A mid diastolic rumbling murmur at the left lower sternal border with an opening snap is most consistent with which lesion?

• A. Mitral Stenosis
• B. Pulmonary Stenosis
• C. Tricuspid Regurgitation
• D. Tricuspid Stenosis

Answer: (D)

A diastolic rumble heard at the left lower sternal border with an opening snap is classic for tricuspid stenosis. The mid-diastolic murmur arises from turbulent flow across a narrowed tricuspid valve during diastole, and the opening snap happens as the stiff valve leaflets are finally forced open by atrial pressure in early to mid-diastole. The left lower sternal border location aligns with the tricuspid valve area. By contrast, mitral stenosis produces a similar opening snap and diastolic rumble at the apex, pulmonary stenosis presents a systolic murmur at the left upper sternal border, and tricuspid regurgitation is a holosystolic murmur at the left lower sternal border. Therefore this pattern best fits tricuspid stenosis.