title: Poor anticoagulation relates to extended access times for cardioversion and is associated with long-term major cardiac and cerebrovascular events.
abstract: BACKGROUND
  Patients undergoing elective electrical cardioversion (ECV) for atrial fibrillation have a temporarily increased risk of thromboembolism. Current guidelines recommend adequate anticoagulation for ≥3 consecutive weeks precardioversion, i.e. consecutive INR values 2.0-3.0 in patients with vitamin K antagonists (VKA). We aimed to evaluate the occurrence and impact of subtherapeutic INRs precardioversion and to study factors associated with these unwanted fluctuations.
  
  
  METHODS
  We recruited 346 consecutive patients undergoing elective ECV in the Maastricht University Medical Centre between 2008 and 2013. Predictors of subtherapeutic INR values were identified and incorporated into a logistic regression model.
  
  
  RESULTS
  A subtherapeutic INR precardioversion occurred in 55.2% of patients. The only statistically significant predictor was VKA-naivety (Odds Ratio (OR) 4.78, 95% Confidence Interval (CI) 2.67-8.58, p<0.001). In patients with ≥1 subtherapeutic INR precardioversion, time from referral until cardioversion was 91.1±42.8days, compared to 41.7±26.6days (p<0.001) in patients without subtherapeutic INRs. No thromboembolic events occurred <30days after the ECV. Independent predictors for the combined endpoint of cardiovascular death, ischemic stroke and the need of blood transfusion (n=30, median follow-up of 374days) were coronary artery disease in the history (OR 3.35, 95%CI 1.54-7.25, p=0.002) and subtherapeutic INR precardioversion (OR 3.64, 95%CI 1.43-9.24, p=0.007).
  
  
  CONCLUSIONS
  The use of VKA often results in subtherapeutic INRs precardioversion and is associated with a significant delay until cardioversion, especially in patients with recent initiation of VKA therapy. Furthermore, subtherapeutic INR levels prior to ECV are associated with the combined endpoint of cardiovascular death, ischemic stroke and the need of blood transfusion.
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands. Electronic address: omer.erkuner@mumc.nl.
authors.forename: Ömer
authors.initials: Ö
authors.lastname: Erküner
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Roy
authors.initials: R
authors.lastname: Claessen
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Ron
authors.initials: R
authors.lastname: Pisters
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Germaine
authors.initials: G
authors.lastname: Schulmer
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Roos
authors.initials: R
authors.lastname: Ramaekers
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Laura
authors.initials: L
authors.lastname: Sonneveld
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Elton
authors.initials: E
authors.lastname: Dudink
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Theo
authors.initials: T
authors.lastname: Lankveld
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Ione
authors.initials: I
authors.lastname: Limantoro
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Bob
authors.initials: B
authors.lastname: Weijs
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Laurent
authors.initials: L
authors.lastname: Pison
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Blaauw
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Cees B
authors.initials: CB
authors.lastname: de Vos
authors.affiliation: Department of Cardiology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Harry Jgm
authors.initials: HJ
authors.lastname: Crijns
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D002561:Cerebrovascular Disorders / Q000097:blood* / Q000453:epidemiology / Q000628:therapy*; D015331:Cohort Studies; D004554:Electric Countershock / Q000379:methods / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000097:blood* / Q000453:epidemiology / Q000628:therapy*; D006801:Humans; D019934:International Normalized Ratio / Q000639:trends; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011446:Prospective Studies; D012042:Registries; D013997:Time Factors; D014812:Vitamin K / Q000037:antagonists & inhibitors
chemical_list: D000925:Anticoagulants; D014812:Vitamin K
keywords: Anticoagulation management; Atrial fibrillation; Cardioversion; Vitamin K antagonist