TRANSESOPHAGEAL CARDIAC PACING DURING MAGNETIC-RESONANCE-IMAGING - FEASIBILITY AND SAFETY CONSIDERATIONS

The feasibility and safety of transesophageal cardiac pacing during cl inical MRI at 1.5 Tesla is considered, An MRI compatible pace catheter was developed. In vitro testing showed a normal performance of the pu lse generator, image artifacts that extended less than 11 mm from the catheter, and a less than 5% increase in noise, Cardiac stimulation in duced by MRI was not observed and, theoretically, is not expected, Pot entially, tissue around the catheter tip may become heated, This heati ng (Delta T) was monitored, Eight dogs were exposed to MRI during paci ng, For low RF radiation exposure, a time-averaged squared B-1 field b elow 0.08 pT(2) (SAR < 0.03 W/kg), Delta T was below 1 degrees C, For high RF radiation exposure, but at normal RF radiation specific absorp tion rate (0.4 W/kg), Delta T was 5 degrees C, Thus, transesophageal a trial pacing during MRI at low RF exposure seems to be possible to per form cardiac stress studies or to correct unstable heart rates.