title: Diminished circadian variation in heart rate variability before surgery in patients developing postoperative atrial fibrillation.
abstract: OBJECTIVE
  To evaluate the role of the autonomic nervous system for the development of atrial fibrillation (AF) after coronary artery bypass surgery.
  
  
  METHODS
  Eighty patients without a previous history of AF were included. The sympathetic and parasympathetic activity were evaluated by the analysis of heart rate variability (HRV) in the frequency domain from 24-h Holter recordings and by measuring neuropeptides (neuropeptide Y, chromogranin A, chromogranin B, and pancreatic polypeptide (PP)) and catecholamines, obtained pre- and postoperatively.
  
  
  RESULTS
  Preoperatively, patients (36.3%) developing AF postoperatively showed a statistically significant less circadian variation in the HRV variables, the high-frequency (HF) component (p = 0.013) and the low-frequency (LF)/HF ratio (p = 0.007), than patients remaining in sinus rhythm. The HF component and PP. both reflecting parasympathetic activity, and all other variables in the frequency domain, decreased significantly after surgery in both patient groups (p < 0.0001). Although catecholamines increased significantly postoperatively in both patient groups, neither catecholamines nor neuropeptides expressing sympathetic activity, differed between the two groups. PP was, however, significantly higher in patients with postoperative AF than in those with sinus rhythm postoperatively on day 1.
  
  
  CONCLUSIONS
  The diminished circadian variation in HRV before surgery and the indirect signs of a higher parasympathetic activity in patients developing postoperative AF compared with patients remaining in sinus rhythm, may indicate a propensity for AF.
authors.affiliation: Department of Surgical Sciences, Thoracic and Cardiovascular Surgery, University Hospital, Uppsala, Sweden. lena.jideus@kirurgi.uu.se
authors.forename: L
authors.initials: L
authors.lastname: Jidéus
authors.forename: M
authors.initials: M
authors.lastname: Ericson
authors.forename: M
authors.initials: M
authors.lastname: Stridsberg
authors.forename: L
authors.initials: L
authors.lastname: Nilsson
authors.forename: P
authors.initials: P
authors.lastname: Blomström
authors.forename: C
authors.initials: C
authors.lastname: Blomström-Lundqvist
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood / Q000209:etiology / Q000503:physiopathology; D002395:Catecholamines / Q000097:blood; D002940:Circadian Rhythm / Q000502:physiology*; D001026:Coronary Artery Bypass; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009479:Neuropeptides / Q000097:blood; D015588:Observer Variation; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology / Q000503:physiopathology; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011300:Preoperative Care; D013548:Sweden / Q000453:epidemiology
chemical_list: D002395:Catecholamines; D009479:Neuropeptides