I23.5

HCC Category Mapping

What This Code Means

This code describes a tear or break in the papillary muscle (a small muscle in the heart that helps control the heart valve) that occurs 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 is specifically for papillary muscle rupture occurring as a current complication of acute MI; ensure the rupture is documented as occurring during the acute phase (typically within 4 weeks post-MI)
• •Do not use this code if the papillary muscle rupture is a late complication or sequela of a previous MI; instead use the appropriate sequela code from category I25

Clinical Significance

Rupture of the papillary muscle following acute myocardial infarction is one of the most lethal mechanical complications, causing acute severe mitral regurgitation and rapid hemodynamic collapse. The posteromedial papillary muscle is most commonly affected because it has a single blood supply from the posterior descending artery, unlike the anterolateral papillary muscle which has dual blood supply. Without emergent surgical intervention, mortality approaches 100%.

Documentation Requirements

• ✓Documentation of papillary muscle rupture as a current complication of acute myocardial infarction
• ✓Echocardiographic or surgical confirmation showing papillary muscle rupture with flail leaflet
• ✓Timing within the acute phase (typically 2-7 days post-myocardial infarction)
• ✓Documentation of which papillary muscle is involved (posteromedial or anterolateral) if specified
• ✓Severity of mitral regurgitation
• ✓The underlying acute myocardial infarction coded separately (I21.x)
• ✓Treatment plan (emergent surgical repair/replacement)

Commonly Confused Codes