title: Activation of coagulation occurs after electrical cardioversion in patients with chronic atrial fibrillation despite optimal anticoagulation with warfarin.
abstract: BACKGROUND
  There is evidence for the activation of the coagulation system and a hypercoagulable state following cardioversion. The aim of the study was to determine whether electrical cardioversion in patients with chronic atrial fibrillation induced a prothrombotic state despite optimal anticoagulation. We studied the effects of electrical cardioversion on plasma levels of fibrinogen, antithrombin III, protein C and D-dimers.
  
  
  METHODS
  We studied 24 patients with chronic atrial fibrillation who were on optimal anticoagulation and were referred for electrical cardioversion. Samples of venous blood were taken 2 h pre and post cardioversion and 1 month later.
  
  
  RESULTS
  Plasma median concentrations of fibrinogen decreased significantly from 3.8 g/l (interquartile range 3.1-4.2 g/l) before cardioversion to 3.5 g/l (interquartile range 2.9-3.9 g/l) 2 h after cardioversion levels (P=0.004). The fibrinogen levels at 1 month post cardioversion (3.45 g/l, interquartile range 3.1-3.9 g/l) were also significantly lower than baseline (P=0.02). Plasma median levels of antithrombin III fell from 93.5 U/dl (interquartile range 89.3-97.0 U/dl) pre cardioversion to 89.5 U/dl (interquartile range 83.0-93.0 U/dl) 2 h after cardioversion (P=0.001) and returned to normal by 1 month (94.0 U/dl; interquartile range 89.3-98.5 U/dl; P=0.0001). There were no significant changes in plasma median D-dimer or protein C levels at any time.
  
  
  CONCLUSIONS
  We have demonstrated a significant fall in the plasma fibrinogen and antithrombin III levels in patients with chronic atrial fibrillation early after electrical cardioversion, indicating thrombin generation. This study suggests that there are haemostatic changes of thrombogenesis induced by cardioversion despite optimal anticoagulation with warfarin.
authors.affiliation: Department of Medicine, Derriford Hospital, Plymouth PL6 8DH, UK. kjacob@doctors.org.uk
authors.forename: Koshy
authors.initials: K
authors.lastname: Jacob
authors.forename: Suneel
authors.initials: S
authors.lastname: Talwar
authors.forename: Adrian
authors.initials: A
authors.lastname: Copplestone
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Gilbert
authors.forename: Guy A
authors.initials: GA
authors.lastname: Haywood
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D000990:Antithrombin III / Q000187:drug effects / Q000378:metabolism; D001281:Atrial Fibrillation / Q000097:blood* / Q000628:therapy*; D015415:Biomarkers / Q000097:blood; D001777:Blood Coagulation / Q000187:drug effects*; D002908:Chronic Disease; D004554:Electric Countershock; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000187:drug effects / Q000378:metabolism; D005340:Fibrinogen / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011486:Protein C / Q000187:drug effects / Q000378:metabolism; D016896:Treatment Outcome; D006113:United Kingdom; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; D011486:Protein C; C036309:fibrin fragment D; D014859:Warfarin; D000990:Antithrombin III; D005340:Fibrinogen