Catheter Ablation of Ventricular Arrhythmias Arising from the Left Ventricular Summit.

The left ventricular summit is a common site of origin of idiopathic ventricular arrhythmias. These arrhythmias are most commonly ablated within the coronary venous system or from other adjacent structures, such as the right ventricular and left ventricular outflow tract or coronary cusp region. When ablation from adjacent structures fails, a percutaneous epicardial approach can be considered, but is rarely successful in eliminating the arrhythmias due to proximity to major coronary vessels and/or epicardial fat.