title: Poor scar formation after ablation is associated with atrial fibrillation recurrence.
abstract: OBJECTIVE
  Patients routinely undergo ablation for atrial fibrillation (AF) but the recurrence rate remains high. We explored in this study whether poor scar formation as seen on late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) correlates with AF recurrence following ablation.
  
  
  METHODS
  We retrospectively identified 94 consecutive patients who underwent their initial ablation for AF at our institution and had pre-procedural magnetic resonance angiography (MRA) merged with left atrial (LA) anatomy in an electroanatomic mapping (EAM) system, ablated areas marked intraprocedurally in EAM, 3-month post-ablation LGE-MRI for assessment of scar, and minimum of 3-months of clinical follow-up. Ablated area was quantified retrospectively in EAM and scarred area was quantified in the 3-month post-ablation LGE-MRI.
  
  
  RESULTS
  With the mean follow-up of 336 days, 26 out of 94 patients had AF recurrence. Age, hypertension, and heart failure were not associated with AF recurrence, but LA size and difference between EAM ablated area and LGE-MRI scar area was associated with higher AF recurrence. For each percent higher difference between EAM ablated area and LGE-MRI scar area, there was a 7-9% higher AF recurrence (p values 0.001-0.003) depending on the multivariate analysis.
  
  
  CONCLUSIONS
  In AF ablation, poor scar formation as seen on LGE-MRI was associated with AF recurrence. Improved mapping and ablation techniques are necessary to achieve the desired LA scar and reduce AF recurrence.
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Bhrigu R
authors.initials: BR
authors.lastname: Parmar
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Tyler R
authors.initials: TR
authors.lastname: Jarrett
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Eugene G
authors.initials: EG
authors.lastname: Kholmovski
authors.affiliation: Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Hu
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Dennis
authors.initials: D
authors.lastname: Parker
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Rob S
authors.initials: RS
authors.lastname: MacLeod
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Nassir F
authors.initials: NF
authors.lastname: Marrouche
authors.affiliation: CARMA Center, Division of Cardiology, University of Utah, Salt Lake City, UT, 84132, USA. ravi.ranjan@hsc.utah.edu.
authors.forename: Ravi
authors.initials: R
authors.lastname: Ranjan
mesh_terms: D017677:Age Distribution; D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control*; D017115:Catheter Ablation; D002921:Cicatrix / Q000453:epidemiology* / Q000473:pathology*; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D011379:Prognosis; D011667:Pulmonary Veins / Q000601:surgery*; D012008:Recurrence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014589:Utah / Q000453:epidemiology
keywords: Ablation; Atrial fibrillation; MRI; Poor scar formation; Recurrence