Factors Influencing Lesion Titration in a Monopolar Pulsed-Field Ablation Point Catheter: A Preclinical Study

Despite the rise of pulsed-field ablation (PFA), predicting and titrating lesion geometry remains challenging. This study aimed to find modifiable parameters that can accurately and repeatedly predict focal PFA lesions across a range of dimensions and to develop a model to predict lesion geometry.

An in vivo study was performed in 9 swine using an investigational dual-energy contact-force focal catheter with local impedance. Ablations were performed endocardially in the right and left ventricles using settings specifically selected to provide a wide range of lesion dimensions. Predefined PFA applications (1, 2, or 4) were delivered while maintaining different contact-force values (5-45 g). Four different voltages were used (1.0, 1.4, 2.0, and 2.2 kV). Following a 1-week survival period, the animals were euthanized for histopathologic examination.

In the study characterization data set, a total of 78 PFA lesions were analyzed. Lesion depth ranged from 1.4 mm to 12.3 mm, while lesion width ranged from 3.3 mm to 21.2 mm. All 3 tested parameters-contact force, number of applications, and voltage-demonstrated a positive linear correlation with lesion depth (P<0.01). The proposed formula (Focal FARAPULSE Index Model) showed a strong positive correlation with lesion depth (R=0.83; P<0.0001) and lesion width (R=0.76; P<0.0001). A perpendicular catheter orientation was correlated with deeper lesions than a parallel orientation. No ST-segment elevations or sustained ventricular arrhythmias were observed.

Our findings demonstrate that PFA can be effectively titrated and predicted using the Focal FARAPULSE Index Model to create lesions of varying depths (1-12 mm), with these results being specific to the proprietary waveform and catheter used.