MRI Assessment of Ablation-Induced Scarring in Atrial Fibrillation: Analysis from the DECAAF Study.
BACKGROUND
There is limited knowledge on the extent and location of scarring that results from catheter ablation and its role in suppressing atrial fibrillation (AF). We examined the effect of atrial fibrosis and ablation-induced scarring on catheter ablation outcomes in AF.


METHODS
We conducted a prospective multicenter study that enrolled 329 AF patients presenting for catheter ablation. Delayed enhancement magnetic resonance imaging (DE-MRI) of the left atrium was obtained preablation. Scarring was evaluated in 177 patients with a DE-MRI scan obtained 90 days postablation. We evaluated residual fibrosis, defined as preablation atrial fibrosis not covered by ablation scar. The primary outcome was freedom from recurrent atrial arrhythmia.


RESULTS
In the analysis cohort of 177 patients, preablation fibrosis was 18.7 ± 8.7% of the atrial wall. Ablation aimed at pulmonary vein (PV) isolation was performed in 163 patients (92.1%). Ablation-induced scar averaged 10.6 ± 4.4% of the atrial wall. Scarring completely encircled all 4 PVs only in 12 patients (7.3%). Residual fibrosis was calculated at 15.8 ± 8.0%. At 325 days follow-up, 35% of patients experienced recurrent arrhythmia. Multivariable Cox proportional hazards models demonstrated that baseline atrial fibrosis (HR and 95% CIs) (1.09 [1.06-1.12], P < 0.001) and residual fibrosis (1.09 [1.05-1.13], P < 0.001) were associated with atrial arrhythmia recurrence, while PV encirclement and overall scar were not.


CONCLUSIONS
Catheter ablation of AF targeting PVs rarely achieves permanent encircling scar in the intended areas. Overall atrial fibrosis present at baseline and residual fibrosis uncovered by ablation scar are associated with recurrent arrhythmia.
Atrial Fibrillation Program, University of Washington, Seattle, Washington, USA.
Nazem
N
Akoum
Loyola University Medical Center, Illinois, USA.
David
D
Wilber
University of Leipzig, Germany.
Gerhard
G
Hindricks
Centre Hospitalier Universitaire de Bordeaux, France.
Pierre
P
Jais
Comprehensive Arrhythmia and Research Management (CARMA) Center, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Josh
J
Cates
Hospital of the University of Pennsylvania, Pennsylvania, USA.
Francis
F
Marchlinski
Comprehensive Arrhythmia and Research Management (CARMA) Center, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Eugene
E
Kholmovski
Comprehensive Arrhythmia and Research Management (CARMA) Center, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Nathan
N
Burgon
Comprehensive Arrhythmia and Research Management (CARMA) Center, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Nan
N
Hu
Hospital Clinic, Universiat de Barcelona, Institut d'investigació Biomèdica August Pi Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.
Lluis
L
Mont
BG-Kliniken Bergmannsheil, University of Bochum, Germany.
Thomas
T
Deneke
University Hospital Ghent, Belgium.
Mattias
M
Duytschaever
Kerckhoff Heart Center, Germany.
Thomas
T
Neumann
Massachusetts General Hospital, Massachusetts, USA.
Moussa
M
Mansour
Klinikum Coburg, II. Medizinische Klinik, Germany.
Christian
C
Mahnkopf
Centre Hospitalier Universitaire de Bordeaux, France.
Mathew
M
Hutchinson
USF Morsani College of Medicine, Florida, USA.
Bengt
B
Herweg
Ohio State University, Ohio, USA.
Emile
E
Daoud
Asklepios Klinik St. Georg, Germany.
Erik
E
Wissner
Klinikum Coburg, II. Medizinische Klinik, Germany.
Johannes
J
Brachmann
Comprehensive Arrhythmia and Research Management (CARMA) Center, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Nassir F
NF
Marrouche
D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D001315:Australia; D017115:Catheter Ablation / Q000009:adverse effects; D002921:Cicatrix / Q000473:pathology*; D005060:Europe; D005260:Female; D005355:Fibrosis; D006325:Heart Atria / Q000473:pathology / Q000601:surgery*; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000503:physiopathology / Q000601:surgery*; D012008:Recurrence; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States
atrial fibrillation; atrial scar; cardiac MRI; catheter ablation; pulmonary vein isolation