Association of atrial tissue fibrosis identified by delayed enhancement MRI and atrial fibrillation catheter ablation: the DECAAF study.
OBJECTIVE
Left atrial fibrosis is prominent in patients with atrial fibrillation (AF). Extensive atrial tissue fibrosis identified by delayed enhancement magnetic resonance imaging (MRI) has been associated with poor outcomes of AF catheter ablation.


OBJECTIVE
To characterize the feasibility of atrial tissue fibrosis estimation by delayed enhancement MRI and its association with subsequent AF ablation outcome.


METHODS
Multicenter, prospective, observational cohort study of patients diagnosed with paroxysmal and persistent AF (undergoing their first catheter ablation) conducted between August 2010 and August 2011 at 15 centers in the United States, Europe, and Australia. Delayed enhancement MRI images were obtained up to 30 days before ablation.


METHODS
Fibrosis quantification was performed at a core laboratory blinded to the participating center, ablation approach, and procedure outcome. Fibrosis blinded to the treating physicians was categorized as stage 1 (<10% of the atrial wall), 2 (≥10%-<20%), 3 (≥20%-<30%), and 4 (≥30%). Patients were followed up for recurrent arrhythmia per current guidelines using electrocardiography or ambulatory monitor recording and results were analyzed at a core laboratory. Cumulative incidence of recurrence was estimated by stage at days 325 and 475 after a 90-day blanking period (standard time allowed for arrhythmias related to ablation-induced inflammation to subside) and the risk of recurrence was estimated (adjusting for 10 demographic and clinical covariates).


RESULTS
Atrial tissue fibrosis estimation by delayed enhancement MRI was successfully quantified in 272 of 329 enrolled patients (57 patients [17%] were excluded due to poor MRI quality). There were 260 patients who were followed up after the blanking period (mean [SD] age of 59.1 [10.7] years, 31.5% female, 64.6% with paroxysmal AF). For recurrent arrhythmia, the unadjusted overall hazard ratio per 1% increase in left atrial fibrosis was 1.06 (95% CI, 1.03-1.08; P < .001). Estimated unadjusted cumulative incidence of recurrent arrhythmia by day 325 for stage 1 fibrosis was 15.3% (95% CI, 7.6%-29.6%); stage 2, 32.6% (95% CI, 24.3%-42.9%); stage 3, 45.9% (95% CI, 35.5%-57.5%); and stage 4, 51.1% (95% CI, 32.8%-72.2%) and by day 475 was 15.3% (95% CI, 7.6%-29.6%), 35.8% (95% CI, 26.2%-47.6%), 45.9% (95% CI, 35.6%-57.5%), and 69.4% (95% CI, 48.6%-87.7%), respectively. Similar results were obtained after covariate adjustment. The addition of fibrosis to a recurrence prediction model that includes traditional clinical covariates resulted in an improved predictive accuracy with the C statistic increasing from 0.65 to 0.69 (risk difference of 0.05; 95% CI, 0.01-0.09).


CONCLUSIONS
Among patients with AF undergoing catheter ablation, atrial tissue fibrosis estimated by delayed enhancement MRI was independently associated with likelihood of recurrent arrhythmia. The clinical implications of this association warrant further investigation.
Comprehensive Arrhythmia and Research Management Center, University of Utah School of Medicine, Salt Lake City.
Nassir F
NF
Marrouche
Loyola University Medical Center, Maywood, Illinois.
David
D
Wilber
University of Leipzig, Leipzig, Germany.
Gerhard
G
Hindricks
Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France.
Pierre
P
Jais
Comprehensive Arrhythmia and Research Management Center, University of Utah School of Medicine, Salt Lake City.
Nazem
N
Akoum
Hospital of the University of Pennsylvania, Philadelphia.
Francis
F
Marchlinski
Comprehensive Arrhythmia and Research Management Center, University of Utah School of Medicine, Salt Lake City.
Eugene
E
Kholmovski
Comprehensive Arrhythmia and Research Management Center, University of Utah School of Medicine, Salt Lake City.
Nathan
N
Burgon
Comprehensive Arrhythmia and Research Management Center, University of Utah School of Medicine, Salt Lake City.
Nan
N
Hu
University of Barcelona, Barcelona, Spain.
Lluis
L
Mont
BG-Kliniken Bergmannsheil, University of Bochum, Bochum, Germany.
Thomas
T
Deneke
University Hospital Ghent, Ghent, Belgium.
Mattias
M
Duytschaever
Kerckhoff Heart Center, Bad Nauheim, Germany.
Thomas
T
Neumann
Massachusetts General Hospital, Boston.
Moussa
M
Mansour
Klinikum Coburg GmbH, II, Medizinische Klinik, Coburg, Germany.
Christian
C
Mahnkopf
Morsani College of Medicine, University of South Florida, Tampa.
Bengt
B
Herweg
Ohio State University, Columbus.
Emile
E
Daoud
Asklepios Klinik St Georg, Hamburg, Germany.
Erik
E
Wissner
Medical Center Porz am Rhein, Cologne, Germany.
Paul
P
Bansmann
Klinikum Coburg GmbH, II, Medizinische Klinik, Coburg, Germany.
Johannes
J
Brachmann
D000368:Aged; D001281:Atrial Fibrillation / Q000473:pathology* / Q000628:therapy*; D017115:Catheter Ablation; D005260:Female; D005355:Fibrosis; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D012306:Risk; D016896:Treatment Outcome