Comparative efficacy and safety of pulse field ablation using monopolar versus bipolar discharge mode in ventricles
Z Zhang, Q Xu, Y A O Yan, L DingAbstract
Backgrounds
Pulsed-field ablation (PFA) is an emerging nonthermal technology in the field of arrhythmia catheter ablation. Currently, little is known about the comparative efficacy of pulsed-field ablation (PFA) using monopolar versus bipolar discharge mode in the ventricles.
Purposes
This study aims to analyze the impact of monopolar versus bipolar PFA on ablation lesion size in the potato and porcine model. In addition, we fitted the formula of pulsed field energy index (PFEI) based on contact force (CF) and pulse trains to test its role in the prediction of lesion depth in the ventricle.
Methods
The PFA procedure was delivered through a linear PFA catheter with switchable monopolar/bipolar discharge modes. The efficacy of monopolar and bipolar PFA was investigated with different CF levels (0-20g, 20-40g and 40-60g) and pulse trains (4×, 12×, 36× and 60×) in the potatoes and different anatomical sites of the ventricles, including ventricular free walls, interventricular septum, papillary muscles (PAPs) and valve annuli. The PFEI formula was created by using the MATLAB software. Finally, the efficacy of PFA was observed in one patient of premature ventricular contractions (PVCs) originating from the tricuspid valve annulus.
Results
First of all, in the ventricular myocardium and potato ablation experiments, monopolar PFA resulted in deeper lesions than the bipolar PFA among groups of different CF and pulse trains, but the lesion width in vivo was similar. For PAP ablation, there was no significant difference in lesion depth and width between monopolar and bipolar ablation (Depth: Monopolar: 4.053 ± 0.44 mm, Bipolar: 3.385 ± 0.19 mm, p = 0.214; Width: Monopolar: 7.000 ± 1.08 mm, Bipolar: 12.500 ± 3.33 mm, p = 0.167). For valve annuli ablation, both monopolar and bipolar PFA delivery can produce effective lesions in the sub-valvular myocardium via trans-leaflets approach, while radiofrequency ablation (RFA) cannot. Secondly, the CF and pulse train were positively correlated with lesion depth and width in vitro and in vivo under both monopolar and bipolar delivery, especially to the lesion depth. Based on these two parameters, we fitted the PFEI formula of monopolar ablation and bipolar ablation. The index PEFI was strongly linearly related to the actual lesion depth in swine (Monopolar ablation: r2 = 0.9137, p < 0.0001; Bipolar ablation: r2 = 0.8279, p < 0.0001).
Conclusions
Both of monopolar and bipolar PFA delivery can create effective ablation lesions in the ventricle, with deeper ablation lesions in the ventricular free wall and interventricular septum by monopolar PFA particularly. CF and pulse trains have synergistic effect on the ablation lesion size either in monopolar or bipolar PFA applications. Based on these two parameters, the PFEI formula can predict the lesion depth in the ventricle in both two discharge modes.PFA Catheter and PFA LesionsThe Prediction Accuracy of PFEI