Which of the following is NOT listed as a cause of chronic MR?

• A. Rheumatic heart disease
• B. Cleft mitral valve
• C. MAC
• D. Aortic stenosis

Answer: (D)

Chronic mitral regurgitation mainly arises from problems with the mitral valve itself or from changes in the left ventricle that prevent proper leaflet closure. Rheumatic heart disease damages the leaflets and chordae, leading to chronic MR. A cleft mitral valve is a congenital abnormality that creates a regurgitant orifice. Mitral annular calcification distorts the ring around the valve, causing incomplete coaptation and MR over time. Aortic stenosis, on the other hand, is a disease of the aortic valve. It does not directly cause chronic MR, though severe LV changes from any valve disease can sometimes contribute to functional MR. Therefore, the option that is not a listed cause is aortic stenosis.