The Effects of Nuclear Magnetic Resonance on Patients with Cardiac Pacemakers

Abstract

The effect of nuclear magnetic resonance (NMR) imaging on eight representative cardiac pacemakers was studied. The results indicate that the threshold for initiating the asynchronous mode of a pacemaker is 11 gauss, although the pacemaker is not damaged by NMR imaging. When the demand type pacemaker is programmed to magnet response “OFF” under the gradient magnetic field and radiofrequency, pacing pulse of the unit is suppressed or is turned to fixed rate mode by sensing circuit discrimination. Therefor it should be better for us to refrain from giving NMR imaging to a patient with a pacemaker.