Up to 35 sites will be recruited to participate in the registry. The registry uses a protocol designed to minimize potential risk to the patient and device. MRI compatible equipment will be required to monitor vital signs (non-invasive blood pressure monitoring, pulse oximeter, and single lead cardiac rhythm monitor) while performing scans on patients with implanted devices. Recommendations from the American Heart Association for performance of MR examination in patients with pacemakers or ICDs will be followed.