title: Low preoperative HSP70 atrial myocardial levels correlate significantly with high incidence of postoperative atrial fibrillation after cardiac surgery.
abstract: OBJECTIVE
  Atrial fibrillation after cardiac surgery is still a frequent encountered complication and has been associated with increased hospital length of stay and numerous postoperative complications. The pathogenesis of atrial fibrillation involves an overall sequence of perioperative events, collectively termed as ischemia-reperfusion injury. Heat-shock proteins have been found to provide increased protection during ischemia-reperfusion as well as increased postischemic cardiac functional recovery. We sought to determine whether preoperative atrial heat shock levels were correlated with the appearance of postoperative atrial fibrillation.
  
  
  METHODS
  Preoperative atrial myocardial samples obtained just before cannulation from 101 patients were used to detect immunohistochemically the expression of heat-shock proteins. The derived results were compared statistically with the incidence of postoperative atrial fibrillation, its time of appearance, duration and resistance to administered antiarrhythmics.
  
  
  RESULTS
  The overall incidence of postoperative atrial fibrillation was 22.3%. Of these patients, 58.3% had no detectable heat shock proteins in their cytoplasm, in sharp contrast with 100% of the patients with no atrial fibrillation who were positive for heat shock proteins (p<0.01). Four percent of our patient group had prolonged atrial fibrillation (defined as duration >48 h). These patients had significantly less (p<0.01) nuclear heat shock protein expression compared with the non-atrial fibrillation group. However, the difference of the heat shock protein expression between the prolonged atrial fibrillation and the rest of the atrial fibrillation patients was not significant (p=0.891).
  
  
  CONCLUSIONS
  Our results indicate that patients with low preoperative atrial heat shock protein expression have a significantly greater incidence of postoperative atrial fibrillation. Heat shock protein expression did not, however, correlate with the onset of atrial fibrillation and the resistance to administered medications. Heat shock protein preoperative induction as a measure of myocardial preconditioning may potentially decrease the incidence of postoperative atrial fibrillation.
authors.affiliation: Cardiothoracic Surgery, AHEPA General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece. rammos@the.forthnet.gr
authors.forename: Kyriakos
authors.initials: K
authors.lastname: St Rammos
authors.forename: George J
authors.initials: GJ
authors.lastname: Koullias
authors.forename: Moustafa O
authors.initials: MO
authors.lastname: Hassan
authors.forename: Nikolaos P
authors.initials: NP
authors.lastname: Argyrakis
authors.forename: Christos G
authors.initials: CG
authors.lastname: Voucharas
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Scarupa
authors.forename: Tomas G
authors.initials: TG
authors.lastname: Cowte
mesh_terms: D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology / Q000209:etiology*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D002317:Cardiovascular Agents / Q000627:therapeutic use; D004351:Drug Resistance; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis*; D006325:Heart Atria / Q000737:chemistry; D006801:Humans; D015994:Incidence; D008297:Male; D009206:Myocardium / Q000737:chemistry*; D011183:Postoperative Complications / Q000453:epidemiology; D011300:Preoperative Care
chemical_list: D002317:Cardiovascular Agents; D018840:HSP70 Heat-Shock Proteins