Unipolar voltage mapping to predict lesion durability during pulsed field ablation

Unipolar electrograms (u-EGM) may help assess lesion durability with pulsed field ablation (PFA).

We aimed to validate the voltages associated with u-EGM changes after PFA and assess the predictive value for lesion durability.

Patients undergoing PFA using a pentaspline catheter were enrolled. Unipolar and bipolar voltage maps were created (baseline and every 5 minutes post-PFA), after a single or double PFA application. In group 1 (N = 10), areas with loss of S wave on u-EGM ("core") were correlated with unipolar voltage amplitude using receiver operator characteristic analysis. In group 2 (N = 41), lesion durability was correlated with unipolar voltage. In group 3 (N = 69), an esophageal catheter recorded EGMs as surrogates of epicardial EGMs. In group 4 (N = 21), u-EGMs of initial ablations were evaluated in patients undergoing redo procedures.

Unipolar voltage ≤0.4 mV optimally predicted S-wave loss. Core lesions defined by this threshold remained temporally stable, whereas halo regions (>1.08 mV unipolar, >0.5 mV bipolar) demonstrated recovery. Double applications produced larger and more durable lesions than single applications (2.27 cm² vs 0.49 cm², P = .0075). Esophageal S-wave re-emergence occurred in single but not double applications, suggesting reversible electroporation. In redo procedures, we found that a unipolar voltage ≥0.4 mV independently predicted areas of conduction recovery.

A unipolar voltage ≤0.4 mV and loss of the terminal S wave on the u-EGM identify regions of durable ablation. Unipolar mapping may provide critical insights into durability and guide more effective PFA.