Epicardial ablation of ventricular tachycardia is a relatively new technique for ablating abnormal heart rhythms that originate close to or on the surface of the heart (epicardium).  In most cases VT originates from abnormal heart tissue that lies on the inner surface or in the middle of the heart muscle so ablation from the inside is successful.  Occasionally the abnormal heart tissue is near the outer surface and so ablating the outer surface can be more successful.  The procedure is performed by introducing the ablation catheter via a small puncture in the skin into the space around the surface of the heart.  The puncture is usually located at the lower end of the breastbone.  In most cases ablation is also performed on the inside of the heart so a dual approach is used.