Overview

• Mitral Stenosis → structural anomaly of the mitral valve, resulting in a decreased cross-sectional area of the valve. This impairs blood flow from the left atrium to the left ventricle.
• Most commonly due to rheumatic fever

• Mitral Regurgitation → leakage of blood from the left ventricle into the left atrium due to incomplete closure of the mitral valve during systole
  • Second most common valve disease after aortic stenosis
• Primary MR (caused by direct involvement of the valve leaflets) → mitral valve prolapse (common in young females), rheumatic fever (most common), infective endocarditis
• Secondary MR (caused by changes of LV leading to valvular incompetence) → coronary artery disease (COMMON POST-MI DUE TO PAPILLARY WALL RUPTURE), dilated cardiomyopathy
• Risk Factors → female, low body mass, age, renal dysfunction, prior MI, collagen disorders (eg. Marfan’s), polycystic kidney disease

Making Diagnosis

Clinical Features:

• Mitral Stenosis → dyspnoea, hoarseness (compression of recurrent laryngeal nerve by enlarged left atrium), dysphagia (compression of oesophagus by enlarged left atrium), malar flush, haemoptysis. Later stages have symptoms of right heart failure (PND, orthopnoea).
• MS Auscultation → mid-diastolic murmur, best heard on expiration on left lateral side. Loud S1, opening snap. In severe MS, length of murmur increases and opening snap becomes closer to S2.
• Mitral Regurgitation → dyspnoea, fatigue, palpitations, left-sided heart failure, pulmonary oedema
• MR Auscultation → pansystolic murmur, loudest at apex + radiates to left axilla, quiet S1.

Investigations:

• Transthoracic Echocardiography → reduced mitral valve area in MS, may also see left atrium enlargement and evidence of pulmonary hypertension.