The omnipolar voltages as an ablation indicator for pulmonary vein isolation in patients with atrial fibrillation

Abstract

Abstract Background Lesion Index (LSI) without considering myocardial voltage is well-known to guide pulmonary vein isolation (PVI) ablation using the TactiCath™ Ablation Catheter in paroxysmal atrial fibrillation (PAF) patients. However, some patients show gaps after LSI-guided PVI ablation. Meanwhile, the omnipolar voltages detected using EnSite™ Omnipolar Technology (OT) have been reported to improve the underestimation of voltage. Purpose We aimed to clarify their differences by comparing the omnipolar voltages with conventional bipolar voltages and to verify whether it could be an additional indicator of LSI. Methods [Study1] We retrospectively studied 48 PAF patients (32 male, 69±8yrs) who received catheter ablation (CA). The left atrial voltage mapping was performed with Advisor™ HD Grid Mapping Catheter under right atrial pacing. The voltages within a 1cm diameter circle were measured at each site (Roof, Anterior, Posterior, Septal, Lateral; 238 sites) and evaluated the omnipolar and conventional bipolar voltages. [Study2] Twelve patients (8 males, 71±9yrs) with PAF who underwent CA were prospectively studied. The left atrial voltage mapping was performed before PVI ablation. The pre-ablation omnipolar voltages / bipolar voltages and LSI on each ablation site (558 points) of the PVI line were measured and compared in gapped and non-gapped regions. The gapped areas were defined as sites that required additional ablation after the first-round ablation of PVI. Results [Study1] The omnipolar voltages were higher than the bipolar voltages (total 238 sites, 2.84±2.05 vs. 2.67±1.81 mV, P<0.0001) in the entire left atrium. There was no feature in the difference between the omnipolar voltage and the bipolar voltage, according to the site and the voltage height (Figure). [Study2] Five gaps (14 ablation points) were confirmed after the first round of LSI-guided PVI (LSI 4.5±0.4, minimum 3.8 - maximum 5.8) in 4 of 12 patients. The omnipolar voltage in the gapped areas was higher than the non-gapped areas (544 ablation points) (5.64±1.93 vs. 3.73±2.82mV, P=0.0118, cut-off value 3.56mV, the area under the curve 0.74678). Meanwhile, there was no difference between the gapped and non-gapped areas in LSI and the conventional bipolar voltage. Conclusion Although the omnipolar voltage obtained by OT is detected only slightly higher than the bipolar potential, the higher omnipolar voltage could be an indicator of additional ablation to the LSI.