Question: what can mitral valve regurgitation cause?
Answer: Mitral valve prolapse. In this condition, the mitral valve's leaflets bulge back into the left atrium during the heart's contraction. ... 
Damaged tissue cords. ... 
Rheumatic fever. ... 
Endocarditis. ... 
Heart attack. ... 
Abnormality of the heart muscle (cardiomyopathy). ... 
Trauma. ... 
Congenital heart defects.