This protocol outlines a prospective study evaluating safety and clinical outcomes of magnetic resonance imaging (MRI) examinations performed on patients with cardiac implantable electrical devices (CIEDs) including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). This prospective study aims to improve the evidence base regarding this common clinical scenario. Specifically, the investigators aim to address whether results of MRI in PM/ICD patients affect physician decision making related to clinical management strategy and planning treatment interventions. Further, this study will evaluate whether the results of MRI in these patients affects patient outcomes related to survival and adverse events during or after MRI scanning.

MRI is the preferred imaging modality for both acute and elective evaluation of many conditions. For example, for many diseases of the central nervous system, no other imaging modality provides the requisite soft tissue resolution to support critical care elements such as neurosurgical planning or assessment of intracranial malignancies.

Historically, MRIs were considered contraindicated for patients with CIEDs including PMs and ICDs. However, studies have demonstrated very high utilization of MRIs among patients eligible for CIEDs. In many cases, alternative imaging is either insufficient or, as with CT-myelography, poses substantial risks or procedural hurdles that may be less favorable than the potential risks of an MRI.

In recent years, a growing literature has suggested that MRIs can be performed safely in the setting of CIEDs if certain precautions are taken. Additionally, guidance documents have been released by professional societies including the American Heart Association (AHA) and the American College of Radiology (ACR) outlining recommended safety measures that can be taken to minimize risk and maximize benefit for patients in need of imaging. However, there are fewer data on performing MRIs in pacemaker-dependent patients with ICDs, who were excluded from the largest published study as well as the MagnaSafe Registry. Thus, demonstrating the safety and clinical utility of performing MRIs in this context is of high importance.

In response to urgent clinical considerations, Beth Israel Deaconess Medical Center has established a clinical protocol to provide safe MRIs in cases of compelling clinical indications, with close supervision and oversight from Radiology and Cardiac Electrophysiology staff. Thus, the investigators now propose a prospective study to evaluate safety and clinical outcomes for patients treated under this clinical protocol.

Specifically, this study proposes to perform a prospective clinical trial in patients with CIEDs that have a clinical need for MRI as outpatients to determine:

1. Safety according to the incidence rates of acute major and minor adverse events according to pre-specified definitions.
2. Clinical outcomes and scan utility affecting patients' survival and quality of life and treatment, including acute and longitudinal changes in device parameters, the need for system revision, and proportion of MRI findings influencing clinical management including medical or surgical interventions, and diagnostic or prognostic changes.

Inclusion Criteria:

• Patients have a medically/clinically indicated need for an MRI

• Patients with a non-MRI conditional pacemaker and/or ICD implanted after the year 2000

• Patients are willing and able to sign consent and HIPAA authorization or an authorized representative of the patient is willing to sign consent for the patient

  *The following factors are considered relative contraindications to the clinical protocol at BIDMC, and will similarly be considered exclusion criteria for the study. Exceptions on a case-by-case basis for circumstances of dire, life-threatening need may be considered.

• Leads implanted <6 weeks prior to the MRI

• Presence of any capped/abandoned leads

• Presence of nontransvenous epicardial leads

Exclusion Criteria:

• Other contraindications to MRI (e.g. other non-MRI-conditional implants)
• Pacemaker or ICD implanted prior to the year 2000
• Leads and/or generator implanted within 6 weeks of the proposed MRI
• CIED that is FDA approved as MRI conditional
• Pregnant women

This is a prospective observational study of patients with a cardiac implantable electronic device (CIED) referred for a clinicially indicated MRI.