Modeling Analysis of Thermal Lesion Characteristics of Unipolar/Bipolar Ablation Using Circumferential Multipolar Catheter

The circumferential multipolar catheter (CMC) facilitates pulmonary vein isolation (PVI) for the treatment of atrial fibrillation by catheter ablation. However, the ablation characteristics of CMC are not well understood. This study uses the finite element method to conduct a comprehensive analysis of the ablation characteristics of multielectrode unipolar/bipolar (MEU/MEB) modes of the CMC. A three-dimensional computational model of the CMC, including blood, myocardium, connective tissue, lung, and muscle, was constructed. The method was validated by comparing the results of an in vitro experiment with the simulation. Both ablation modes could create contiguous effective lesions, but the MEU mode created a deeper and broader lesion volume than the MEB mode. The MEB mode had an overall higher average temperature field and allowed faster formation of the effective contiguous lesion. The lesion shape tended to be symmetric and spread downward and superficially in the MEU mode and MEB mode, respectively. Results from the simulation for validation agreed with the in vitro experiment. Different ablation trends of the MEU and MEB modes provide different solutions for specific ablation requirements in clinical applications. The MEU mode suits transmural lesion in thick tissue around pulmonary veins (PVs). The MEB mode profits fast and durable creation of circumferential PVI. This study provides a detailed performance analysis of CMC, thereby contributing to the theoretical knowledge base of application of PVI with this emerging technology.