Mitral regurgitation

Mitral regurgitation (MR) is an abnormal backflow of blood from left ventricle to left atrium due to an insufficiency of mitral valve. This inadequacy of mitral valve is a more common finding in men and could be both, acute and chronic.

A disruption in any part of the apparatus (mitral annulus, leaflets, chordate tendineae and papillary muscles) results in MR. Common etiologies include;

  • Ischemic heart disease
  • Mitral valve prolapse (MVP)
  • Rheumatic heart disease
  • Infective endocarditis
  • Annular calcification
  • Cardiomyopathy

Clinical manifestations of the disease depend on its chronicity and etiology. With a CAD and MI being an underlying cause, symptoms of LV failure become evident:

  • Dyspnea
  • Orthopnea
  • Paroxysmal nocturnal dyspnea

Rapid volume overload results in pulmonary edema, which is one of the earliest findings in such cases. Chronic MR patients on the other hand may remain asymptomatic for years, with a normal exercise tolerance till LV dysfunction develops with typical symptoms (Sob, fatigue, dyspnea on exertion). Severe and chronic MR results in right sided dilation and failure, characterized by:

  • Edema
  • Ascites
  • Anorexia
  • Palpitations

Pulmonary hypertension is a late finding and physical examination of the patients with MR reveals:

  • Distended neck veins
  • 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 lung
  • Enlarged liver
  • Swelling in ankle

Investigations carried out to visualize heart valve structure and function include ECG (LV hypertrophy and LA enlargement), chest X-ray (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;

  • Diuretics
  • Digitalis
  • Anticoagulants
  • Anterior vasodilators

Surgery is the only treatment proven to improve symptoms and prevent heart failure [1]. 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 candidates for surgery too.

References

[1] Enriquez-Sarano M, Akins CW, Vahanian A. Mitral regurgitation. Lancet. 2009 Apr 18;373(9672):1382-94