Importance of papillary muscle infarction detected by cardiac magnetic resonance imaging in predicting cardiovascular events

Background: Recent studies suggest that papillary muscle infarction (PMI) following recent myocardial infarction (MI) correlates with adverse cardiovascular outcomes. The purpose of this study is to determine the prevalence and prognostic significance of PMI by cardiac magnetic resonance (CMR) in a large cohort of patients.

Methods: Retrospective study of patients who underwent CMR between January 2007 and December 2009 were evaluated for the presence of PMI in one or both of the left ventricle papillary muscles. The primary outcome was a time to a combined endpoint of all-cause mortality and worsening heart failure. Secondary outcomes were time to individual components of the combined outcome.

Results: 419 patients were included in our analysis, 232 patients (55%) had ischemic cardiomyopathy. Patients were followed at six-month intervals for a median follow-up time of 3.7 (interquartile range (IQR): 1.6; 6.3) years after initial imaging. During this period 196 patients (46.8%) had a primary outcome and 92 patients (22%) died. PM infarct was identified in 204 (48.7%) patients with twice as many posteromedial (PRM) (27%) than anterolateral (ARL) lesions (11%) and a similar number with infarct in both (11%). There was no association between studied outcomes and the presence of PMI in either PRM or ARL PM. The presence of infarct in both PM was a predictor of both the primary outcome (HR 1.69, CI[1.01-2.86], p<0.049.) and mortality (HR 1.69, CI[1.01-4.2], p<0.046).

Conclusion: The presence of infarct in either papillary muscle was not associated with outcomes. However, infarct involving both papillary muscles was associated with worse outcomes.