ProMRI Study of the Entovis Pacemaker System (Phase B)

Inclusion Criteria: The following initial inclusion criteria must be met for a subject to be enrolled and considered for the MRI-procedure: * Age greater than 18 years * Able and willing to complete MRI testing * Able to provide written informed consent * Available for follow-up visit at the study site * Implanted with a pacemaker system consisting only of an Entovis pacemaker (DR-T, SR-T) and one or two Setrox S 53 or Setrox S 60 pacemaker lead(s). (No leads other than Setrox S (53 or 60 cm) leads may be implanted. This includes lead extensions or abandoned leads in the subject.) * Pacemaker implanted pectorally * All pacemaker system components implanted, repositioned, or exchanged at least 5 weeks prior to enrollment * Underling rhythm identifiable during sensing test * All pacing thresholds are measureable and are less than or equal to 2.0 V @0.4 ms * Absence of phrenic nerve stimulation at 4.8V @ 1.0 ms * Pacing impedance is between 200 and 1500 ohm * Able and willing to use the Cardio Messenger At the pre-MRI procedure, the following procedure-related criteria must be met for the subject to undergo the MRI scan: * Absence of phrenic nerve stimulation at 4.8V @ 1.0 ms •\|pacing threshold at Pre-MRI follow-up - pacing threshold at baseline\| ≤ 0.5 V * All pacing thresholds are measureable and are ≤ 2.0 V @ 0.4 ms * The pacemaker system has been implanted for at least 6 weeks. * Subject did not have a pacemaker or lead explant, exchange or reposition in the previous 6 weeks. * All lead impedances are between 200 and 1500 ohm. * Battery status is at least 30% of capacity Exclusion Criteria: * Enrolled in any other clinical study * For pacemaker systems that include an atrial lead, subjects with either * Persistent atrial arrhythmia (lasting longer than 7 days or requiring cardioversion) * Permanent atrial arrhythmia * Life expectancy of less than three months * Pregnancy * Cardiac surgery expected in the next three months Implanted with other medical devices that may interact with MRI, such as: * abandoned pacemaker/ICD leads * lead extensions * mechanical valves * other active medical devices * non-MRI compatible devices * other metallic artifacts/components in body that may interact with MRI