Magnetic Resonance Imaging and Radiation Exposure in Patients with Cardiovascular Implantable Electronic Devices
Key Points
Key Points
- MRI generates static and gradient magnetic fields as well as RF energy. The potential interactions between CIEDs and electromagnetic interference from MRI include the following:
- Magnetic field-induced force and torque due to ferromagnetic materials: CIED generator movement is extremely unlikely due to confinement in the subcutaneous tissues.
- Leads do not contain any significant ferromagnetic materials to cause movement in a magnetic field.
- Gradient magnetic field-induced electrical current: Gradient magnetic fields can induce current in conductive wires within the field that could lead to myocardial capture and potentially lead to atrial or ventricular arrhythmias.
- Heating and tissue damage: RF fields can lead to nonconditional CIED component heating and subsequent thermal damage to the surrounding tissue (functional ablation). Changes in sensing or capture thresholds can occur as a result of tissue damage near lead electrodes.
- Effects on reed switch activity: The reed switch is a feature that permits programming of the device by placement of a magnet. Magnetic fields might therefore affect the reed switch activity of a nonconditional CIED, leading to asynchronous pacing and inhibition of tachycardia therapies.
- Electrical reset: High-energy electromagnetic interference (EMI) can lead to electrical or power-on-reset, a backup demand mode, wherein pacing might be inhibited and tachyarrhythmia therapy activated.
- Power-on-reset parameters vary by vendor and type of CIED (See Tables 1 and 2), and can include reset of pacing polarity to unipolar.
- Inhibition of pacing function due to oversensing of MRI-generated signals or pacing at an output below threshold (bipolar or unipolar) in a pacemaker (PM)-dependent patient might occur in the setting of power-on-reset and must be recognized to prevent catastrophic consequences.
- Additionally, battery status can be affected, particularly for CIEDs that are near an elective replacement interval (ERI), which could result in unreliable function.
- Inappropriate function and therapies: EMI from RF energy pulses or rapidly changing magnetic field gradients might cause oversensing that can lead to inappropriate inhibition of demand pacing and possibly asystole in a pacing-dependent patient, or induction of therapies such as inappropriate shocks in a patient with an implantable cardioverter defibrillator (ICD). Other inappropriate tracking or programming changes can occur.
- Magnetic field-induced force and torque due to ferromagnetic materials: CIED generator movement is extremely unlikely due to confinement in the subcutaneous tissues.
- These effects are influenced by various factors, including magnet field strength, RF power, position of the patient and the CIED within the MRI bore, CIED characteristics, and the size of the patient.
Device Parameters
...evice Parameter...
...ble 1. Programmed Parameters for PMs...
...mmed Parameters for ICDs During Power-O...
...ood and Drug Administration (FDA)-Appro...
...finitions of CIED Systems in Relation to MRIHavi...
Management of Patients with a CIED Referred for MRI
...t of Patients with a CIED Referred for MRI...
...le 5. Recommendations and Protocol...
...conditional devices should be cons...
...a patient with an MR conditional system should...
...ended for patients with an MR conditional syste...
...d for patients with an MR conditional s...
...scitative efforts and emergency treatments...
...mmended for patients with an MR condi...
...easonable to perform an MR scan on a patient with...
...mmendations for the Decision to Perfo...
...is reasonable for patients with an MR non...
...easonable to perform an MR scan imme...
...or patients with an MR nonconditional CI...
...able 7. Recommendations for the Manageme...
...is recommended for the patient wit...
...tor/monitor (with external pacing function) a...
...nded that continuous MR conditional...
...is recommended that personnel with the skill to...
...with an MR nonconditional CIED who are pacing-d...
...ith an MR nonconditional CIED who are not pacing-...
...ended that for the patient with an...
...tachyarrhythmia detections for patient...
...e MR-responsible physician who is accou...
...d that ECG and pulse oximetry monitor...
...ve efforts and emergency treatments that involv...
...nt with an MR nonconditional CIED who is not p...
...nable to program patients with an MR nonconditiona...
...re 1. Management Algorithm...
...e 2. Checklist for MRI Safety in the Setting...
...ble 8. Implantable Loop Reco...
...is recommended that prior to MRI scanning p...
...ning of MR conditional ILRs should...
...able 9. Employee Sa...
...s recommended that the MR suite has a...
Management of Patients with a CIED Undergoing CT Imaging
...nagement of Patients with a CIED Undergoing CT...
...0. Recommendations for the Management of P...
...s recommended that patients with a CIED...
...reasonable to exclude the device from...
...be reasonable to monitor patients who h...
...dary Neutron-Producing Radiation in...
...e 12. Recommendations and Protocol for...
...or to the initiation of radiation treatment...
...on-producing treatment is preferred...
...y complete CIED evaluations for patients undergoi...
...evaluation should be performed at t...
...al and voice contact is recommended during each...
...ocation is recommended if its curr...
...be reasonable to perform a complete...
...is NOT recommended for devices receivi...
Management of Patients with a CIED Undergoing Radiation Therapy
...ent of Patients with a CIED Undergoing...
...Checklist for Performance of Radiation...
...igure 4. CIED Management for Radiation T...