Impact of papillary muscle infarction on ischemic mitral regurgitation assessed by magnetic resonance imaging

Objective Ischemic mitral regurgitation is a predictor of heart failure resulting in increased mortality in patients with chronic myocardial infarction. It is uncertain whether the presence of papillary muscle (PM) infarction contributes to the development of mitral regurgitation in patients with chronic myocardial infarction (MI). The aim of the present study was to assess the correlation of PM infarction depicted by MRI with mitral regurgitation and left ventricular function. 48 patients with chronic MI and recent MRI and echocardiography were retrospectively included. The location and extent of MI depicted by MRI were correlated with left ventricular function assessed by MRI and mitral regurgitation assessed by echocardiography. The presence, location and extent of PM infarction depicted by late gadolinium enhancement (LGE-) MRI were correlated with functional parameters and compared with patients with chronic MI but no PM involvement. PM infarction was found in 11 of 48 patients (23 %) using LGE-MRI. 8/11 patients (73 %) with PM infarction and 22/37 patients (59 %) without PM involvement in MI had ischemic mitral regurgitation. There was no significant difference between location, extent of MI and presence of mitral regurgitation between patients with and without PM involvement in myocardial infarction. In 4/4 patients with complete and in 4/7 patients with partial PM infarction, mitral regurgitation was present. The normalized mean left ventricular end-diastolic volume was increased in patients with ischemic mitral regurgitation. The presence of PM infarction does not correlate with ischemic mitral regurgitation. In patients with complete PM infarction and consequent discontinuity of viable tissue in the PM-chorda-mitral valve complex, the probability of developing ischemic mitral regurgitation seems to be increased. However, the severity of mitral regurgitation is not increased compared to patients with partial or no PM infarction.