title: Implantable cardioverter defibrillator dysfunction during and after magnetic resonance imaging.
abstract: This report describes a patient in whom a MRI of the brain was performed without realizing that an ICD had been implanted 8 days previously. Electromagnetic noise induced during the MRI was detected as ventricular fibrillation and nearly caused inappropriate shocks. Charge time during MRI was prolonged. The battery indicator switched to "end of life," but this was reversed by capacitor reformation. These problems could have been avoided by inactivating the ICD prior to MRI. Three months later, the pacing threshold increased from 0.4 V per 0.5 ms at implantation to 2.8 V per 0.5. It is still uncertain whether radiofrequency current heating at the electrode tip caused the increased pacing threshold or if this would have occurred independently of the MRI. MRI of patients with an active ICD may cause life-threatening complications, and it is unknown if MRI may be safely performed if the ICD is inactivated. Therefore, MRI of patients with an ICD remains contraindicated.
authors.affiliation: Department of Cardiology, Rikshospitalet, University Hospital of Oslo, Norway. ole-gunnar.anfinsen@rikshospitalet.no
authors.forename: Ole-Gunnar
authors.initials: OG
authors.lastname: Anfinsen
authors.forename: Rolf Franck
authors.initials: RF
authors.lastname: Berntsen
authors.forename: Halfdan
authors.initials: H
authors.lastname: Aass
authors.forename: Erik
authors.initials: E
authors.lastname: Kongsgaard
authors.forename: Jan Peder
authors.initials: JP
authors.lastname: Amlie
mesh_terms: D001921:Brain / Q000473:pathology; D000075202:Contraindications; D017147:Defibrillators, Implantable; D004560:Electricity; D004562:Electrocardiography; D055590:Electromagnetic Phenomena; D004868:Equipment Failure; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged