Abstract 3099: Reasons for Failure of Percutaneous Epicardial Catheter Ablation after Unsuccessful Endocardial Approach
Introduction: We describe cases of failed percutaneous epicardial (EPI) ablation of various types of arrhythmia for patients (pts) referred to our center after failed endocardial (ENDO) approach.
Methods: ENDO and EPI mapping and ablation were performed. Access to the pericardial space for EPI mapping and ablation was achieved with a percutaneous subxiphoid approach using a 17 gauge epidural needle. Mapping was performed using a Biosense Navistar catheter using CARTO electroanatomical mapping for guidance. Ablation was performed with any or all of the following: radiofrequency (RF) 4 mm and 8 mm tip catheters, closed-irrigation tip catheter, and cryoablation 4mm.
Results: A total of 80 pts underwent ENDO-EPI mapping and ablation, 57 for ventricular tachycardia (VT) and 23 for supraventricular tachycardia (SVT), primarily accessory pathways. Of these 80 patients, 9 pts had a failed ablation from both an ENDO and EPI approach. Reasons for ablation failure from an EPI approach: 2 were due to vicinity to phrenic nerve, 4 were considered to have a mid-myocardial substrate due to the fact that both ENDO and EPI lesions resulted in only brief transient termination of tachycardia, and 3 due to inability to deliver effective lesions from either low power or high impedance values. For the mid-myocardial and phrenic nerve cases, the use of EPI cryoablation 4 mm was attempted without success. EPI closed irrigation RF was used in two of the mid-myocardial cases without success.
Conclusion: While percutaneous EPI catheter ablation may be considered for pts in whom an ENDO approach has failed, in some pts the EPI approach may also be unsuccessful. Reasons for such failure include proximity to phrenic nerve, a mid-myocardial arrhythmia substrate, or inability to deliver effective lesions. In our preliminary experience 4 mm cryoablation and closed irrigation RF ablation were not effective alternatives. Whether other technologies such as open irrigation RF or larger tip cryoablation could overcome some of these limitations requires further study.