title: Mitral apparatus assessment by delayed enhancement CMR: relative impact of infarct distribution on mitral regurgitation.
abstract: OBJECTIVE
  This study sought to assess patterns and functional consequences of mitral apparatus infarction after acute myocardial infarction (AMI).
  
  
  BACKGROUND
  The mitral apparatus contains 2 myocardial components: papillary muscles and the adjacent left ventricular (LV) wall. Delayed-enhancement cardiac magnetic resonance (DE-CMR) enables in vivo study of inter-relationships and potential contributions of LV wall and papillary muscle infarction (PMI) to mitral regurgitation (MR).
  
  
  METHODS
  Multimodality imaging was performed: CMR was used to assess mitral geometry and infarct pattern, including 3D DE-CMR for PMI. Echocardiography was used to measure MR. Imaging occurred 27 ± 8 days after AMI (CMR, echocardiography within 1 day).
  
  
  RESULTS
  A total of 153 patients with first AMI were studied; PMI was present in 30% (n = 46 [72% posteromedial, 39% anterolateral]). When stratified by angiographic culprit vessel, PMI occurred in 65% of patients with left circumflex, 48% with right coronary, and only 14% of patients with left anterior descending infarctions (p <0.001). Patients with PMI had more advanced remodeling as measured by LV size and mitral annular diameter (p <0.05). Increased extent of PMI was accompanied by a stepwise increase in mean infarct transmurality within regional LV segments underlying each papillary muscle (p <0.001). Prevalence of lateral wall infarction was 3-fold higher among patients with PMI compared to patients without PMI (65% vs. 22%, p <0.001). Infarct distribution also impacted MR, with greater MR among patients with lateral wall infarction (p = 0.002). Conversely, MR severity did not differ on the basis of presence (p = 0.19) or extent (p = 0.12) of PMI, or by angiographic culprit vessel. In multivariable analysis, lateral wall infarct size (odds ratio 1.20/% LV myocardium [95% confidence interval: 1.05 to 1.39], p = 0.01) was independently associated with substantial (moderate or greater) MR even after controlling for mitral annular (odds ratio 1.22/mm [1.04 to 1.43], p = 0.01), and LV end-diastolic diameter (odds ratio 1.11/mm [0.99 to 1.23], p = 0.056).
  
  
  CONCLUSIONS
  Papillary muscle infarction is common after AMI, affecting nearly one-third of patients. Extent of PMI parallels adjacent LV wall injury, with lateral infarction-rather than PMI-associated with increased severity of post-AMI MR.
authors.affiliation: Department of Medicine, Greenberg Cardiology Division, Weill Cornell Medical College, New York, New York 10021, USA.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Chinitz
authors.forename: Debbie
authors.initials: D
authors.lastname: Chen
authors.forename: Parag
authors.initials: P
authors.lastname: Goyal
authors.forename: Sean
authors.initials: S
authors.lastname: Wilson
authors.forename: Fahmida
authors.initials: F
authors.lastname: Islam
authors.forename: Thanh
authors.initials: T
authors.lastname: Nguyen
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Sandra
authors.initials: S
authors.lastname: Hurtado-Rua
authors.forename: Lauren
authors.initials: L
authors.lastname: Simprini
authors.forename: Matthew
authors.initials: M
authors.lastname: Cham
authors.forename: Robert A
authors.initials: RA
authors.lastname: Levine
authors.forename: Richard B
authors.initials: RB
authors.lastname: Devereux
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Weinsaft
mesh_terms: D000328:Adult; D000368:Aged; D056988:Anterior Wall Myocardial Infarction / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D016009:Chi-Square Distribution; D003287:Contrast Media; D018618:Echocardiography, Doppler, Color; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D006801:Humans; D056989:Inferior Wall Myocardial Infarction / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D016015:Logistic Models; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000473:pathology*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D015999:Multivariate Analysis; D009206:Myocardium / Q000473:pathology*; D016017:Odds Ratio; D010210:Papillary Muscles / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors
chemical_list: D003287:Contrast Media