Original Article

Radiofrequency catheter ablation has become the standard ablation technique for the treatment of cardiac arrhyth-mias after direct current catheter ablation was abandoned, this was because of the high complication rate attributable to the generation of vapor globe, sparking, explosion, and pressure waves.1–4 Since its introduction, epicardial radiofrequency ablation is increasingly being performed for the treatment of ventricular arrhythmias because of ischemic and especially nonischemic cardiomyopathies.5 Radiofrequency causes heat damage to all tissue near the ablation site. Ablation near cor-onary arteries can therefore have hazardous adverse effects, such as coagulation of blood inside the vessel and vessel ste-nosis with subsequent myocardial infarction.6–8 In addition, the cooling effect of arterial and endocardial blood flow may limit lesion formation and success of the procedure.9,10 Editorial see p 573 Clinical Perspective on p 733 In recent years, irreversible electroporation has been pro-posed as a new ablation modality for cardiac arrhythmias.11–14 du Pré et al15 showed that epicardial electroporation ablation over coronary arteries, with a follow-up of 3 weeks, has a low risk of coronary damage and that the use of this tech-nique near or even on large coronary arteries is relatively safe. In addition, lesion formation by electroporation did not seem to be affected by the presence of arterial blood flow. We recently demonstrated that epicardial catheter ablation using 200 J electroporation applications can create extensive and deep myocardial lesions without significant damage to the coronary arteries after a 3-month follow-up period.16 The purpose of the present study is to investigate the rela-tionship between the magnitude of an epicardial electropora-tion application and lesion size