ICD-10 Code 242.1: Secondary Mitral Valve Insufficiency – Clinical Context

ICD-10-CM code I05.1 (not 242.1, which is an ICD-9 legacy code) classifies Rheumatic mitral insufficiency. The description “Secondary mitral valve insufficiency” typically maps to I34.0 (Nonrheumatic mitral insufficiency) when due to non-rheumatic causes (e.g., ischemic cardiomyopathy, dilated cardiomyopathy, papillary muscle dysfunction).

Clinical Definition

Mitral regurgitation (insufficiency) is backward flow from left ventricle to left atrium during systole due to incomplete valve closure. “Secondary” (functional) MR results from ventricular remodeling—not primary valve pathology—causing annular dilation and leaflet tethering.

Coding Guidance

• Use I05.1 if rheumatic etiology documented.
• Use I34.0 for nonrheumatic (functional/degenerative) MR.
• Code underlying cause (e.g., I25.5 ischemic cardiomyopathy) also.

Note: ICD-9 code 242.1 is obsolete (ICD-9 retired 2015). Always use current ICD-10-CM.