Magnetic resonance imaging-confirmed ablative debulking of the left atrial posterior wall and septum for treatment of persistent atrial fibrillation: rationale and initial experience.
BACKGROUND
Though pulmonary vein (PV) isolation has been widely adopted for treatment of atrial fibrillation (AF), recurrence rates remain unacceptably high with persistent and longstanding AF. As evidence emerges for non-PV substrate changes in the pathogenesis of AF, more extensive ablation strategies need further study.


METHODS
We modified our PV antrum isolation procedure to include abatement of posterior and septal wall potentials. We also employed recently described image-processing techniques using delayed-enhancement (DE) MRI to characterize tissue injury patterns 3 months after ablation, to assess whether each PV was encircled with scar, and to assess the impact of these parameters on procedural success.


RESULTS
118 consecutive patients underwent debulking procedure and completed follow-up, of which 86 underwent DE-MRI. The total left atrial (LA) radiofrequency delivery correlated with percent LA scarring by DE-MRI (r = 0.6, P < 0.001). Based on DE patterns, complete encirclement was seen in only 131 of 335 PVs (39.1%). As expected, Cox regression analysis showed a significant relationship between the number of veins encircled by delayed enhancement and clinical success (hazard ratio of 0.62, P = 0.015). Also, progressive quartile increases in postablation posterior and septal wall scarring reduced recurrences rates with a HR of 0.65, P = 0.022 and 0.66, P = 0.026, respectively.


CONCLUSIONS
Pathologic remodeling in the septal and posterior walls of the LA helps form the pathogenic substrate for AF, and these early results suggest that more aggressive treatment of these regions appears to correlate with improved ablation outcomes. Noninvasive imaging to characterize tissue changes after ablation may prove essential to stratifying recurrence risk.
University of Utah Atrial Fibrillation Program, Department of Internal Medicine, University of Utah Hospitals & Clinics, Salt Lake City, Utah, USA.
Nathan M
NM
Segerson
Marcos
M
Daccarett
Troy J
TJ
Badger
Akram
A
Shabaan
Nazem
N
Akoum
Eric N
EN
Fish
Swati
S
Rao
Nathan S
NS
Burgon
Yaw
Y
Adjei-Poku
Eugene
E
Kholmovski
Sathya
S
Vijayakumar
Edward V R
EV
DiBella
Rob S
RS
MacLeod
Nassir F
NF
Marrouche
D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000601:surgery*; D006329:Heart Conduction System / Q000473:pathology / Q000601:surgery*; D006346:Heart Septum / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010865:Pilot Projects; D016896:Treatment Outcome