Nonrheumatic mitral (valve) insufficiency

This code represents the backward flow of blood through the mitral valve into the left atrium during ventricular systole, not caused by rheumatic fever. It signifies a structural or functional defect of the mitral valve leading to its incomplete closure.

Use this code for documented cases of mitral regurgitation where the etiology is explicitly stated as nonrheumatic. This includes degenerative mitral valve disease, mitral valve prolapse with regurgitation, or ischemic mitral regurgitation. Documentation should clearly specify "nonrheumatic" or provide an alternative non-rheumatic cause.

• Differentiate carefully between rheumatic and nonrheumatic etiologies; if rheumatic, a code from I05.1 should be used.
• Always look for documentation of the severity (e.g., mild, moderate, severe) as this may impact treatment but does not change the primary diagnosis code.
• If mitral valve prolapse is also documented as the cause, code I34.1 (Nonrheumatic mitral valve prolapse) should be sequenced first, followed by this code.