title: Atrial fibrillation is associated with increased neurohumoral activation and reduced exercise tolerance in patients with non-ischemic dilated cardiomyopathy.
abstract: OBJECTIVE
  To assess atrial fibrillation (AF) associated differences in proinflammatory cytokines, natriuretic peptide levels and exercise capacity in patients with heart failure (HF) secondary to non-ischemic dilated cardiomyopathy (NIDC).
  
  
  METHODS
  We studied 147 NIDC patients, mean age 58.3+/-12.5 years, left ventricular (LV) ejection fraction 27.8+/-10.9% and NYHA class II-III. Neurohumoral activation was assessed by measurement of interleukin IL-1, IL-6, tumor necrosis factor-a (TNF-a), its soluble receptors sTNFR I and II, N-terminal atrial (NT-ANP) and -brain (NT-BNP) natriuretic peptide levels, and functional class was assessed by cardiopulmonary exercise test.
  
  
  RESULTS
  Forty patients (27.5%) had chronic AF and they did not differ in age, LV ejection fraction or HF duration compared to patients in sinus rhythm (SR). AF was associated with increased levels of IL-6 (p=0.001), TNF-a (p=0.002), sTNFRI (p=0.023), NT-ANP (p<0.001) and NT-BNP (p=0.003), decreased exercise duration (p<0.001) and slightly reduced maximal oxygen consumption at peak exercise (p=0.07) compared to SR patients. No significant differences in cytokine and natriuretic peptide levels or exercise tolerance were noted when patients in AF were compared to the subgroup of SR with restrictive LV filling pattern. Multivariate analysis showed that NT-ANP (p=0.003) and IL-6 (p=0.006) plasma levels were independently associated with the presence of AF in our patient population.
  
  
  CONCLUSIONS
  AF is associated with increased inflammatory state, natriuretic peptide levels and reduced exercise capacity in patients with HF secondary to NIDC. These findings suggest that the presence of AF in HF represents a more advanced stage of the syndrome.
authors.affiliation: Department of Cardiology, Heraklion University Hospital, Crete, Greece. fparth@med.uoc.gr
authors.forename: Frangiskos I
authors.initials: FI
authors.lastname: Parthenakis
authors.forename: Alexandros P
authors.initials: AP
authors.lastname: Patrianakos
authors.forename: Emmanuel I
authors.initials: EI
authors.lastname: Skalidis
authors.forename: George F
authors.initials: GF
authors.lastname: Diakakis
authors.forename: Evangelos A
authors.initials: EA
authors.lastname: Zacharis
authors.forename: Gregory
authors.initials: G
authors.lastname: Chlouverakis
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Karalis
authors.forename: Panos E
authors.initials: PE
authors.lastname: Vardas
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood* / Q000209:etiology*; D002311:Cardiomyopathy, Dilated / Q000150:complications* / Q000000981:diagnostic imaging; D002908:Chronic Disease; D016207:Cytokines / Q000097:blood; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000209:etiology* / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D045265:Natriuretic Peptides / Q000097:blood; D018377:Neurotransmitter Agents / Q000097:blood*; D010101:Oxygen Consumption; D014463:Ultrasonography; D016277:Ventricular Function, Left
chemical_list: D016207:Cytokines; D045265:Natriuretic Peptides; D018377:Neurotransmitter Agents