The Future of Pulmonary Vein Isolation – Single-shot Devices, Remote Navigation or Improving Conventional Radiofrequency Delivery by Contact Monitoring and Lesion Characterisation?

Abstract

59Atrial fibrillation (AF) is the most common sustained arrhythmia in the clinical practice. 1 The prevalence of the arrhythmia is progressively increasing in developed countries and moreover, it is expected to affect up to 12 million people only in the US by 2050.2 Antiarrhythmic drugs continue to represent the first-line of treatment in AF patients, either to restore sinus rhythm or to prevent recurrences.3 However, current antiarrhythmic drugs usually do not achieve complete elimination of the arrhythmia burden and do not have a wide safety profile.4,5 Surgical elimination of certain arrhythmogenic substrates such as AF may represent a therapeutic option. 6 However, nowadays catheter-based ablation is the most common alternative to treat symptomatic patients when antiarrhythmic drugs fail. 3 The cornerstone radiofrequency (RF) catheter-based procedure pioneered by Haïssaguerre and colleagues, of ablating ectopic triggers that arise from the pulmonary veins (PV) in paroxysmal AF, 7 has progressively evolved to new technical developments aiming to simplify pulmonary vein isolation and increase safety. 8 To reach such objectives it is essential to increase catheter stability, achieve predictable lesion formation, reduce procedure and X-ray exposure time, and make simple and automatic either different steps or the whole procedure by using an anatomically-based ablation approach.The so-called single-shot devices for PV isolation, robotic catheter navigation and ablation, contact force-controlled catheter ablation and new realtime imaging of endocardial ablation are the main available technological breakthroughs intending to overcome some of the conventional manual-guided RF delivery shortcomings. The present review is focused on compiling current clinical data, potential advantages and shortcomings of these new ablation strategies for PV isolation. Single-shot DevicesSeveral single-shot devices have been developed in recent years to facilitate PV isolation, based on the encouraging aim of achieving complete isolation of the vein after one single application (single-shot) using circular catheters or balloon-like ablation devices. Among these devices, high-intensity focused ultrasound (HIFU) applied via a balloon catheter (BC) integrates a 9 megahertz (MHz) ultrasound crystal, which generates a ring of ultrasound energy at the base of the balloon. The third generation of HIFU-BC (12 French of outer diameter) is steerable through a pull wire mechanism integrated in the handle of the catheter and is available in balloon sizes (sonication ring diameter) of 24 millimetres (mm) (20 mm), 27 mm (25 mm) and 32 mm (30 mm), respectively (ProRhythm Inc, Ronkonkoma, New York, US). The catheter also has a lumen for insertion of a hexapolar spiral mapping catheter to record PV potentials.Beyond the circumferential lesion design instead of point-by-point ablation, the technology has the potential benefit of not being critically dependent on balloon-to-tissue contact. Initial reports using first and second generation HIFU balloon c...

Anatomical targets and expected outcomes of catheter‐based ablation of atrial fibrillation in 2020

“…In summary, the optimal catheter‐based ablation strategy to eliminate scar areas potentially related to AF maintenance in persistent AF remains unknown and its usefulness is not well established 10 . Isolation of large scar areas may lead to long RF delivery time and potentially increase complications.…”

“…Over the last 20 years, multiple energy sources and a wide variety of ablation strategies have been evaluated to achieve successful pulmonary vein isolation (PVI), while simplifying the procedure and increasing safety outcomes 5–9 . Current technology and ablation approaches achieve high success rates on acute PVI 10 . However, long‐term effective PVI remains a technical and clinical challenge.…”