Ab-452675-3 characteristics of residual signals after pulsed field ablation of the pulmonary veins

Pulsed field ablation (PFA) is a new energy source for isolation of the pulmonary veins in the treatment of paroxysmal atrial fibrillation (PAF). Dose titration is challenging but important to avoid reversible electroporation. Analysis of high resolution unipolar electrograms after PFA might be of value to analyze the tissue response to PFA deliveries. Unipolar and bipolar electrograms were recorded from a proprietary pentaspline basket catheter (Boston Scientific Inc., USA) before and after PFA energy delivery using a novel electrophysiology recording system (ECGenius System, CathVision, Denmark) with resolution at a 0.05 mV level and a sampling rate of 2 KHz. Data was recorded from 12 consecutive patients diagnosed with PAF and scheduled for pulmonary vein isolation. The treatment protocol consisted of conventional PFA delivery in two baskets and two flower positions for each vein. Both unipolar and bipolar signals were analyzed manually. Overall, 790 EGMs from 12 patients were analyzed. In 131 out of 160 EGMs (82%) recorded after first PFA delivery, we observed a residual sharp downward deflection in the unipolar signal that matched the timing of the corresponding bipolar signal (Fig. 1). Median amplitude of the deflection was 0.18 mV (IQR = 0.09 - 0.32 mV). The sharp deflections were eliminated with further PFA delivery in 29.7% of cases (suggesting true local activation) but persisted in 71.3%. High resolution electrogram recording allows identification of residual sharp deflections in the unipolar electrogram after PFA delivery. The coincident timing with the bipolar EGM together with elimination by further PFA suggests that this EGM signature reflects true local activity. It remains to be seen whether persisting deflections are a measure for non-isolation or reversible electroporation.