Question

Straightening of the left heart border with pulmonary congestion is seen on chest X-ray. What is the most likely diagnosis?

• A. Mitral stenosis
• B. Mitral regurgitation
• C. Aortic stenosis
• D. Tricuspid regurgitation

Hint:

CXR Signs of Mitral Stenosis:
- Straightening of the left heart border (Enlarged LA appendage).
- Double density sign on the right heart border (Enlarged LA pushing right).
- Splaying of the carina (angle $>$ 90 degrees due to enlarged LA pushing the left main bronchus upward).

Answer 1

The Correct Option is A

Concept:
The radiological evaluation of a chest X-ray in valvular heart disease relies on identifying specific alterations in the cardiac silhouette. Straightening of the left heart border is a pathognomonic sign of left atrial appendage enlargement.
Explanation:
• On a normal posteroanterior (PA) chest radiograph, the left heart border consists of three main bulges from superior to inferior: the aortic knuckle, the main pulmonary artery segment (forming the "pulmonary bay"), and the left ventricle.

• In Mitral Stenosis (MS), there is a mechanical obstruction to blood flow from the left atrium to the left ventricle. This leads to a significant increase in left atrial pressure and subsequent left atrial enlargement.

• As the left atrium dilates, its appendage enlarges and bulges outward, filling the normal concavity of the pulmonary bay. This gives the left heart border a flat or "straightened" appearance.

• Additionally, the elevated left atrial pressure is transmitted retrogradely into the pulmonary venous system, resulting in pulmonary congestion (manifesting as cephalization of vessels and Kerley B lines).

• Mitral Regurgitation (Option B) typically causes massive enlargement of the left atrium and left ventricle (cardiomegaly), rather than just the isolated straightening seen in early to moderate MS.

• Aortic Stenosis (Option C) classically presents with a rounded left ventricular apex due to concentric hypertrophy and post-stenotic aortic dilatation, not left atrial appendage bulging.
Final Answer:
The combination of a straightened left heart border (due to left atrial appendage enlargement) and pulmonary congestion is the classical radiological hallmark of Mitral Stenosis.