Prospective Evaluation of Biophysical Parameters as Long-term Predictors of Pulmonary Vein Isolation

Overview

Current, worldwide assessments of the prevalence of AF estimate that 33 million people are affected by this cardiac arrhythmia. As the most common sustained atrial arrhythmia, AF has a well-established association with systemic embolic events, stroke, heart failure, and increased mortality. Current treatment guidelines and consensus statements for patients with AF suggest that most patients should be first managed with a pharmaceutical drug therapy; however, when a patient becomes drug refractory (intolerant or non-responsive), catheter ablation by PV isolation (PVI) is recommended. The aim of PVI is abolishment of all conducted electrical activity beyond the isolating lesions. The recent NICE guidelines have established that today RF point-by-point ablation is the most cost-effective treatment approach over a lifetime after failure of 1 or more anti-arrhythmic drugs5, but until now a new technology, HELIOSTAR, RF Balloon, has not been included in this cost-effectiveness analysis

The multi-electrode RF Balloon catheter (HELIOSTAR, Biosense Webster) is a compliant Balloon with 10 circularly orientated electrodes bonded to its surface. It has been designed to be used in conjunction with the Carto3 system (Biosense Webster, CA). It is able to deliver RF energy directly forming a continuous circular ablation lesion around the PV ostia. With HELIOSTAR, each individual electrode can sense temperature and can be controlled separately. The electrodes can be used for visualization, stimulation, recording and ablation. The compliance of the Balloon allows conformation to the anatomy of the PVs and therefore maximizing tissue contact. The advantages of the RF Balloon include the ease of use to the operator that is associated with Balloon delivery systems, possibility of single shot PVI with tailored RF energy delivery, potentially shorter procedure times and avoidance of collateral damage to non-PVI structures, due to the capacity to individually select and deselect electrodes during ablation.6,7 To date, retrospective analyzes conducted in the RADIANCE and SHINE studies have shown the pre-ablation indicators of optimal electrode positioning and post-RF indicators associated with better outcomes; specifically, baseline impedance range 90-110 Ohms, impedance variability across ten electrodes ≤20 Ohms, baseline electrode temperature ≤31°C, baseline temperature variability ≤3°C and the post-RF indicators (impedance drop ≥12 Ohm and temperature rise ≥6°C) seem to independently predict a durable PVI. To the best of our knowledge, no studies have investigated prospectively the performance of impedance drop and temperature rise of HELIOSTAR ablation in terms of feasibility, acute PVI and post-procedural outcomes.