Mapping and Outcome Implications of Left Atrial Low Voltage Regions as Determined by a Novel 122-electrode Spherical Mapping and Ablation Catheter

Aims A novel 122-electrode spherical mapping/pulsed field ablation (PFA) device is known to effectively ablate atrial fibrillation (AF). The aim of this study is threshold optimization of LVA for the unique geometry of the Globe electrodes and the prognostic association, to evaluate if the extent of low voltage areas could predict recurrence. Methods and Results The PULSAR study was an IDE trial of 183 patients undergoing first-time paroxysmal AF ablation with one-year outcomes of any atrial arrhythmia. During this study, a subset of patients (n=82) had detailed pre-ablation voltage maps performed with the catheter. Pulmonary vein isolation (PVI) was then performed with PFA. Patients were followed with weekly transtelephonic monitoring, ECG, and Holters at 3, 6, and 12 months. Recurrence was defined as any atrial arrhythmia (AA) > 30 seconds. Receiver operator curve (ROC) analysis revealed that a low voltage threshold of 1.0 mV had the highest value (0.735). The percentage LVA surface area resulting from a threshold of 1.0 mV that predicted AA recurrence was 11.6%. Univariate and multivariate analysis revealed the percentage LVA was the strongest predictor of AA recurrence. The 12-month freedom from AA was 84.6% and 52.9% for subjects under and over the low voltage area threshold respectively. Conclusions A voltage threshold of 1.0 mV is proposed as a threshold for defining LVA using the spherical catheter, but a range of approximately 0.5-1.5 mV yielded similar performance. Increased low voltage area in the pre-ablation atrial map was associated with a higher risk of AA recurrence.