title: Evaluation and reduction of asymptomatic cerebral embolism in ablation of atrial fibrillation, but high prevalence of chronic silent infarction: results of the evaluation of reduction of asymptomatic cerebral embolism trial.
abstract: BACKGROUND
  This prospective, multicenter study sought to evaluate the incidence of asymptomatic cerebral emboli (ACE) during ablation of atrial fibrillation (AF) using a multielectrode radiofrequency (MER) system when specific procedural changes were applied.
  
  
  RESULTS
  Sixty subjects (age 60±10 years; 87% paroxysmal; CHADS2 score, 0.6±0.7) undergoing AF ablation with a circular MER catheter were studied. Three procedural changes were specified: (1) ablation was performed under therapeutic vitamin K antagonist and heparin to maintain activated clotting time>350 seconds; (2) submerged loading of the catheter into the introducer before sheath insertion to minimize air ingress; and (3) either the distal or proximal electrode of the circular MER catheter was deactivated to prevent inadvertent bipolar radiofrequency interaction. MRI was performed <7 days preablation and 2 days postablation. Subjects with new cerebral findings after ablation underwent repeat MRI after 1 month. An acute ACE lesion was defined by a new hyperintensity on diffusion-weighted and fluid-attenuated inversion recovery cerebral MRI sequences. Neurological function was evaluated at baseline, postablation, and 1 month. All target pulmonary veins were isolated. In 60% (36/60) of patients, pre-existing cerebral lesions were seen on the preprocedure MRI (8 lesions per subject; interquartile range, 3-22). New postprocedural ACE occurred in only 1/60 patients (incidence, 1.7%; 95% confidence interval, 0.04-8.9), which was no longer visible on MRI after 1 month.
  
  
  CONCLUSIONS
  Applying procedural changes to MER ablation significantly reduces the ACE incidence to 1.7%, which is on the low end of reported ACE rates of any technology.
  
  
  BACKGROUND
  ClinicalTrials.gov; Identifier: NCT01520532.
authors: Southlake Regional Health Center, Newmarket, Ontario, Canada.
authors: Atul
authors: A
authors: Verma
authors: Philippe
authors: P
authors: Debruyne
authors: Stefano
authors: S
authors: Nardi
authors: Thomas
authors: T
authors: Deneke
authors: Yves
authors: Y
authors: DeGreef
authors: Stefan
authors: S
authors: Spitzer
authors: Jörn O
authors: JO
authors: Balzer
authors: Lucas
authors: L
authors: Boersma
mesh_terms: D001281:Atrial Fibrillation / Q000150:complications* / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects*; D002544:Cerebral Infarction / Q000453:epidemiology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D015994:Incidence; D020766:Intracranial Embolism / Q000453:epidemiology / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies
keywords: atrial fibrillation; catheter ablation; cerebral infarction; clinical trial; embolism