ABSTRACT
BACKGROUND: Pulsed field ablation (PFA) leads to cell death by irreversible electroporation. There are limited data about PFA lesion characteristics in the ventricle, particularly in the presence of myocardial scar. OBJECTIVES: This study sought to evaluate the lesion characteristics of PFA and radiofrequency energy (RFA) in healthy and infarcted left ventricular (LV) myocardium in swine. METHODS: Swine (n = 10) underwent either: 1) 120-minute left anterior descending coronary artery balloon occlusion myocardial infarction and survived for 6 to 8 weeks (n = 8); or 2) served as healthy control subjects (n = 2). PFA or RFA was delivered to the LV endocardium in regions of healthy myocardium or scar identified with electroanatomical mapping. Bipolar, biphasic PFA was delivered for 2.5 seconds × 4 applications/site using 2 different catheters: linear quadripolar (FOCAL) or multispline 8-pole catheter (BASKET). Gross and histologic measurements of lesion size were performed. RESULTS: In the PFA group, 21 lesions were delivered to healthy LV and 20 to areas of scar. Overall, there was no significant difference in lesion depth between catheter groups (FOCAL linear vs BASKET; P = 0.740), whereas lesion width was greater for BASKET (10.6 ± 2.4 mm vs 13.3 ± 3.3 mm; P = 0.007). In myocardial scar, lesion depth was not significantly different between PFA catheters (P = 0.235). However, lesion depth for PFA was greater than for RFA (PFA vs RFA; 6.1 ± 1.7 mm vs 3.8 ± 1.7 mm; P = 0.005). CONCLUSIONS: PFA allows rapid, safe, and effective ablation of surviving islands of myocardium within and around infarcted LV substrate. This technology holds promise for treating infarct-related ventricular tachycardia in humans.
