Nonrheumatic mitral (valve) prolapse

This code represents a condition where the mitral valve leaflets bulge (prolapse) into the left atrium during ventricular contraction, but it is not caused by rheumatic fever. This structural abnormality can lead to mitral regurgitation, where blood leaks backward through the valve.

Assign this code when documentation explicitly states "nonrheumatic mitral valve prolapse" or "mitral prolapse" without an underlying rheumatic etiology. This diagnosis is typically made via echocardiography, which identifies the characteristic leaflet displacement.

• Do not use this code if Marfan's syndrome is documented as the cause; refer to the Excludes1 note.
• Specify any associated mitral regurgitation with an additional code (e.g., I34.0).
• Ensure the documentation clearly differentiates from rheumatic mitral valve disease (I05.-).