Box Isolation of Fibrotic Areas (BIFA): A Patient-Tailored Substrate Modification Approach for Ablation of Atrial Fibrillation.
BACKGROUND
Catheter ablation strategies beyond pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF) are less well defined. Increasing clinical data indicate that atrial fibrosis is a critical common left atrial (LA) substrate in AF patients (pts).


OBJECTIVE
We applied a new substrate modification concept according to the individual fibrotic substrate as estimated from electroanatomic voltage mapping (EAVM) in 41 pts undergoing catheter ablation of AF.


RESULTS
First, EAVM during sinus rhythm was done in redo cases of 10 pts with paroxysmal AF despite durable PVI. Confluent low-voltage areas (LVA) were found in all pts and were targeted with circumferential isolation, so-called box isolation of fibrotic areas (BIFA). This strategy led to stable sinus rhythm in 9/10 pts and was transferred prospectively to first procedures of 31 pts with nonparoxysmal AF. In 13 pts (42%), no LVA (<0.5 mV) were identified, and only PVI was performed. In 18 pts (58%), additional BIFA strategies were applied (posterior box in 5, anterior box in 7, posterior plus anterior box in 5, no box in 1 due to diffuse fibrosis). Mean follow-up was 12.5 ± 2.4 months. Single-procedure freedom from AF/atrial tachycardia was achieved in 72.2% of pts and in 83.3% of pts with 1.17 procedures/patient.


CONCLUSIONS
In approximately 40% of pts with nonparoxysmal AF, no substantial LVA were identified, and PVI alone showed high success rate. In pts with paroxysmal AF despite durable PVI and in approximately 60% of pts with nonparoxysmal AF, individually localized LVA were identified and could be targeted successfully with the BIFA strategy.
Hirslanden Hospital, Department of Electrophysiology, Zurich, Switzerland.
Hans
H
Kottkamp
Hirslanden Hospital, Department of Electrophysiology, Zurich, Switzerland.
Jan
J
Berg
Hirslanden Hospital, Department of Electrophysiology, Zurich, Switzerland.
Roderich
R
Bender
Hirslanden Hospital, Department of Electrophysiology, Zurich, Switzerland.
Andreas
A
Rieger
Hirslanden Hospital, Department of Electrophysiology, Zurich, Switzerland.
Doreen
D
Schreiber
D000200:Action Potentials; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D018572:Disease-Free Survival; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005355:Fibrosis; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006329:Heart Conduction System / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006339:Heart Rate; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D012008:Recurrence; D012086:Reoperation; D013997:Time Factors; D016896:Treatment Outcome
atrial fibrillation; catheter ablation; fibrosis; pulmonary vein isolation; substrate modification