Abstract

Purpose: Most modeling studies on radiofrequency cardiac ablation (RFCA) are based on limited-domain models, which means the computational domain is restricted to a few centimeters of myocardium and blood around the active electrode. When mimicking constant power RFCA procedures (e.g., atrial fibrillation ablation) it is important to know how much power is absorbed around the active electrode and how much in the rest of the tissues before reaching the dispersive electrode.

Methods: 3D thorax full models were built by progressively incorporating different organs and tissues with simplified geometries (cardiac chamber, cardiac wall, subcutaneous tissue and skin, spine, lungs and aorta). Other 2D limited-domain models were also built based on fragments of myocardium and blood. The electrical problem was solved for each model to estimate the spatial power distribution around the active electrode.

Results: From 79 to 82% of the power was absorbed in a 4 cm-radius sphere around the active electrode in the full thorax model at active electrode insertion depths of between 0.5 and 2.5 mm, while the impedance values ranged from 104 to 118 Ω, which were consistent with those found (from 83 to 103 Ω) in a 4 cm radius cylindrical limited domain model.

Conclusion: The applied power in limited-domain RFCA models is approximately 80% of that applied in full thorax models, which is equivalent to the power programed in a clinical setting.

摘要

目的：大多数关于射频心脏消融（RFCA）的建模研究都是基于有限域模型，这意味着计算域仅限于活动电极周围几厘米的心肌和血液。当模仿恒定功率的RFCA程序（例如，房颤消融）时，重要的是要知道在有源电极周围吸收了多少功率，在到达分散电极之前在其余组织中吸收了多少功率。

方法：通过逐步合并具有简化几何结构（心脏腔，心脏壁，皮下组织和皮肤，脊柱，肺和主动脉）的不同器官和组织，建立3D胸部完整模型。还基于心肌和血液的碎片建立了其他2D有限域模型。解决了每个模型的电气问题，以估算有源电极周围的空间功率分布。

结果：在全胸腔模型中，在有源电极插入深度为0.5至2.5 mm之间时，有源电极周围4 cm半径的球体中有79％至82％的功率被吸收，而阻抗值在104至118Ω之间，与在4 cm半径的圆柱有限域模型中发现的（从83到103Ω）一致。

结论：在有限域RFCA模型中施加的功率大约是在全胸腔模型中施加的功率的80％，这相当于在临床环境中编程的功率。