Clinical safety of an MRI conditional implantable cardioverter defibrillator system: A prospective Monocenter ICD-Magnetic resonance Imaging feasibility study (MIMI).
BACKGROUND
The aim of this study was to evaluate the safety and efficacy of the Lumax 740(®) Implantable Cardioverter Defibrillator (ICD) system in patients undergoing a defined 1.5 Tesla (T) MRI.


METHODS
Between November 2013 and April 2014, eighteen patients (age range, 41-78 years; mean age, 64 years) implanted with a Lumax 740(®) ICD system for at least 6 weeks before an MRI were enrolled into this single-center feasibility study. The local ethics committee approved the study before patients gave written informed consent. Patients underwent defined MRI 1.5T of the brain and lower lumbar spine with three safety follow-up evaluations obtained during the 3-month study period. Data were analyzed descriptively. Study endpoints were the absence of either MRI and pacing system related serious adverse device effects (SADE), or of a ventricular pacing threshold increase >0.5V, or of an R-wave amplitude attenuation < 50%, or of an R-wave amplitude < 5.0 mV at 1-month follow-up. The assessment of safety and efficacy was supported by recording of all adverse events, changes in pacing threshold, R-wave sensing, pacing impedances and in battery status.


RESULTS
Sixteen patients completed the MRI and the follow-up period. As no SADE occurred, the SADE free rate was 100%. Freedom from ventricular pacing threshold increase was 100% (16/16; 95%CI: 82.9%; 100.0%). There were no significant differences between baseline and follow-up measurements of sensing amplitudes (-0.58 ± 2.07 mV, P = 0.239, -0.41 ± 1.04 mV, P = 0.133, and -0.25 ± 1.36 mV, P = 0.724, for immediately after, 1 month and 3 months after MRI scan, respectively) and pacing thresholds (-0.047 ± 0.18 V, P = 0.317, -0.019 ± 0.11 V, P = 0.490, and 0.075 ± 0.19 V, P = 0.070, for immediately after, 1 month and 3 months after MRI scan, respectively). Lead impedances after the MRI scan were significantly lower as compared with baseline values (-22.8 ± 21.69 Ω, P = 0.001, -21.62 ± 39.71 Ω, P = 0.040, and -33.68 ± 57.73 Ω, P = 0.018, for immediately after, 1 month and 3 months after MRI scan, respectively).


CONCLUSIONS
MRI scans in patients with MRI conditional ICD system (Lumax 740(®) ) are feasible and can be performed safely under defined conditions in a hospital setting.
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Alexander
A
Kypta
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Hermann
H
Blessberger
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Simon
S
Hoenig
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Karim
K
Saleh
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Thomas
T
Lambert
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Juergen
J
Kammler
Department of Radiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Franz
F
Fellner
Department of Cardiology, Clinic of Internal Medicine II, Paracelsus Medical University of Salzburg, Salzburg, Austria.
Michael
M
Lichtenauer
Department of Cardiology, Linz General Hospital, Johannes Kepler University School of Medicine, Linz, Austria.
Clemens
C
Steinwender
D000328:Adult; D000368:Aged; D000465:Algorithms; D017147:Defibrillators, Implantable; D004868:Equipment Failure; D004869:Equipment Safety; D005240:Feasibility Studies; D005260:Female; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D061214:Patient Safety; D011446:Prospective Studies; D015203:Reproducibility of Results
adverse events; implantable cardioverter defibrillator; magnetic resonance imaging; safety