In-vitro mapping of E-fields induced near pacemaker leads by simulated MR gradient fields

This article explores the problem of using an MRI machine on a patient with a cardiac pacemaker. Usually, in practice, MRI scanning of patients with cardiac pacemakers is avoided because the time varying magnetic field produced by the MRI machine may disrupt the pacemaker. First, the researchers mapped the magnetically induced electric field near the tips of wire leads in a saline tank (saline-to mimic the body's environment). The goal of the experiments was to determine the induced electric field and compare it to the actual electric field used in the pacemaker; to see if the MRI machine could, in-fact, cause pacing disruptions.

The researchers performed the experiment scaled down with a time varying magnetic field of 1 Tesla per second with a sinusoidal waveform of 1kHz. The researchers then scaled up their results to 30 Teslas/second and found that the induced electric field was actually greater than the electric field used in the device. They concluded that MRI scanning could potentially cause drastically altered paces depending on the situation and the pacemaker.

I found this interesting because this article highlights yet another problem with fully mechanical artificial hearts using electronics (relevant to our current device design project). My device design group is using magnetically powered motors in our artificial heart. MRI scanning could cause problems with the motor and delicate sensors in our device. This would make it harder to examine a patient with our device, adding to the long list of complications to having an artificial heart, this would be unfortunate.

Here's the link:

http://www.biomedical-engineering-online.com/content/8/1/39

Michael Serafino

VTPP 435-502