Myocardial lesion size after epicardial electroporation catheter ablation after subxiphoid puncture

Background: Irreversible electroporation is a promising nonthermal ablation modality able to create deep myocardial lesions. We investigated lesion size after epicardial electroporation catheter ablation with various energy levels after subxiphoid pericardial puncture.

Methods and results: In six 6-month-old pigs (60-75 kg), a custom deflectable octopolar 12-mm circular catheter with 2-mm ring electrodes was introduced via a deflectable sheath after pericardial access by subxiphoid puncture. Nonarcing, nonbarotraumatic, cathodal 50, 100, and 200 J electroporation applications were delivered randomly on the basal, mid and lateral left ventricle. After 3-month survival, myocardial lesion size and degree of intimal hyperplasia of the coronary arteries were analyzed histologically. Five animals survived the follow-up without complications and 1 animal died of shock after the subxiphoid puncture. At autopsy, whitish circular scars with indentation of the epicardium could be identified. Average lesion depths of the 50-, 100-, and 200-J lesions were 5.0±2.1, 7.0±2.0, and 11.9±1.5 mm, respectively. Average lesion widths of the 50-, 100-, and 200-J lesions were 16.6±1.1, 16.2±4.3, and 19.8±1.8 mm, respectively. In the 100- and 200-J cross sections, transmural left ventricular lesions and significant tissue shrinkage were observed. No intimal hyperplasia of the coronary arteries was observed.

Conclusions: Epicardial electroporation ablation after subxiphoid pericardial puncture can create deep, wide, and transmural ventricular myocardial lesions. There is a significant relationship between the amounts of electroporation energy delivered epicardially and lesion size in the absence of major adverse events.