Advances in Epicardial Access for Ventricular Tachycardia Ablation: From Historical Techniques to Carbon Dioxide...

Epicardial access is often required for effective catheter ablation of ventricular tachycardia (VT) originating from the epicardium, especially in patients with non-ischemic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), and cardiac sarcoidosis. Traditional subxiphoid access using large-bore needles remains effective but carries substantial procedural risks, including right ventricular (RV) puncture, coronary artery injury, and injury to intra-abdominal organs. These risks are amplified in patients with prior cardiac surgery, obesity, and distorted anatomy. To mitigate these challenges, several technical advancements have been introduced, including the needle-in-needle (micropuncture) technique and the SAFER approach using RV angiography during apnea. However, these methods do not fully overcome the inherent limitation of minimal separation between the pericardial layers at the time of pericardial puncture. Carbon dioxide (CO₂) insufflation into the pericardial space is a recently developed technique that can temporarily separate the parietal and visceral pericardium for safer epicardial access. Coronary venous exit for CO₂ has demonstrated safety and efficacy, as confirmed in the multicenter Epi-CO₂ Registry. Further advances include the use of radiofrequency (RF)-assisted trans-right atrial appendage (RAA) perforation for CO₂ insufflation. In this comprehensive review, the advancement of epicardial access is discussed from the early era to contemporary techniques, especially regarding CO₂ insufflation, including its pitfalls and the future direction of this technique.