Omnipolar Electrograms in Creation of High-Density Voltage Maps in Patients Undergoing Atrial Fibrillation Catheter Ablation

Introduction: Current strategies for mapping the atrial substrate in patients with a history of atrial fibrillation rely on bipolar peak-to-peak voltage mapping of the atria. This is limited by its reliance on the direction of conduction at the time of recording which may lead to inaccuracies in demarcating low voltage areas and produce false-positive results when assessing for PV isolation at the end of a procedure. We have developed a novel approach, termed omnipolar (OTmax) mapping which provides signals devoid of catheter-orientation dependence but generates the greatest possible voltage. Our hypothesis is that OT mapping may result in a more accurate visualization of the atrial substrate and that this may also help to accurately assess for possible regions of intact conduction across ablation lesions delivered around pulmonary vein antra. Methods: Electroanatomical maps created using the EnSite PrecisionTM cardiac mapping system from data acquired using the AdvisorTM HD Grid Sensor EnabledTM Mapping Catheter were extracted from the system and processed using the Matlab programming environment (R2020b, The MathWorks, Inc) using custom written Matlab functions. OT Vmax, bipolar along ,across, and the maximum peak voltages and surface locations for each mapping point were exported from Velocity and imported into Matlab for analysis and a comparison was made between all of these parameters. Results: OTmax was superior to bipolar mapping in all configurations in the quantification of the mean voltage recorded. OTmax was also found to result in the quantification of signals which would otherwise have been classified as regions of fibrosis. OTmax resulted in higher density physiologically relevant voltage map when compared with all bipolar modalities. OT mapping was superior to bipolar along, across and all bipoles in the detection of electrical points within the ablation zone which revealed regions of conduction not evident on bipolar mapping. Conclusion: OT mapping was superior to bipolar mapping modalities in the visualization of atrial substrate amongst patients undergoing catheter for atrial fibrillation. OT mapping was also shown to be superior to bipolar mapping for the identification of regions of conduction across ablation lesions, which may in part explain recurrences of atrial tachyarrhythmias.