Mitral regurgitation can lead to backward flow of blood between which chambers?

• A. Backflow of blood from the left atrium to the left ventricle
• B. Backflow of blood from the right ventricle to the right atrium
• C. Obstruction of the mitral valve
• D. Backflow of blood from the left ventricle to the left atrium through the mitral valve, with left atrial dilation and possible pulmonary edema

Answer: (D)

Mitral regurgitation involves the mitral valve not closing properly during systole, so blood leaks backward from the left ventricle into the left atrium. This creates a volume overload in the left atrium, causing it to enlarge, and the elevated pressure can push fluid back into the lungs, potentially causing pulmonary edema. So the backward flow is from the left ventricle to the left atrium through the mitral valve, with left atrial dilation and possible pulmonary edema.

The other ideas don’t fit: backflow from the left atrium to the left ventricle would be abnormal direction for regurgitation and isn’t how the mitral valve leaks. Backflow between the right-sided chambers involves the tricuspid valve, not the mitral. Obstruction of the mitral valve describes stenosis, not regurgitation.