The implanted CRM device will have shock therapy and rate sensor temporarily deactivated or placed in magnet mode during the time the IMED-4 is activated. The IMED-4 will be activated for a time not to exceed 15 minutes. During the time the IMED-4 is active, the CRM device programmer will print the voltage sensing of the implanted lead in real-time. The printout will be examined for the presence of far-field sensing artifacts.