In vivo heating of pacemaker leads during magnetic resonance imaging.
OBJECTIVE
Magnetic resonance imaging (MRI) is well established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. In this study, heating effects at the myocardium-pacemaker lead tip interface have been investigated in a chronic animal model during MRI at 1.5 Tesla.


RESULTS
Pacemaker leads with additional thermocouple wires as temperature sensors were implanted in nine animals. Temperature increases of up to 20 degrees C were measured during MRI of the heart. Significant impedance and minor stimulation threshold changes could be seen. However, pathology and histology could not clearly demonstrate heat-induced damage.


CONCLUSIONS
MRI may produce considerable heating at the lead tip. Changes of pacing parameters due to MRI could be seen in chronic experiments. Potential risk of tissue damage cannot be excluded even though no reproducible alterations at the histological level could be found.
Luechinger
Roger
R
Institute of Biomedical Engineering, University and Swiss Federal Institute of Technology, Gloriastrasse 35, 8092 Zurich, Switzerland.
Zeijlemaker
Volkert A
VA
Pedersen
Erik Morre
EM
Mortensen
Peter
P
Falk
Erling
E
Duru
Firat
F
Candinas
Reto
R
Boesiger
Peter
P
D000818:Animals; D000075202:Contraindications; D017097:Electric Impedance; D006352:Heart Ventricles / Q000473:pathology; D006358:Hot Temperature / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging / Q000009:adverse effects* / Q000379:methods; D023421:Models, Animal; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D013552:Swine