Introduction
Catheter ablation (CA) is a pivotal component of the rhythm control strategy in patients with symptomatic atrial fibrillation (AF).1,2 Pulmonary vein isolation (PVI) is well established as the cornerstone procedural target in case of a first AF ablation, due to the prominent role played by pulmonary veins in arrhythmia initiation in paroxysmal AF.1,2
However, procedural outcomes are still suboptimal in patients with persistent AF, and in these subjects additional anatomical structures and/or electrophysiological triggers are commonly ablated on top of PVI, in an attempt to improve ablation effectiveness.2-5
In recent years, we have witnessed a renewed interest in atrial anatomy and in the role of epicardial structures, such as Bachmann’s bundle (BB) and the ligament of Marshall (LOM), as critical determinants of AF.6,7 At the same time, percutaneous epicardial ablation has gained popularity as an important component of the therapeutic armamentarium for ventricular tachycardia.8
Driven by the desire to address arrhythmogenic epicardial structures while avoiding complications related to a thoracotomic approach, minimally invasive epicardial ablation for AF has now entered the clinical arena, and some preliminary experiences supported its feasibility and allowed a greater understanding of the transmurality of the AF substrate, with encouraging clinical results.9-11
Based on these preliminary observations, we developed a combined endo-/epicardial stepwise protocol for AF CA in patients with persistent or longstanding persistent AF and one or more prior endocardial procedures, the Mediterranea approach. In the present study, we describe our protocol in detail, focusing on technical aspects of the epicardial approach to relevant atrial structures, providing insights into the sites of AF termination, and reporting clinical outcomes.