Introduction: The epicardial approach for ventricular tachycardia (VT) ablation is sometimes necessary but high-risk procedure. While most VTs can be successfully treated with endocardial ablation, certain cases, especially those associated with arrhythmogenic and particularly non-ischemic cardiomyopathies, require epicardial mapping and ablation for effective treatment. The use of epicardial approach, however, poses procedural risks, such as injury to coronary arteries, phrenic nerves, subdiaphragmatic vessels, and accidental puncture of the right ventricle. To enhance the safety and efficacy of this approach, intentional puncture of coronary venous branches with epicardial carbon dioxide (EPI CO₂) insufflation has emerged as a valuable technique to facilitate pericardial space visualization and access. In this technique, a coronary sinus branch is cannulated using a diagnostic JR4 coronary catheter, followed by intentional perforation of the branch using an angioplasty wire (Conquest PRO). A microcatheter (Corsair PRO, Asahi Intecc, Japan) is then positioned over the wire into the pericardial space, allowing CO₂ insufflation. This enables direct visualization of the anterior pericardial space, facilitating safer subxiphoid puncture. (1-3)

Case report: 36-year-old female with arrhythmogenic cardiomyopathy and ventricular tachycardia, previously unresponsive to medical therapy, underwent combined endocardial and epicardial ablation. She had a history of ventricular fibrillation during childbirth in 2020. The procedure, performed under deep sedation with midazolam, propofol, and fentanyl, involved epicardial ablation using an 3D mapping/ablation catheter (Navistar SmartTouch ST/SF, Biosense Webster), with phrenic nerve stimulation monitoring and coronary angiography. After the ablation, VT could no longer be induced. At the end of the procedure, intrapericardial corticosteroids were administered to prevent pericarditis and minimize its symptoms.

Conclusion: Proper pre-procedural planning and understanding of potential complications are essential for reducing the risks associated with the epicardial approach. Techniques such as EPI CO₂ insufflation represent significant advancements in improving the safety and precision of percutaneous epicardial access, especially for complex VT cases.