According to the research, cardiomyocytes in the ablation area were replaced by fibroblasts and there was no damage outside the ablation zone. Our results show that pulmonary venous isolation using the biphasic asymmetric discharge mode is safe, durable, effective, and causes no damage to other tissues.
Pulsed field ablation (PFA), also known as irreversible electroporation, has been applied to cardiac ablation in recent years (1–3). PFA is a non-thermal ablative modality. It is used to treat atrial fibrillation and does not cause damage to other tissues such as the esophagus and nerves, because the threshold for cardiomyocytes is the lowest of any other tissue.
Based on our previous cell experiment, PFA with biphasic asymmetric pulses was carried out in 12 Bama miniature pigs. Gross examination and histological investigation were used to evaluate the lesion persistence and safety of PFA at the 7th and 30th day after pig PFA operation. Moreover, PFA with biphasic asymmetric pulses was carried out in 2 dogs, and electroanatomic mapping was used to display the lesion area. Our results would be used to help to make a treatment plan for clinical trials in the future.
In the present study, the ablation results were recorded at 1 and 4 weeks, and the lasting effectiveness and safety of the biphasic asymmetric PFA system in the treatment of atrial fibrillation were verified, ensuring the safety of future clinical trials using the same system. In the pig experiment (Group A&B), there was no ventricular arrhythmia at any time during the operation, and the behavioral activities, mental status, appetite, and feed intake of the pigs returned to normal after the operation. We examined the near-ablation zone, including the vagus nerve, lung, trachea, and esophagus. A pathological analysis of the ablation zone performed at 1 and 4 weeks showed that all targeted parts produced complete transmural lesions and maintained good safety.At 4 weeks after PFA, fibroblasts had replaced the original cardiomyocytes and PFA had not destroyed the intercellular connection, which was conducive to the maintenance of the tissue structure. There was no thromboembolism, intracardiac injury, or acute or chronic collateral tissue injury after ablation.Consistent with our previous in vitro experiments (18), the present results further proved that the biphasic asymmetric pulse mode and PFA system used in the present study had good safety and produced effective lesions.
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