Endoepicardial transmural lesion formation utilizing multipolar radiofrequency ablation.

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

Objective: This study aimed to evaluate a novel endoepicardial multipolar RF catheter ablation 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 and (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 left ventricle 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. Histopathologic analysis revealed an average lesion depth of 10.6 ± 3.1 mm (range 5-17 mm), corresponding to a lesion depth to tissue thickness ratio of 93.5% ± 12%. Notably, 20 of 30 lesions (67%) achieved transmurality. No safety complications such as steam pops, fistulas, perforations, or tamponades were observed.

Conclusion: Endoepicardial multipolar RF 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 RF recorded. This catheter configuration may present a novel solution to rapidly identify and target ventricular arrhythmias arising from the midmyocardium.