Epicardial approach for cardiac electrophysiology procedures

Since its introduction over two decades ago, percutaneous epicardial procedures have become well-adopted by cardiac electrophysiologists, most commonly for catheter ablation of cardiac arrhythmias as well as left atrial appendage closure. The percutaneous epicardial approach has also been utilized for cardiac pacing and drug delivery. But still, its most common usage is for the treatment of intramural and subepicardial substrates that give rise to ventricular tachycardia, particularly in patients with nonischemic cardiomyopathy. In fact, subxiphoid, percutaneous epicardial mapping and ablation have emerged as an important adjunct and in some cases the preferred strategy for characterizing and treating certain types of ventricular arrhythmias. Herein, we will review the indications and rationale for various epicardial procedures. Additionally, we will explore the anatomy of the pericardium as well as the frequently-used epicardial access techniques. We will further examine the optimal approaches and methodologies for epicardial mapping and ablation and the impact of epicardial fat. We will also discuss the epicardial technique for left atrial appendage closure for the purpose of embolic stroke risk reduction. Finally, we will consider the potential for various complications in the setting of epicardial procedures along with their risk factors and discuss strategies to mitigate such adverse events.