title: Intracardiac and extracardiac markers of inflammation during atrial fibrillation.
abstract: BACKGROUND
  A decrease in inflammation after cure of atrial arrhythmias suggests that such arrhythmias are proinflammatory, and lower inflammatory marker levels in the coronary sinus suggest that atrial arrhythmias result in intracardiac appropriation of inflammatory cytokines.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the effect of atrial fibrillation on inflammatory markers drawn from intracardiac and extracardiac chambers.
  
  
  METHODS
  We performed a case-control study of 167 AF patients and 207 controls. Blood from intracardiac and extracardiac sites was obtained from a subset of patients undergoing curative AF ablation (n = 46).
  
  
  RESULTS
  No significant differences in C-reactive protein (CRP) or interleukin-6 (IL-6) levels were seen between patients with and those without a history of AF. Both levels were significantly higher when blood was drawn during AF than during sinus rhythm: median CRP 3.1 mg/dL (interquartile range [IQR] 1.0-6.0) versus 1.7 mg/dL (IQR 0.7-3.9, P = .0005); median IL-6 2.3 ng/mL (IQR 1.5-3.9) versus 1.5 ng/mL (IQR 0.7-2.5, P = .007). This finding persisted after adjusting for potential confounders. AF ablation patients in AF exhibited a positive median left atrial minus coronary sinus gradient CRP (0.3 mg/dL, IQR -0.03-1.1), whereas those in sinus rhythm had a negative median left atrial minus coronary sinus gradient CRP (-0.2, IQR -0.8-[-0.02], P = .01). Femoral artery minus femoral vein gradients in AF versus sinus rhythm did not show any differences.
  
  
  CONCLUSIONS
  AF at the time of the blood draw, rather than a history of AF, was independently associated with inflammation. Differences in transcardiac gradients suggest that AF results in sequestration of inflammatory cytokines in the heart.
authors.affiliation: Division of Cardiology, University of California, San Francisco, CA, USA. marcusg@medicine.ucsf.edu
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Marcus
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Smith
authors.forename: Karen
authors.initials: K
authors.lastname: Ordovas
authors.forename: Melvin M
authors.initials: MM
authors.lastname: Scheinman
authors.forename: Albert M
authors.initials: AM
authors.lastname: Kim
authors.forename: Nitish
authors.initials: N
authors.lastname: Badhwar
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Lee
authors.forename: Zian H
authors.initials: ZH
authors.lastname: Tseng
authors.forename: Byron K
authors.initials: BK
authors.lastname: Lee
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Olgin
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood* / Q000628:therapy; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015897:Comorbidity; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D002097:C-Reactive Protein