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CA-527-01 THE EFFECT OF PULSED FIELD ELECTROPORATION ON VENTRICULAR SCAR IN PRE-CLINICAL MODEL OF MYOCARDIAL INFARCTION

      Background

      Pulsed-field ablation (PFA) is a rapid and nonthermal energy with higher selectivity to myocardial tissue in comparison to radiofrequency ablation. While it produces well-demarcated lesions in healthy ventricles, its effect on clinically relevant scarred myocardium has not been well studied.

      Objective

      To examine the effect PFA on heterogenous ventricular scar in a preclinical model of healed myocardial infarction.

      Methods

      In 4 swine, myocardial infarction was created by balloon occlusion of the left anterior descending artery. After a survival period of 8-10 weeks, the LV endocardium was mapped using an 8F bidirectional deflectable catheter with an expandable conductive lattice electrode (Sphere-9™, Affera Inc.) and a compatible electroaantomical mapping system as shown in Figure 1. PFA (biphasic waveform of ±1.3-2.0 kV) was delivered at infarct border-zone sites identified by reduced bipolar voltage (<1.5mV) and abnormal electrograms (Fractionated near field potentials). Tissue capture during pacing (10mV/2msec) was examined before and after ablation at each site. Animals were survived for an additional 48 hours before histopathological analysis.

      Results

      A total of 11 focal PFA applications were delivered in infarct border-zone sites (2-3 per heart). PFA resulted in elimination of near-field potentials and loss of tissue capture with pacing. In infarct border-zones comprising of viable islands of myocardium separated by collagen, fat, and calcium deposition, PFA produced well-demarcated lesions (Figure 2). Lesion width was 16.5±1.8, lesion depth was 6.6±1.5, and 72.8% of all lesions were transmural. Importantly, PFA successfully ablated viable myocardium both within the infarct and epicardial to the infarct, affecting viable myocardium separated from the energy source by scar tissue.