Prevalence and prognostic value of papillary muscle infarction in patients with previous myocardial infarction

Objective: To determine the prevalence and prognostic value of papillary muscle infarction. Materials and Methods: The authors studied patients who were referred for cardiac magnetic resonance [CMR] for assessment of myocardial ischemia or myocardial viability and found to have previous myocardial infarction. CMR was performed for assessment of cardiac function and late gadolinium enhancement [LGE], including detection and quantification of mitral regurgitation. Patients were followed for cardiac events, including cardiac death, nonfatal myocardial infarction, and hospitalization due to heart failure. Results: The authors studied 785 patients with previous myocardial infarction. Average age was 64.8 years. Papillary muscle infarction was found in 305 patients (38.9%). Papillary muscle infarction was associated with an increase in left ventricular volumes, mass, wall motion score, LGE percentages, and mitral regurgitation. Patients with papillary muscle infarction had increased risk of cardiac event during follow-up. Multivariable analysis showed that left ventricular end-systolic volume index and mitral regurgitation were independent predictors for cardiac event. Conclusion: Papillary muscle infarction is not an uncommon condition. It was found to be associated with more severe left ventricular dysfunction. The increased risk associated with papillary muscle infarction was mediated by more severe myocardial damage and mitral regurgitation.