The Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy ( MADIT-CRT ) showed that early intervention with cardiac-resynchronization therapy with a defibrillator ( CRT-D ) in patients with an electrocardiographic pattern showing left bundle-branch block was associated with a significant reduction in heart-failure events over a median follow-up of @ years , as compared with defibrillator therapy alone .