A 32-year-old woman from rural India presents with progressive dyspnea on exertion and orthopnea for 6 months. On examination, she has an opening snap and a low-pitched diastolic murmur at the apex. Chest X-ray shows pulmonary congestion. Which investigation is most appropriate to confirm the diagnosis and assess severity of mitral stenosis?

Explanation

## Investigation of Choice for Mitral Stenosis ### Why Transthoracic Echocardiography with Doppler is the Gold Standard **Key Point:** Transthoracic echocardiography (TTE) with Doppler is the first-line, non-invasive investigation of choice for diagnosis and assessment of mitral stenosis severity. **High-Yield:** TTE provides: - **Morphological assessment**: Leaflet thickening, commissural fusion, subvalvular apparatus involvement - **Hemodynamic data**: Mitral valve area (MVA) by planimetry or pressure half-time method - **Mean gradient**: Calculated from continuous-wave Doppler - **Associated findings**: Left atrial size, atrial fibrillation, left ventricular function, other valvular lesions ### Severity Grading by MVA | MVA (cm²) | Severity | |-----------|----------| | > 1.5 | Mild | | 1.0–1.5 | Moderate | | < 1.0 | Severe | **Clinical Pearl:** The opening snap (heard in this patient) indicates mobile anterior mitral leaflet — a favorable finding for percutaneous mitral commissurotomy (PMC), which is best assessed on echocardiography using the Wilkins score. ### When to Progress to Transesophageal Echocardiography (TEE) - Suboptimal transthoracic windows - Suspected thrombus in left atrium (before PMC) - Detailed assessment of subvalvular apparatus - Suspected endocarditis **Mnemonic:** **ECHO** = **E**chocardiography is **C**hoice for **H**emodynamic **O**utcome in MS. [cite:Harrison 21e Ch 282]