Trigger vs Substrate Ablation for the Treatment of Atrial Fibrillation

Abstract

Radiofrequency ablation of atrial fibrillation (AF) has emerged as a very effective technique for the treatment of this vexing arrhythmia. When AF ablation was first described by Haissaguerre et al., nearly 10 years ago, the technique focused on the elimination of focal triggers for AF emanating largely from the pulmonary veins (PVs) [1]. In patients with predominantly paroxysmal AF and little structural heart disease, this paradigm remained successful, with evidence confirming that elimination of all possible triggers via pulmonary vein isolation (PVI) would successfully prevent AF recurrence. However, the high success rates of PVI procedures were not replicated in populations with more persistent and permanent AF. In these patients, there is greater interest in identifying the critical elements of the atrial “substrate” required for maintaining AF. By targeting this “substrate,” it is hoped that AF ablation will result in better cure rates in a wider spectrum of AF patients. While markers of AF substrate have been proposed as potential targets of ablation, the efficacy of using such targets is not well known. Furthermore, whether such targets should be eliminated alone, or in conjunction with known triggers is also not well understood.