Low-energy (360 J) radiofrequency catheter ablation using moderate power - short duration: proof of concept based on in silico modeling

Background Pilot clinical studies suggest that very high power-very short duration (vHPvSD, 90 W/4 s, 360 J energy) is a feasible and safe technique for ablation of atrial fibrillation (AF), compared with standard applications using moderate power-moderate duration (30 W/30 s, 900 J energy). However, it is unclear whether alternate power and duration settings for the delivery of the same total energy would result in similar lesion formation. This study compares temperature dynamics and lesion size at different power-duration settings for the delivery of equivalent total energy (360 J). Methods An in silico model of radiofrequency (RF) ablation was created using the Arrhenius function to estimate lesion size under different power-duration settings with energy balanced at 360 J: 30 W/12 s (MPSD), 50 W/7.2 s (HPSD), and 90 W/4 s (vHPvSD). Three catheter orientations were considered: parallel, 45 degrees, and perpendicular. Results In homogenous tissue, vHPvSD and HPSD produced similar size lesions independent of catheter orientation, both of which were slightly larger than MPSD (lesion size 0.1 mm deeper, 0.7 mm wider, and similar to 25 mm(3) larger volume). When considering heterogeneous tissue, these differences were smaller. Tissue reached higher absolute temperature with vHPvSD and HPSD (5-8 degrees C higher), which might increase risk of collateral tissue injury or steam pops. Conclusion Ablation for AF using MPSD or HPSD may be a feasible alternative to vHPvSD ablation given similar size lesions with similar total energy delivery (360 J). Lower absolute tissue temperature and slower heating may reduce risk of collateral tissue injury and steam pops associated with vHPvSD and longer applications using moderate power.

Automated summary

This study compares the temperature dynamics and lesion size at different power-duration settings for the delivery of equivalent total energy. The results show that in homogeneous tissue, high power-short duration and moderate power-short duration produce similar lesion sizes, slightly larger than moderate power-long duration. In heterogeneous tissue, these differences are smaller. Additionally, high power-short duration leads to higher absolute tissue temperature, which may increase the risk of collateral tissue injury and steam pops.