Beyond the endocardium: outcomes of epicardial ventricular tachycardia ablation guided by advanced imaging

Introduction

Conventional VT ablation typically combines endocardial and epicardial mapping. Advanced imaging (cardiac CT and MRI) can identify substrates predominantly epicardial, supporting a paradigm shift: epicardial-only ablation from the outset.

Purpose

To compare safety and effectiveness of initial epicardial-only versus combined endo-epicardial VT ablation guided by pre-procedural imaging in structural heart disease.

Methods

Retrospective single-centre study (2015–2025) including all patients undergoing VT ablation with epicardial access after systematic imaging (CT in all; MRI when feasible). Imaging findings guided procedural strategy: epicardial-only or combined approach. Procedures used subxiphoid access under general anesthesia, high-density epicardial mapping, and epicardial RF ablation when abnormal electrograms were confirmed.

Results

Fifty-four patients (59 procedures; mean age 62; 89% male; mean LVEF 36%) were analyzed: 80% dilated and 20% ischemic cardiomyopathy; 83% had ICDs. Indications: sustained VT (44%) or ICD shocks (56%), with 60% in electrical storm. Epicardial-only was performed in 31 procedures; combined in 28. Epicardial RF was delivered in 95% of cases; in 5% of all procedures, no abnormal substrate was found, exposing patients to unnecessary epicardial access. Median procedure time: 130 min; fluoroscopy: 17 min; RF: 33 min.

Periprocedural complications occurred in 29% (major 15%, including 1 death [1.7%]); tamponade requiring drainage: 5%. Major complications were less frequent with epicardial-only (10% vs 21%, p=NS).

During a mean follow-up of 2.2 years, VT recurrence occurred in 11 (22%) patients, 11 (22%) died, and 4 (9%) underwent heart transplantation. Kaplan-Meier survival at 1 and 4 years: 88% and 61%; VT-free survival: 88% and 60%. Outcomes did not differ significantly between groups.

Conclusion

Pre-procedural multimodality planning based on advanced imaging appropriately identifies patients in whom arrhythmogenic substrate requires epicardial access. Moreover, it delineates a subgroup in which an exclusively epicardial approach achieves durable arrhythmia control with an acceptable safety profile, comparable or superior to that obtained with the conventional combined strategy. This strategy may redefine patient selection and procedural planning for complex VT substrates.