How much heating is associated with magnetic resonance imaging in patients with pacemakers and implantable cardioverter defibrillators

Methods Methods: We tested the effect of MRI on local tissue heating over PM/ICD pulse generators (PGs) in a consecutive series of 34 non-thoracic scans in 30 patients (pts) enrolled in an ongoing registry study. MRI was performed with a General Electric 1.5 tesla model Signa HDXT scanner. Temperatures were taken immediately preand post-study with an infrared thermometer beamed at the center of the PG pocket and symmetrically on the opposite side of the anterior chest. Ambient temperature was set at 66°F. Pacing modes during MRI were 0D0 for intrinsic rates > 40 and D00 for rates < 40. Diffusion scan sequences were excluded in PM dependent pts. Devices were St. Jude (n = 11), Boston Scientific (n = 12) or Medtronic (n = 11). The primary endpoint was change in device-side versus control-side skin temperature.