1.A cardiologist or other qualified physician with appropriate training and experience in pacemaker/ICD function will supervise the study.
2.ACLS trained personnel and a “crash cart,” including a non-MRI compatible defibrillator and transcutaneous pacemaker, will be available throughout the procedure to respond to an adverse clinical event.
3.All patients will undergo device interrogation in the MRI suite, but outside of the magnet room, immediately prior to and following the scan.
b.Measure battery voltage, P- and R-wave amplitudes, and lead impedance and pacing threshold for all leads.
c.For ICDs, determine shock impedance only if this can be done in a painless fashion.
4.Device programming during the scan:
a.If patient has an asymptomatic intrinsic rhythm >40 bpm, program the device to no pacing (ODO or OVO).
b.For pacemaker patients, if there is no intrinsic rhythm, or symptoms are noted when the device is reprogrammed to 40 bpm, the patient is considered “dependent.” Program the device to an asynchronous pacing mode (DOO or VOO) at the previously programmed lower rate limit.
c.For ICD patients, if there is no intrinsic rhythm or symptoms are noted when the device is reprogrammed to pacing at 40 bpm, the patient is considered “dependent”, and is excluded from the study.
d.For ICDs, all tachycardia therapy functions will be disabled.
5.All patients will be monitored throughout the procedure with continuous cardiac rhythm recording and pulse oximetry. In addition, blood pressure will be obtained before, during, and after the scan.
6.Immediately following the scan, initial pacemaker parameters will be restored.
7.Post-scan interrogation: Interrogate device as for pre-scan interrogation. Perform threshold measurements at same pacing rate and pulse width amplitude as pre-scan interrogation.
a.If no significant parameter changes occur, the patient will require a single device follow-up interrogation between 3-6 months after the MRI procedure.
b.If the device had a significant parameter change, the patient will require three follow-up interrogations: