Pulmonary vein anatomy assessment prior to atrial fibrillation ablation using balloon-based technologies: can it really be abandoned?

This editorial refers to ‘Impact of pulmonary vein anatomy assessed by cardiac magnetic resonance imaging on endoscopic pulmonary vein isolation in consecutive patients’ by A. Metzner et al., on page 474 Catheter ablation has become an established treatment modality for patients with symptomatic, drug-refractory atrial fibrillation. Moreover, current guidelines recommend that catheter ablation may be considered first-line therapy in selected patients with paroxysmal atrial fibrillation and minimal or no heart disease. 1 Consequently, the number of patients deemed suitable for interventional treatment of atrial fibrillation is steadily increasing. It has been accepted that pulmonary vein (PV) isolation forms the cornerstone of any atrial fibrillation ablation strategy. Traditionally, radiofrequency energy is applied in a point-by-point fashion using a standard mapping and ablation catheter to accomplish the lesion set. This approach, however, is technically demanding due to complex anatomy of the left atrium and PVs, respectively, necessitating a high level of expertise. Pre- and peri-procedural imaging of the left atrium and PVs [e.g. by computed tomography, magnetic resonance imaging (MRI), transoesophageal echocardiography, rotational angiography] helps to understand the individual cardiac anatomy thus facilitating catheter navigation and lesion placement particularly after integration into a 3D electroanatomic mapping system. Within the last several years, new technologies specifically designed for PV isolation have been introduced in order to simplify the ablation procedure. Balloon-based catheter designs using cryo-energy or high-intensity-focused ultrasound may allow for continuous lesion placement with only a few energy applications (‘single-shot’ devices). These approaches, however, are limited by fixed balloon sizes which do not sufficiently account for the variable PV anatomy and which renders wide circumferential lesion placement at the antral level of the PVs difficult.