A 62-year-old man with severe chronic aortic regurgitation has a soft mid-diastolic rumble at the apex. Which finding best supports that this rumble is an Austin Flint murmur rather than coexisting mitral stenosis?

• A Presystolic accentuation of the rumble
• B Accentuation of the rumble after amyl nitrite inhalation
• C Loud second heart sound with fixed splitting
• D Normal intensity first heart sound with no opening snap ✓

Explanation

The Austin Flint murmur of severe aortic regurgitation mimics mitral stenosis because the AR jet strikes the anterior mitral leaflet, but the mitral valve itself is structurally normal, so S1 remains soft or normal and there is no opening snap. In true mitral stenosis, S1 is loud and an opening snap follows A2. Amyl nitrite increases the AR jet volume and thus intensifies the Austin Flint murmur, whereas it softens a genuine mitral stenosis flow murmur.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.