Implantable Cardioverter Defibrillators (ICDs) provide a shock or pacing therapy to bring back a normal heart beat when a patient experiences a dangerous abnormal heart rhythm such as ventricular tachycardia (VT). ICDs are very successful in bringing back a normal heart beat when VT occurs, but they do not prevent further dangerous heart rhythms from occurring. This study is designed to determine the best way to manage patients who have an ICD and who continue to have episodes of VT. There are two methods for treatment the VT: 1) Ablation, and 2) Medication.