Creating Transmural, Linear Epicardial Ablation Lesions via a Non-surgical, Percutaneous, Subxyphoid, Electrogram-guided Approach

Surgical arrhythmia ablation techniques can achieve epicardial transmural lesions but require a combination of surgical access and endoscopic approaches. We sought to adapt a surgical ablation catheter to a percutaneous subxyphoid approach. The EpiSense nContact (Epi) is a surgical ablation catheter that contains a 3-cm ablation coil, an open irrigation system, and a suction mechanism to maintain tissue contact. Four sensing electrodes were added to the ablation coil to allow monitoring of electrograms. Six pigs were used for the study. A subxyphoid pericardial puncture was performed to advance a wire into the pericardial space. The subcutaneous tissue was dilated with a 165 cm angioplasty balloon to advance the Epi catheter into the pericardium without endoscopy or surgical tools. Manipulation was achieved by snaring and looping the wire over which the Epi catheter was advanced, or by positioning the wire across the transverse sinus to deliver atrial lesions. The catheter position in three dimensions was tracked with the NavX system. Adequacy of tissue contact was verified by monitoring electrograms recorded by the four Epi diagnostic electrodes. Epicardial ablations were performed in both atria (left atrial appendage, vein of Marshall, left atrial roof, right atrial roof and lateral right atrium) and both ventricles. Explanted hearts confirmed the accuracy of lesion locations as tracked by NavX and transmurality of the lesions. The Epi catheter delivers linear transmural lesions without surgical access or endoscopic approaches. Diagnostic electrodes in the Epi catheter allow for accurate tracking of catheter position in three dimensions and estimation of tissue contact.