Endo-epicardial Transmural Lesion Formation Utilizing Multipolar Radiofrequency Ablation.

Background: Conventional unipolar radiofrequency catheter ablation (RFCA) is limited by maximal lesion depths that fail to eliminate VTs with deep mid-myocardial critical components. The use of multipolar mapping catheters as an active part of the ablation circuit may provide a solution to these limitations.

Objective: To evaluate a novel endo-epicardial multipolar-RFCA technique for creating transmural lesions in an in-vivo porcine model.

Methods: Two catheter configurations were evaluated: (1) standard bipolar configuration with a 3.5-mm irrigated-tip catheter paired with an 8-mm non-irrigated-tip catheter. (2) Multipolar configuration with a 3.5-mm irrigated-tip catheter paired with a multipolar mapping catheter. In both configurations, the 3.5-mm irrigated-tip catheter was positioned on the endocardial surface of the LV with the corresponding catheter positioned perpendicularly on the epicardial surface.

Results: The study included 10 subjects with a total of 30 lesions created using 6 different sets of catheter configurations and ablation parameters. Histopathological analysis revealed an average lesion depth was 10.6 ± 3.1 mm (range: 5-17 mm), corresponding to a lesion depth/tissue thickness ratio of 93.5 ± 12%. 20 out of 30 lesions (67%) achieved transmurality. No safety complications such as steam pops, fistulas, perforations, or tamponades were observed.

Conclusion: Endo-epicardial multipolar radiofrequency ablation can be performed effectively and safely using a multipolar mapping catheter as the return electrode in the epicardial space. Lesions created were voluminous with a high degree of transmurality, with no complications related to the application of radiofrequency recorded. This catheter configuration may present a novel solution to rapidly identify and target ventricular arrhythmias arising from the mid-myocardium.