Evaluation of Safety and Feasibility Magnetic Resonance Imaging of the Heart at 1.5 Tesla In Patients With Implantable Cardioverter Defibrillators

The presence of an implantable cardioverter defibrillators (ICD) is currently considered an absolute contraindication to MR imaging, and most patients with PM are excluded from having MRI. As a result from studies such as MADIT I, MADIT II, SCDHeft etc. the number of patients with ICDs has been continuously growing over the past years, ans this development will continue.

The aim of this study is to develop a strategy for safe performance of MR imaging at 1.5T, which included restriction of specific absorption rate (SAR) values to minimize the risk of lead heating, and ICD reprogramming to avoid interference from time varying gradient fields. The safety of this approach is then evaluated in a large group of ICD patients including assessment of potential myocardial thermal injury by measuring serum troponin I and pacing capture thresholds, and performing a follow-up 6 weeks after MR imaging to evaluate long-term effects.