Pulsed electric field ablation using an epi-endo electrode configuration yielded more translationally symmetric ablation volumes across the myocardial wall compared to penetrating electrodes, with a critical lethal field strength of 3 kV/cm.
Does electrode configuration affect the geometry of the ablated volume in cardiac tissue with twisted fiber anisotropy during pulsed electric field ablation?
Computational modeling and rabbit experiments suggest that an epi-endo electrode configuration provides more consistent pulsed electric field ablation volumes in atrial tissue compared to penetrating electrodes.
BACKGROUND: Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart. METHODS: We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium ("penetrating needles" configuration) and one circular electrode each on epi- and endocardium, opposing each other ("epi-endo" configuration). RESULTS: For thick tissues (10 mm) and moderate anisotropy ratio (a = 2), we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10) leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria) and higher anisotropy ratio (a = 10), the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist. CONCLUSIONS: These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the fiber orientation is not consistent across the atrial wall.
Xie et al. (Thu,) conducted a other in Cardiac ablation (n=12). Pulsed electric fields (epi-endo vs penetrating electrode configurations) was evaluated on Ablation volume geometry and critical field strength. Pulsed electric field ablation using an epi-endo electrode configuration yielded more translationally symmetric ablation volumes across the myocardial wall compared to penetrating electrodes, with a critical lethal field strength of 3 kV/cm.