I23.4

HCC Category Mapping

What This Code Means

This code describes a tear or breaking of the heart strings (chordae tendineae) that support the heart valves, occurring as a direct complication shortly after a heart attack. This is a serious condition that can cause the heart valve to leak and lead to heart failure.

Coding Tips

• •This code requires documentation of both the acute myocardial infarction (MI) and the chordae tendineae rupture as a current complication; code the MI separately using the appropriate I21.x code
• •The timeframe for 'current complication' is typically within 28 days of the acute MI; verify documentation clearly establishes this temporal relationship

Clinical Significance

Rupture of chordae tendineae following acute myocardial infarction is a mechanical complication that causes acute mitral regurgitation, which can lead to rapid heart failure and cardiogenic shock. The chordae tendineae are the fibrous cords that anchor the mitral valve leaflets to the papillary muscles, and their rupture due to ischemic necrosis results in flail mitral valve leaflet. This is a surgical emergency requiring urgent valve repair or replacement.

Documentation Requirements

• ✓Documentation of chordae tendineae rupture as a current complication of acute myocardial infarction
• ✓Echocardiographic confirmation showing flail leaflet and severe mitral regurgitation
• ✓Temporal relationship within the acute phase (typically within 28 days of the myocardial infarction)
• ✓The underlying acute myocardial infarction coded separately (I21.x)
• ✓Hemodynamic assessment and treatment plan
• ✓Degree of mitral regurgitation documented

Commonly Confused Codes