Differential effect of high-frequency electroporation on myocardium vs. non-myocardial tissues

Pulsed-field ablation (PFA) is an emerging non-thermal ablation method based on the biophysical phenomenon of electroporation. Data on PFA cardiac selectivity nature and tissue-specific thresholds are lacking. We aim to compare the in vivo differential effect of high-frequency irreversible electroporation (HF-IRE) protocols on various tissues.

Twenty-three Sprague-Dawle rodents were allocated into three different protocols of 300, 600, and 900 V, respectively, while delivering twenty 100 µs bursts of a 150 kHz biphasic square wave to five tissues; cardiac muscle, skeletal muscle, liver, carotid artery and sciatic nerve. Lesions were evaluated quantitatively by histologic analysis and by morphometric evaluation. There were eight, seven and eight animals in the 300, 600, and 900 V protocols, respectively. High-frequency electroporation protocols showed a graded effect on myocardial tissue with larger lesions in the 900 V protocol compared with the other two protocols as demonstrated by width (P = 0.02), length (P = 0.01) and fibrosis ratio (P = 0.001). This effect was not observed for other tissues with attenuated degree of damage. No damage to the carotid artery was observed in all protocols. Partial damage to the sciatic nerve was observed in only two samples (25%) in the 600 V group and in one sample (14.3%) in the 900 V group.

Electroporation effect is tissue-specific such that myocardium is more prone to electroporation damage compared with neural and vascular tissues. Our results suggest no neural or vascular damage with using a low-amplitude HF-IRE protocol. Further investigation is warranted to better identify other tissue-specific thresholds.