Hands onCatheter ablation of atrial fibrillation originating from extrapulmonary vein areas: Taipei approach
Introduction
The pulmonary veins (PVs) are a dominant source of ectopic activity initiating atrial fibrillation (AF).1, 2 We and others have demonstrated that extra-PV ectopic activity could initiate AF, and elimination of ectopic activity can cure this specific group of patients with AF.3, 4, 5, 6 The Bordeaux group demonstrated that extensive ablation of extra-PV areas after isolation of all four PVs can convert chronic AF to focal or macroreentrant atrial tachycardias, and further elimination of these atrial tachycardias could maintain sinus rhythm in approximately 90% of patients with chronic AF.7 Furthermore, we also showed initiation of AF without any initiating PV ectopy, presumably due to reentry.8 Therefore, we must consider the important role of both ectopy and reentry from extra-PV areas in the initiation and maintenance of AF, not only in patients with paroxysmal AF but also those with chronic AF.
This article describes the current state of mapping and ablation techniques, and the safety and efficacy of catheter ablation for extra-PV AF in patients with paroxysmal and chronic AF.
Section snippets
Provocation of AF initiators
For paroxysmal AF, we attempt to record the spontaneous onset of ectopic activity initiating AF before or after isoproterenol loading. If ectopy does not occur, we recommend short bursts of rapid atrial pacing with brief intermittent pauses between bursts. If AF still does not appear, burst pacing is performed until AF is induced. Once AF is induced and sustained, electrical cardioversion is performed to terminate. Then, we monitor the patient and attempt to record spontaneous AF reinitiation.
Catheter ablation of chronic AF initiated by ectopy from extra-PV areas
The atrial substrate is important in maintaining chronic AF. Therefore, we perform isolation of all four PVs and linear ablation, including the cavotricuspid isthmus, mitral isthmus, and LA roof, in every patient with chronic AF. If AF continues, we convert it to sinus rhythm and then map and ablate any induced focal atrial tachycardia from non-PV areas or macroreentrant atrial tachycardia. Ablation of complex fractionated electrograms are not routinely performed in our laboratory.
Conclusion
Extra-PV ectopic activity and macroreentry can initiate and maintain AF. Considering the relatively high incidence (10%–20%) of extra-PV AF, provocation of AF should be performed during the initial and any repeat procedures.
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