15.9: Mitral Stenosis II: Clinical features and Diagnostic Tests

Mitral stenosis is a heart condition in which the mitral valve, which allows blood to flow from the left atrium to the left ventricle, becomes narrowed or stenotic. This narrowing hinders blood flow and leads to clinical symptoms requiring specific medical evaluations and management strategies. The following overview outlines the clinical symptoms, assessments, diagnostic findings, prevention methods, and treatments for mitral stenosis.

Clinical Manifestations

• Dyspnea (shortness of breath): This is often the first and most common symptom, initially occurring during exertion and later at rest as the condition progresses.
• Fatigue: Patients may experience tiredness and reduced exercise tolerance.
• Palpitations: Often due to atrial fibrillation, which is common in mitral stenosis.
• Orthopnea and paroxysmal nocturnal dyspnea: Difficulty breathing when lying flat and episodes of sudden breathlessness at night.
• Hemoptysis: Coughing up blood may occur due to increased pressure in the pulmonary veins.
• Hoarseness: Rarely, an enlarged left atrium can compress the recurrent laryngeal nerve, causing Ortner's syndrome.
• Thromboembolic events: Conditions like stroke or transient ischemic attacks may occur due to atrial fibrillation. Anticoagulation therapy is often recommended to mitigate this risk.
• Right-sided heart failure symptoms: These include edema (leg swelling) and ascites due to severe pulmonary hypertension and right ventricular failure.

Assessment and Diagnostic Findings

• Physical Examination: May reveal a diastolic murmur best heard at the apex of the heart, a tapping apex beat due to a palpable first heart sound, and signs of pulmonary hypertension.
• Echocardiography: Transthoracic echocardiography (TTE) is the primary diagnostic tool, providing detailed images of the mitral valve anatomy and function and assessing stenosis severity by measuring the mitral valve area and the pressure gradient across the valve. Transesophageal echocardiography (TEE) is particularly useful for better visualization of the mitral valve and left atrium when TTE is inconclusive.
• Electrocardiogram (ECG): Shows P mitrale, indicated by broad, notched P waves in the lead II, suggesting left atrial enlargement, and atrial fibrillation, common in advanced stages, is seen as an irregularly irregular rhythm without distinct P waves.
• Chest X-ray can show evidence of pulmonary congestion and left atrial enlargement, indicated by a straightened left heart border and a double shadow on the right side of the heart.
• Cardiac Catheterization: Confirms the diagnosis and assesses hemodynamic parameters if non-invasive tests are inconclusive or surgical intervention is needed.
• MRI and CT Scans: Provide detailed anatomical and functional information, with cardiac MRI useful in complex cases and CT scans assessing the mitral valve anatomy and calcification.