Mitral valve disease

Mitral stenosis is nearly always a consequence of rheumatic heart disease. It is characterised by a narrowed valve orifice that obstructs flow from left atrium to left ventricle causing a rise in left atrial pressure and left atrial enlargement. Longstanding elevation of left atrial pressures may cause secondary pulmonary hypertension. Breathlessness is the most common symptom. Atrial fibrillation is common. Patients in atrial fibrillation require tight control of heart rate and should be anticoagulated. Patients with moderate or severe symptoms should be offered balloon mitral valvuloplasty if the anatomy is suitable or valve replacement if it is not. Mitral regurgitation may be due to a number of different aetiologies of which degenerative valve disease is the most common. Asymptomatic patients with good left ventricular function can be followed with regular echocardiography but should be considered for surgery at the first sign of symptoms or impaired left ventricular function. Valve repair is superior to replacement in most degenerative valves. Other aetiologies include ischaemic and rheumatic disease. Acute ischaemic regurgitation due to papillary muscle rupture is a surgical emergency. Chronic ischaemic regurgitation is more common and results from distortion of the mechanism of mitral valve closure. Moderate or severe ischaemic regurgitation should be corrected in patients undergoing coronary bypass surgery. Severe symptomatic ischaemic regurgitation may require surgery in its own right. Many ischaemic valves can be repaired. Most incompetent rheumatic valves require replacement.