Automated analysis of pulmonary vein electrograms during pulsed field ablation

Pulsed Field Ablation (PFA) is emerging as a reliable energy source for pulmonary vein isolation (PVI) in the treatment of atrial fibrillation (AF). Accurate dose titration is essential to prevent reversible electroporation and to optimize tissue response.

To determine the utility of automated analysis of unipolar electrograms (EGMs) pre- and post-PFA delivery in assessing tissue response.

Unfiltered unipolar EGMs were acquired using a proprietary pentaspline basket catheter (Boston Scientific Inc., USA) before and after PFA energy delivery. Data from five patients with paroxysmal AF undergoing PVI were retrospectively analyzed. Each PV was treated using conventional PFA delivery, with pairs in basket configuration and pairs in flower configuration. The unipolar EGMs were processed through an algorithm (PFAnalyzer) developed by CathVision, Denmark. The PFAnalyser algorithm decomposed single-beat unipolar EGMs to isolate the local potential (LP), removing far-field and near-field potentials, as well as the injury current induced by PFA delivery. A peak-to-peak threshold of 0.1 mV was used to identify absence of LPs.

A total of 216 unipolar EGMs from five procedures were analyzed: 108 prior to each double-pulse PFA application and 108 after the first PFA pulse in each application. Prior to each double-pulse PFA application, all 108 recorded EGMs exhibited LPs with an average amplitude of 0.183 mV. Following the first delivery of each double-pulse PFA application, residual LPs were detected in 46.3% (50 of 108) of recordings, with an average amplitude of 0.121 mV. Figure 1 shows the amplitudes of EGMs before and after the first PFA delivery of each double-pulse application, as well as the amplitudes of 21 EGMs recorded before the initial and after the final PFA application for each vein. After the final PFA application, the average amplitude decreased to 0.06 mV, below the 0.1mV threshold used to confirm the absence of residual EGMs. Figure 2 shows the time-evolution of EGMs during a double-pulse PFA application, along with the detected LPs and their amplitudes.

Automated EGMs analysis effectively identifies PV LPs and residual EGMs in unipolar recordings. Local PV potentials indicate effective tissue contact, while residual signals after the first PFA delivery suggest incomplete isolation. The complete reduction in EGM amplitude following the final PFA application for each vein confirms that the detected signal after first PFA delivery was indeed a residual LP.