title: Prevalence and clinical significance of papillary muscle infarction detected by late gadolinium-enhanced magnetic resonance imaging in patients with ST-segment elevation myocardial infarction.
abstract: BACKGROUND
  The frequency of papillary muscle infarction (PapMI) without rupture has not been fully investigated in vivo. Furthermore, the relationship between papillary muscle dysfunction and mitral regurgitation (MR) has been controversial in patients with ST-segment elevation myocardial infarction. Therefore, the aim of this study was to assess the frequency and clinical characteristics of PapMI without rupture using late gadolinium-enhanced magnetic resonance imaging (MRI) in patients with ST-segment elevation myocardial infarction.
  
  
  RESULTS
  One hundred eighteen ST-segment elevation myocardial infarction patients with primary percutaneous coronary intervention underwent cardiac MRI twice 9±4 days and 8±1 months (n=104) after myocardial infarction. MR was categorized by echocardiography. Of these patients, 40% were found to have late gadolinium enhancement of papillary muscle, in which the posterior papillary muscle was involved more frequently than the anterior papillary muscle (77% versus 26%; P<0.001). PapMI was encountered more frequently in patients with left circumflex and right coronary artery lesions compared with left anterior descending artery lesion (78%, 48%, and 13%; P<0.001). By multiple logistic regression analysis, only coaptation height was identified as an independent predictor of the presence of MR. The second cardiac magnetic resonance imaging showed that the infarct size had a positive correlation with left ventricular end-diastolic volume (r=0.41, P<0.001) and that PapMI was not associated with left ventricular remodeling (P=0.31). Deterioration of MR was not observed in patients with PapMI.
  
  
  CONCLUSIONS
  PapMI is more frequent than previously thought yet appears to have significant clinical latency. The size of the myocardial infarction, but not the presence of PapMI, seems to affect left ventricular remodeling, and PapMI is not obligatorily associated with MR.
authors.affiliation: Department of Cardiovascular Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tanimoto
authors.forename: Toshio
authors.initials: T
authors.lastname: Imanishi
authors.forename: Hironori
authors.initials: H
authors.lastname: Kitabata
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nakamura
authors.forename: Keizo
authors.initials: K
authors.lastname: Kimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamano
authors.forename: Kohei
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Komukai
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ino
authors.forename: Shigeho
authors.initials: S
authors.lastname: Takarada
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubo
authors.forename: Kumiko
authors.initials: K
authors.lastname: Hirata
authors.forename: Masato
authors.initials: M
authors.lastname: Mizukoshi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Akasaka
mesh_terms: D000368:Aged; D003331:Coronary Vessels / Q000473:pathology / Q000503:physiopathology; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D005682:Gadolinium; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007238:Infarction / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology*; D010210:Papillary Muscles / Q000473:pathology / Q000503:physiopathology*; D015995:Prevalence; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D005682:Gadolinium