title: A simulation study to compare the phase-shift angle radiofrequency ablation mode with bipolar and unipolar modes in creating linear lesions for atrial fibrillation ablation.
abstract: Purpose In pulmonary veins (PVs) isolation (PVI), radiofrequency (RF) energy is often used to create a linear lesion for blocking the accessory conduction pathways around PVs. By using transient finite element analysis, this study compared the effectiveness of phase-shift mode (PsM) ablation with bipolar mode (BiM) and unipolar mode (UiM) in creating a continuous lesion and lesion depth in a 5-mm thick atrial wall. Materials and methods Computer models were developed to study the temperature distributions and lesion dimensions in atrial walls created through PsM, BiM, and UiM. Four phase-shift angles - 45°, 90°, 135°, and 180° - were considered in PsM ablation (hereafter, PsM-45°, PsM-90°, PsM-135°, and PsM-180°, respectively). Results At 60 s/30 V peak value of RF voltage, UiM and PsM-45° did not create an effective lesion, whereas BiM created a lesion of maximum depth and width approximately 1.01 and 1.62 mm, respectively. PsM-135° and PsM-180° not only created transmural lesions in 5-mm thick atrial walls but also created continuous lesions between electrodes spaced 4 mm apart; similarly, PsM-90° created a continuous lesion with a maximum depth and width of nearly 4.09 and 6.12 mm. Conclusions Compared with UiM and BiM, PsM-90°, PsM-135° and PsM-180° created continuous and larger lesions in a single ablation procedure and at 60 s/30 V peak value of RF voltage. Therefore, the proposed PsM ablation method is suitable for PVI and linear isolation at the left atrial roof for treating atrial fibrillation.
authors.affiliation: a Electronic Engineering Department , Fudan University , Shanghai ;
authors.forename: Shengjie
authors.initials: S
authors.lastname: Yan
authors.affiliation: a Electronic Engineering Department , Fudan University , Shanghai ;|b Shanghai Engineering Research Centre of Assistive Devices , Shanghai ;|c Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai , Fudan University , Shanghai , China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wu
authors.affiliation: a Electronic Engineering Department , Fudan University , Shanghai ;
authors.forename: Weiqi
authors.initials: W
authors.lastname: Wang
mesh_terms: D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003198:Computer Simulation; D020342:Finite Element Analysis; D006325:Heart Atria / Q000601:surgery; D008954:Models, Biological; D013696:Temperature
keywords: Continuous lesion; RF ablation; lesion depth; phase-shift angle; transient finite element method model; transmural lesion