ Asymptomatic patients with
        –ejection fraction 50–60% or
        –end systolic dimension 45–55 mm
    ▸ Severe left ventricular systolic dysfunction (ejection fraction <30% and/or end systolic dimension >55 mm) if chordal preservation is highly likely