title: Comparison of left atrial area marked ablated in electroanatomical maps with scar in MRI.
abstract: BACKGROUND
  Three-dimensional electroanatomic mapping (EAM) is routinely used to mark ablated areas during radiofrequency ablation. We hypothesized that, in atrial fibrillation (AF) ablation, EAM overestimates scar formation in the left atrium (LA) when compared to the scar seen on late-gadolinium enhancement magnetic resonance imaging (LGE-MRI).
  
  
  RESULTS
  Of the 235 patients who underwent initial ablation for AF at our institution between August 2011 and December 2012, we retrospectively identified 70 patients who had preprocedural magnetic resonance angiography merged with LA anatomy in EAM software and had a 3-month postablation LGE-MRI for assessment of scar. Ablated area was marked intraprocedurally using EAM software and quantified retrospectively. Scarred area was quantified in 3-month postablation LGE-MRI. The mean ablated area in EAM was 30.5 ± 7.5% of the LA endocardial surface and the mean scarred area in LGE-MRI was 13.9 ± 5.9% (P < 0.001). This significant difference in the ablated area marked in the EAM and scar area in the LGE-MRI was present for each of the 3 independent operators. Complete pulmonary vein (PV) encirclement representing electrical isolation was observed in 87.8% of the PVs in EAM as compared to only 37.4% in LGE-MRI (P < 0.001).
  
  
  CONCLUSIONS
  In AF ablation, EAM significantly overestimates the resultant scar as assessed with a follow-up LGE-MRI.
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Bhrigu R
authors.initials: BR
authors.lastname: Parmar
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Tyler R
authors.initials: TR
authors.lastname: Jarrett
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Nathan S
authors.initials: NS
authors.lastname: Burgon
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Eugene G
authors.initials: EG
authors.lastname: Kholmovski
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Nazem W
authors.initials: NW
authors.lastname: Akoum
authors.affiliation: Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Hu
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Rob S
authors.initials: RS
authors.lastname: Macleod
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Nassir F
authors.initials: NF
authors.lastname: Marrouche
authors.affiliation: Division of Cardiology, CARMA Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Ranjan
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D017115:Catheter Ablation; D002921:Cicatrix / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011667:Pulmonary Veins / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012984:Software; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome; D014589:Utah
keywords: atrial fibrillation; magnetic resonance imaging; radiofrequency ablation