Omnipolar Versus Bipolar Electrode Mapping in Patients With Atrial Fibrillation Undergoing Catheter Ablation

Peak-to-peak bipolar voltage varies with electrode orientation, fractionation, and collision events. Novel, omnipolar mapping is less dependent on electrode orientation but has limited data in humans.

This study sought to compare bipolar peak-to-peak voltage with omnipolar maximum voltage (V_max) during sinus rhythm in the left atrium of patients with persistent (PerAF) or paroxysmal atrial fibrillation (PAF).

Baseline voltage maps were generated with bipolar and omnipolar mapping in 20 patients undergoing de novo catheter ablation for PerAF or PAF and 9 patients with known scar from prior cardiac surgery, to validate voltage-based scar approximations. Low voltage was defined as <0.5 mV and scar <0.1 mV. Mean voltage was compared with unpaired t testing. Percent low voltage and scar were compared with chi-square testing. A point-to-point comparison was performed with Bland-Altman analysis.

The mean age was 62.2 ± 9.9 years, 34% were women, and 41% had heart failure. Omnipolar mapping identified significantly higher mean voltage than bipolar mapping and classified less points as low voltage (PerAF: 32.90% vs 43.40%; PAF: 19.20% vs 25.60%) and scar (PerAF: 7.72% vs 12.10%; PAF: 4.03% vs 6.07%) (all P < 0.0001). Omnipolar V_max displayed significant disagreement with bipolar by Bland-Altman analysis. Scar and low-voltage approximations were validated in atria with known scar, in which bipolar mapping overestimated the extent of low voltage (P < 0.0001) and scar (P < 0.0001).

Omnipolar mapping identifies higher voltage and has greater specificity for the detection of low voltage and scar than conventional bipolar mapping in patients with PerAF or PAF.