title: Serum YKL-40 as a Marker of Left Atrial Fibrosis Assessed by Delayed Enhancement MRI in Lone Atrial Fibrillation.
abstract: BACKGROUND
  Assessment of the left atrial (LA) fibrosis by using delayed-enhanced magnetic resonance imaging (DE-MRI) in atrial fibrillation (AF) patients is a pioneering noninvasive method. Serum YKL-40 is a novel marker for inflammation and known to play a role in ongoing tissue fibrosis. However, its role in LA fibrosis is unclear. We aimed to investigate the association of serum YKL-40 with the presence and extent of LA fibrosis.
  
  
  METHODS
  A total of 50 patients with lone paroxysmal AF (62% male; age: 47.2 ± 7.0 years) underwent cardiac DE-MRI according to study protocol. Cardiac DE-MRI at 1.5 Tesla scanner was used to quantify LA fibrosis. Serum YKL-40 levels and clinical and echocardiographic data were recorded in all participants.
  
  
  RESULTS
  DE-MRI revealed any degree of LA fibrosis in 31 (62%) patients. Median serum YKL-40 was significantly higher (P = 0.008) and left venticular ejection fraction was lower (P = 0.047) in patients with LA fibrosis as compared to patients without LA fibrosis. Extent of LA fibrosis was significantly correlated with age, duration of AF history, serum C-reactive protein, and serum YKL-40 levels. Only log (YKL-40) level was found as independent predictor for the presence of LA fibrosis (odds ratio: 1.626, P = 0.022). Multivariate linear regression analysis pointed out that duration of AF history (β = 0.330, P = 0.003) and serum log (YKL-40) levels (β = 0.546, P < 0.001) were significantly and independently associated with the extent of LA fibrosis.
  
  
  CONCLUSIONS
  Higher levels of serum YKL-40 are associated with the presence and more extensive LA fibrosis in patients with lone AF. As a marker of inflammation, serum YKL-40 may also be used as an indicator for the degree of LA fibrosis.
authors.affiliation: Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Uğur
authors.initials: U
authors.lastname: Canpolat
authors.affiliation: Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Kudret
authors.initials: K
authors.lastname: Aytemir
authors.affiliation: Department of Radiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Tuncay
authors.initials: T
authors.lastname: Hazirolan
authors.affiliation: Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Necla
authors.initials: N
authors.lastname: Özer
authors.affiliation: Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Oto
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood* / Q000150:complications / Q000473:pathology*; D015415:Biomarkers / Q000097:blood; D000071451:Chitinase-3-Like Protein 1 / Q000097:blood*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005355:Fibrosis; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D003287:Contrast Media
keywords: YKL-40; atrial fibrillation; atrial fibrosis; magnetic resonance imaging