Mitral valve regurgitation is caused by:

• A. Myxomatous changes in the mitral valve.
• B. Bacterial infection of the tricuspid valve.
• C. Calcification of the aortic valve.
• D. Inflammation of the pericardium.

Answer: (A)

Mitral valve regurgitation arises when the valve can’t close properly during systole, allowing blood to leak back from the left ventricle into the left atrium. Myxomatous changes in the mitral valve tissue produce floppy, elongated leaflets and chordae tendineae, so the leaflets don’t coapt (seal) well and may prolapse into the atrium. This structural degeneration directly undermines closure, making regurgitation more likely. The other options involve problems affecting other structures or conditions that don’t directly cause mitral valve leakage: infection of the tricuspid valve would impact the tricuspid valve (not the mitral), calcification of the aortic valve affects the aortic valve, and pericardial inflammation involves the sac around the heart rather than the valve apparatus. So the degenerative, myxomatous change of the mitral valve is the most direct and common cause of mitral regurgitation.