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Studies have demonstrated that pulmonary vein (PV) is the major source of ectopic foci initiating paroxysmal atrial fibrillation (PAF). Pulmonary vein isolation (PVI) is recognized to be the cornerstone of radiofrequency catheter ablation for drug-refractory PAF. However, with broadening of indications and pharmacological induction, recent studies suggested that prevalence of non-PV foci initiating PAF varies from 8.9 % to 62% depending on age, sex and underlying heart diseases.
Different from late AF recurrence mainly due to reconnection between PVs and left atrium, non-PV triggers initiating AF accounted for the majority of very late AF recurrence with few evidence of PV reconduction. Available clinical data clearly show that supplemental ablation of non-PV triggers post-PVI, if present, increases arrhythmia-free outcome in patients with PAF. Notably, with drug challenge, patients with non-PV foci exhibiting consistent premature atrial contractions that induced no AF and underwent no further ablation post PVI, had the worse outcome on follow-up, nonetheless, whether they may benefit from further ablation warrants further study.
As yet, the reliability and reproducibility of provocation maneuvers for identifying triggers are poorly characterized, and localization and ablation of non-PV triggers remain challenging to a certain degree.
Based on these issues, whether pharmacological provocation of non-PV foci should be regarded as routine, or better reserved for patients with recurrent AF and isolated PVs, or female, or aged, or patients with underlying heart diseases remains to be determined.