title: Low incidence of left atrial delayed enhancement with MRI in patients with AF: a single-centre experience.
abstract: Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. One potential target for ablation is left atrial (LA) scar (LAS) regions that may be the substrate for re-entry within the atria, thereby sustaining AF. Identification of LAS through LA delayed gadolinium enhancement (LADE) with MRI has been proposed.
  
  
  
  We sought to evaluate LADE in patients referred for catheter ablation of AF.
  
  
  
  Prospective analysis was conducted of consecutive patients who underwent pulmonary vein antrum isolation (PVAI) ablation for AF at a single institution. Patients underwent LADE with MRI to determine LAS regions before ablation. MRI data were analysed independently in accordance with prespecified institutional protocol by two staff cardiac radiologists to whom patient outcomes were masked, and reports of LADE were documented. Where no initial consensus occurred regarding delayed enhancement (DE), a third staff cardiac radiologist independently reviewed the case and had the deciding vote.
  
  
  
  Of the 149 consecutive patients (mean (SD) age, 59 (9) years), AF was persistent in 64 (43%) and paroxysmal in 85 (57%); 45 (30%) had prior ablation. Only five patients (3%) had identifiable DE in LA walls (persistent AF, n=1; paroxysmal AF, n=4). LADE was present in two (4%) of the 45 patients with previous left PVAI. The presence of LADE was not associated with a higher recurrence rate of AF.
  
  
  
  In contrast to previous studies, the finding of DE within LA walls was uncommon and, when present, did not correlate with AF type or risk of AF recurrence. It therefore is of unclear clinical significance.
authors.affiliation: Division of Cardiovascular Diseases , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Bois
authors.affiliation: Department of Radiology , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: James
authors.initials: J
authors.lastname: Glockner
authors.affiliation: Department of Radiology , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Young
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA; Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Foley
authors.affiliation: Division of Cardiovascular Diseases , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: Seth
authors.initials: S
authors.lastname: Sheldon
authors.affiliation: Division of Cardiovascular Diseases , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: Darrell B
authors.initials: DB
authors.lastname: Newman
authors.affiliation: Division of Cardiovascular Diseases , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: Grace
authors.initials: G
authors.lastname: Lin
authors.affiliation: Division of Cardiovascular Diseases , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.affiliation: Division of Cardiovascular Diseases , Mayo Clinic , Rochester, Minnesota , USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Brady