PV Isolation Using a Spherical Array PFA Catheter: Preclinical Assessment and Comparison to Radiofrequency Ablation

Background: A multielectrode spherical array catheter capable of single-shot mapping and ablation has been introduced. Objectives: This study sought to compare the efficacy and safety of circumferential, linear, and focal ablation using either microsecond pulsed field (PF) and radiofrequency (RF) ablation in preclinical model. Methods: Under general anesthesia, a 122 gold-plated multielectrode array was introduced into the left atrium. Twenty-nine canines underwent isolation of two pulmonary veins (PVs), with linear and focal left atrial ablation with both RF (n = 12) and PF (n = 17). PF was also delivered within the superior vena cava and atop the esophagus in three swine. Animals were sacrificed acutely (immediately for RF [6 of 12] and 3 days for PF [6 of 17]) and the remaining (n = 17) at 14 to 30 days. Detailed necropsy and histopathology were performed. Results: All PVs were acutely (58 of 58) and durably (34 of 34) isolated and exhibited wide confluent lesions. Lesions were transmural for 97% to 100% of sections with depths of 2.5 to 3.4 mm and 2.5 to 3.5 mm in the acute and chronic cohorts, respectively. Linear and focal lesions displayed transmurality rates of 85% to 100% with depths of 3.5 millimeters to 4.2 millimeters in the acute cohort. In the chronic cohorts, linear lesions created with RF, PF+RF, and PF had no significant differences in depth (3.5 ± 1.8 millimeters, 4.0 ± 1.4 millimeters, and 3.9 ± 0.9 millimeters) or transmurality (83.3%, 100%, and 80%). Current of injury was seen on local unipolar electrogram immediately after PF and RF, and this occurred to a wider extent with PF. PF but not RF elicited bradycardia from ganglionated plexi stimulation. There were no instances of phrenic palsy, venous stenosis, esophageal damage, or thromboembolism. Conclusions: Circumferential, linear, and focal mapping and ablation can be achieved with this novel catheter using both PF and RF, with excellent efficacy and safety.