Catheter ablation of ventricular tachycardia via the coronary veins.

Ventricular arrhythmias, either idiopathic or those associated with organic heart diseases, may originate from the epicardial side of the ventricular myocardium. Therefore, mapping and ablation via the coronary venous system offers a convenient, feasible, and effective option in such cases, considering the convenience of the epicardial location of the coronary venous system. Among epicardial idiopathic ventricular arrhythmias, the left ventricular summit is by far major region of interest closely associated with the coronary venous system. In this setting, the great cardiac vein/anterior interventricular vein or their tributaries serve as a convenient and practical route for the epicardial or intramural mapping of ventricular arrhythmias originating from this region, via endocardial access through the coronary sinus. In limited cases, where these veins are incidentally close enough to the arrhythmogenic focus and distant enough from the left coronary arteries, radiofrequency or ethanol ablation via these veins is also feasible and effective. Devices and techniques have been improved to facilitate transvenous epicardial and intramural mapping and ablation. Wide individual variations exist in terms of three-dimensional orientation of these veins relative to the left ventricular summit, coronary arteries, pulmonary root, and left atrial appendage. Therefore, discerning case-specific anatomy through careful review of periprocedural image findings is fundamental for estimating feasibility of transvenous epicardial procedures. In this review, comprehensive anatomy of the coronary venous system around the left ventricular summit as well as current clinical implications are summarized from the electrophysiologist's perspective.