A 58-year-old man from Delhi presents with progressive dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea for 3 months. On examination, he has an opening snap followed by a low-pitched diastolic murmur at the apex. Chest X-ray shows pulmonary edema and straightening of the left heart border. Which investigation is most appropriate to confirm the diagnosis and assess severity?

Explanation

## Diagnosis and Investigation Strategy **Key Point:** The clinical presentation—opening snap, diastolic murmur at apex, orthopnea, and pulmonary edema—is pathognomonic for mitral stenosis. Transthoracic echocardiography with Doppler is the gold standard first-line investigation. ## Why Transthoracic Echocardiography? ### Diagnostic Capability - Directly visualizes the stenotic mitral valve leaflets - Assesses leaflet thickness, calcification, and commissural fusion - Measures mitral valve area (MVA) using planimetry or continuity equation - Determines severity: mild (MVA >1.5 cm²), moderate (1.0–1.5 cm²), severe (<1.0 cm²) - Evaluates left atrial size and left ventricular function - Detects associated lesions (aortic valve disease, tricuspid regurgitation) ### Doppler Assessment - Measures transmitral pressure gradient - Calculates mean gradient and peak instantaneous gradient - Assesses pulmonary artery pressure (PAP) via tricuspid regurgitation jet **High-Yield:** Echocardiography is non-invasive, widely available, has no radiation, and provides complete anatomic and hemodynamic data in a single test. ## Comparison with Other Investigations | Investigation | Role | Limitation | |---|---|---| | **Transthoracic echo** | First-line; confirms diagnosis, assesses severity | None for diagnosis | | Cardiac catheterization | Invasive hemodynamics; reserved for discordant echo/clinical findings or pre-intervention | Invasive; not needed for diagnosis | | Chest CT angiography | Rules out PE or other cardiopulmonary pathology | Does not assess valve function; high radiation | | Exercise stress testing | Assesses functional capacity and symptom-limited exercise tolerance | Does not diagnose valve disease; contraindicated in symptomatic severe MS | **Clinical Pearl:** In a symptomatic patient with classic signs of mitral stenosis, echocardiography is both diagnostic and prognostic—it guides decisions on medical management, anticoagulation, and intervention (balloon mitral commissurotomy vs. surgical replacement). **Warning:** Do not confuse echocardiography with cardiac catheterization. While catheterization can measure hemodynamic gradients directly, it is invasive and reserved for cases where echo findings are inconclusive or when intervention is planned.