Ablation of Advanced Subtypes of Atrial Fibrillation: Highlighting the Art of When and When Not to Perform Additional Ablation

Abstract

The purpose of this review is to determine the role of pulmonary vein (PV) triggers in different types of atrial fibrillation (AF) as well as to determine based on prospective randomized data which other approaches may increase the success rate of radiofrequency ablation of persistent AF. Special attention must be paid to detect, diagnose, and optimize management of reversible or treatable causes of persistent AF such as obesity, obstructive sleep apnea, hypertension, hypo- or hyperthyroidism, inflammatory and infectious diseases, and stress. Though the role of PVs is more pronounced in paroxysmal AF than in persistent AF, performing an adequate PV isolation is still a key part in treating persistent AF. There are now numerous techniques to obtain long-lasting pulmonary vein isolation and avoid esophageal damage. Patients with persistent AF will frequently require a more aggressive mapping and ablative approach. Ablation of sites associated with non-PV triggers such as the entire posterior wall, the roof, the anterior part of the left atrial (LA) septum, the left atrial appendage (LAA), the coronary sinus, and the superior vena cava has been shown to improve the freedom from AF at follow-up when combined with PV isolation. We do not encourage the use of empiric lines or complex fractionated atrial electrograms. Several studies have shown the role of empirical LAA electrical isolation in persistent AF. When focal ectopic atrial activity is observed after PV isolation, its activation sequence is compared to that of sinus rhythm, allowing quick identification of its origin. For significant non-PV triggers (repetitive isolated beats, focal atrial tachycardias or beats triggering AF/atrial flutter), a more detailed activation mapping is performed in the area of origin. They are subsequently targeted with focal ablation, except for triggers originating from the superior vena cava (SVC), LAA, or coronary sinus, for which complete isolation of these structures is the ablation strategy of choice. We truly believe the LAA and the posterior LA wall deserve special consideration when managing patients with persistent AF.