Challenges and Outcomes of Posterior Wall Isolation for Ablation of Atrial Fibrillation.
BACKGROUND
The left atrial posterior wall (PW) often contains sites required for maintenance of atrial fibrillation (AF). Electrical isolation of the PW is an important feature of all open surgeries for AF. This study assessed the ability of current ablation techniques to achieve PW isolation (PWI) and its effect on recurrent AF.


RESULTS
Fifty-seven consecutive patients with persistent or high-burden paroxysmal AF underwent catheter ablation, which was performed using an endocardial-only (30) or a hybrid endocardial-epicardial procedure (27). The catheter ablation lesion set included pulmonary vein antral isolation and a box lesion on the PW (roof and posterior lines). Success in creating the box lesion was assessed as electrical silence of the PW (voltage <0.1 mV) and exit block in the PW with electrical capture. Cox proportional hazards models were used for analysis of AF recurrence. PWI was achieved in 21 patients (36.8%), more often in patients undergoing hybrid ablation than endocardial ablation alone (51.9% versus 23.3%, P=0.05). Twelve patients underwent redo ablation. Five of 12 had a successful procedural PWI, but all had PW reconnection at the redo procedure. Over a median follow-up of 302 days, 56.1% of the patients were free of atrial arrhythmias. No parameter including procedural PWI was a statistically significant predictor of recurrent atrial arrhythmias.


CONCLUSIONS
PWI during catheter ablation for AF is difficult to achieve, especially with endocardial ablation alone. Procedural achievement of PWI in this group of patients was not associated with a reduction in recurrent atrial arrhythmias, but reconnection of the PW was common.
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC.
Prabhat
P
Kumar
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC.
Ayotunde M
AM
Bamimore
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC.
Jennifer D
JD
Schwartz
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC.
Eugene H
EH
Chung
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC.
Anil K
AK
Gehi
Division of Cardiothoracic Surgery, Department of Surgery, The University of North Carolina at Chapel Hill, NC.
Andy C
AC
Kiser
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC.
James P
JP
Hummel
Cardiac Electrophysiology Service, Division of Cardiology, Department of Medicine, The University of North Carolina at Chapel Hill, NC paul_mounsey@med.unc.edu.
J Paul
JP
Mounsey
atrial fibrillation; catheter ablation; hybrid ablation; posterior wall box; posterior wall isolation
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