Mitral Regurgitation

Degenerative mitral regurgitation is now the most common type, when rupture of chordae lead to prolapse of one or both leaflets. Other causes are: rheumatic, bacterial endocarditis and cardiomiopathy; it is also a rare early complication of myocardial infarction (usually inferior) due to a ruptured papillary muscle, doubling mortality even when mild.¹

• Acute mitral regurgitation leads to rapid pulmonary oedema which is life-threatening and requires emergency valve repair.
• Chronic mitral regurgitation is well tolerated but dilatation of the left ventricle eventually causes heart failure and breathlessness.

Auscultation reveals a pansystolic murmur at the apex.

Chronic mitral regurgitation may remain asymptomatic for many years but patients should be investigated before the onset of disabling dyspnoea.

• Chest Xray may show an enlarged left atrium and left ventricle. ¹
• ECG often shows a broad P wave of left atrial enlargement.
• Echocardiography (trans-thoracic and trans-oesophageal) is essential to confirm the diagnosis and assess severity. All patients with mitral regurgitation should be evaluated, even in the absence of symptoms. The grade (severity) is defined by the regurgitant jet into the left atrium. More accurate quantification may be achieved by combining Doppler and echo.

• Pulmonary hypertension
• Left atrial dilatation
• Left ventricular dysfunction.

• Antibiotic prophylaxis for dental surgery.
• Diuretics may improve breathlessness.
• The aim is to monitor and operate before the onset of severe symptoms. Pre-operative assessment involves a coronary angiography.
• ACE inhibitors may palliate LV dysfunction.
• Anticoagulation for atrial fibrillation (target INR is 2-3).
• Cardioversion - for recent onset atrial fibrillation.
• Valve repair has a lower mortality and a better long-term outcome than valve replacement, with no need for long-term anticoagulation; numerous techniques are available depending on the cause of the regurgitation (eg inserting new Teflon chords).
• Valve replacement is needed for acute mitral regurgitation, severe chronic regurgitation, severe LV dysfunction (ejection fraction <30%) and most cases of rheumatic valve disease.

• Asymptomatic patients should be followed every 6-12 months with echocardiography.
• More frequent follow up is required if there is severe regurgitation, atrial fibrillation, pulmonary hypertension or LV impairment.