Specialized conduction tissue derived from the heart tube with intrinsic pacemaker activity has been demonstrated in these myocardial sleeves. First, the posterior wall and its myocardial extensions into the PVs share similar embryologic origins. The posterior LA may play a critical role in the initiation and maintenance of AF for multiple reasons. The role of the posterior left atrium in atrial fibrillation Most studies show an incremental benefit of posterior wall ablation in addition to PVI in patients with persistent AF, although patient selection for this strategy remains an area of active investigation. In this review, we will examine the mechanistic role of the posterior LA, discuss the technical challenges of ablating in the posterior wall and the evolution of strategies to achieve isolation with catheter approaches, and review the relevant literature available to date. 9 These observations have motivated the development of catheter-based techniques to achieve complete posterior wall isolation in an effort to improve ablation outcomes.Ĭurrently, the role for posterior wall isolation during catheter ablation of AF is controversial. 8 When isolated en bloc in patients with persistent AF, it has been found that the posterior LA can still sustain AF in some patients, while the remaining atria cannot. 6, 7 During encircling of the posterior wall, the shortest atrial cycle lengths are often found in this region. The original Cox maze procedure and its modifications, which generally include complete exclusion of the posterior LA, have demonstrated efficacy even in those with longstanding persistent AF. Observations from surgical isolation of the posterior LA in humans have implicated the region between the PVs as a potential major contributor to persistent AF. 2, 4 However, PVI alone, which exudes a variable amount of posterior wall tissue, is often an insufficient treatment method for patients with persistent AF. 3 PV isolation (PVI) has emerged as a highly effective therapy for patients with paroxysmal AF. Ectopic beats originating from the PVs initiate the majority of paroxysmal AF, 2 and frequency gradients emanating from the posterior LA to the rest of the atria are often seen during sustained fibrillation. In paroxysmal AF, the posterior wall has been demonstrated to have a role in both the initiation and maintenance of AF episodes. Notably, the left atrium (LA) appears to play a dominant role in the establishment and maintenance of AF in most patients with the condition and, in particular, the posterior wall and pulmonary veins (PVs) frequently harbor sources of fibrillation. 1 Catheter ablation improves quality of life in patients with AF and has emerged as either a first-line therapy option or as an alternative therapy in those patients with symptomatic AF refractory to medical therapy. Furthermore, in recent years, the prevalence of AF has risen and is projected to increase threefold by 2050 as the population ages. Paul Mounsey, MD, 160 Dental Circle CB7075, Chapel Hill, NC 27599, USA.Ītrial fibrillation (AF) is the most common sustained arrhythmia in humans and is associated with significant morbidity and mortality. Final version accepted September 12, 2017.Īddress correspondence to: J. Hummel report no conflicts of interest for the published content. Mounsey reports a role as a consultant and receiving speaker’s honoraria from Boston Scientific, Medtronic, and Abbott Laboratories, and receiving speaker’s honoraria from Janssen Pharmaceuticals. Atrial fibrillation, catheter ablation, posterior wall isolation.ĭr. In this review, we will examine the mechanistic role of the posterior left atrium, discuss the technical challenges of ablating in the posterior wall and the evolution of strategies to achieve isolation with catheter approaches, and review the relevant literature to date. Currently, the role of posterior wall isolation during catheter ablation of AF is controversial. The left atrium appears to play a dominant role in the condition of most patients with AF and, in particular, the posterior wall and pulmonary veins frequently harbor sources of fibrillation. Catheter ablation is widely utilized for the management of atrial fibrillation (AF), particularly in patients who are refractory to medical therapy. HUMMEL, MD 2ġ Department of Internal Medicine, Division of Cardiology, University of North Carolina at Chapel Hill, NC, USAĢ Department of Internal Medicine, Division of Cardiac Electrophysiology, University of North Carolina at Chapel Hill, NC, USAĪBSTRACT. Posterior Wall Isolation in Atrial Fibrillation Ablation
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