Mitral regurgitation (MR) is an abnormal backflow of blood from left ventricle to left atrium due to an insufficiency of the mitral valve. This inadequacy of the mitral valve is a more common finding in men and could be either acute or chronic.
A disruption in any part of the apparatus (mitral annulus, leaflets, chordae tendineae and papillary muscles) results in MR. Common aetiologies include;
- Ischaemic heart disease
- Mitral valve prolapse (MVP)
- Rheumatic heart disease
- Infective endocarditis
- Annular calcification
- Left ventricular dilatation
- Acute myocardial infarction with papillary muscle rupture
Clinical manifestations of the disease depend on its chronicity and etiology. With coronary artery disease (CAD) and myocardial infarction being an underlying cause, symptoms of LV failure become evident:
- Paroxysmal nocturnal dyspnoea
Rapid volume overload results in pulmonary oedema, which is one of the earliest findings in such cases.
Patients with chronic MR, on the other hand, may remain asymptomatic for years, with a normal exercise tolerance until LV dysfunction develops with typical symptoms (shortness of breath, fatigue, dyspnoea on exertion). Severe and chronic MR results in right sided dilation and failure, characterised by oedema, ascites, anorexia and palpitations. Pulmonary hypertension is a late feature.
Physical examination of the patients with MR reveals:
- Irregularly irregular pulse if the patient is in AF (more common in patients with mitral valve disease)
- Distended neck veins if right heart failure is present
- Hyper dynamic and displaced LV impulse
- Brisk carotid upstroke
- Holosystolic apical murmur radiating towards axilla and accompanied by thrill
- S3 with a widely split s2 and soft or absent s1
- S4 may be audible in acute severe MR if the patient is in sinus rhythm
- Crackles in the lung
- Enlarged liver
- Swelling in ankle
Investigations carried out to visualize heart valve structure and function include ECG (LV hypertrophy and LA enlargement), plain chest radiograph (cardiac enlargement with vascular congestion) and echocardiography.
Medical therapy aims at relieving symptoms by reducing pulmonary venous hypertension and increasing forward cardiac output. Drugs given here are;
- ACE inhibitors
- Anticoagulants if atrial fibrillation present
Surgery is the only treatment proven to improve symptoms and prevent heart failure . Criterion for MV replacement is an ejection fraction <60% or LV end systolic diameter of >40mm. Patients with persistent symptoms despite medical therapy, significantly limiting symptoms and severe MR are also candidates for surgery.
 Enriquez-Sarano M, Akins CW, Vahanian A. Mitral regurgitation. Lancet. 2009 Apr 18;373(9672):1382-94.