Saturday, June 03, 2017

Your patient with a device needs MRI. Now what?

Here is a nice review in JACC.

Some key sections from the text:

Due to concerns of electromagnetic interference with older generators, pacemakers implanted before 1998 and ICDs implanted before 2000 are excluded. Patients with temporary leads, epicardial leads, abandoned leads, and implants within 4 weeks are also excluded and are discussed in greater detail in a separate section…

The mode of pacing is then adjusted, depending on whether or not the patient is pacemaker-dependent. In order to mitigate risk of inhibition of pacing due to detection of radiofrequency or gradient signals, pacing is set to asynchronous pacing (VOO or DOO) in pacemaker-dependent patients. To avoid inappropriate sensing of radiofrequency pulses and therefore inappropriate tracking in patients who are not pacemaker-dependent, pacing is set to a nontracking mode (VVI or DDI). For similar reasons, settings such as rate response, premature ventricular contraction response, ventricular sense response, and atrial fibrillation response are deactivated. To minimize asynchronous pacing and risk of inducing arrhythmia, magnet mode and noise reversion are deactivated. For ICDs, tachyarrhythmia monitoring is deactivated to avoid battery drainage and tachyarrhythmia therapies are deactivated to avoid antitachycardia pacing or shocks.

During the MR, electrocardiograms are recorded and blood pressure and oxygen saturation are monitored. Because no specific imaging sequences are known to increase patient risk, any imaging protocol can be performed, as needed. As discussed later, additional sequences or adjustment may be made to limit image artifacts from the device. Post examination, the original programming is restored, and lead parameters are compared to baseline values and adjusted, if necessary. A follow-up device interrogation is then performed at 3 to 6 months.

No comments: