Abstract 15895: Magnetic Resonance Imaging at 1.5 Tesla in Patients with Cardiac Pacemakers: A prospective study in 388 patients
Cardiac pacemakers are still regarded as a contraindication to magnetic resonance imaging (MRI). In the following study we wanted to evaluate the feasibility and safety of cranial MRI in patients with cardiac pacemakers.
Methods: We examined 388 patients (age 64.3 ± 7.1 years, 249 men, 139 women, 143 single and 241 dual chamber systems) with cardiac pacemakers and an urgent indication for cranial MRI. 266 patients were pacemaker-dependent. Prior to the scan all pacemakers were programmed to an asynchronous stimulation mode, V00 or D00. The scans were performed with a 1.5 Tesla system (Magnetom Vision, Siemens Medical Systems, Germany). Thereby specific absorption rate was limited to 1.5 W/ kg bodyweight and total scan time was limited to 30 minutes. During the scan patients were monitored with ecg and puls oximetry. We performed follow up examinations to determine pacing capture threshold, sensing threshold, and lead impedance immediately after the scan, two weeks, and two months after the scan.
Results: MR scans could be performed safely in all patients. All patients tolerated the asynchronous stimulation. We did not register any ventricular or supraventicular arrhythmias induced by the MR scan. Programmed parameters and battery voltage remained unchanged. No pacemaker dysfunction was registered. We could not observe a significant change of pacing capture threshold (0.11 ± 0.7 ms resp.0.9 ± 0.7 V) immediately after the scan (0.11 ± 0.8 ms resp.0.9 ± 0.8 V) or in the 2 month follow up (0.11 ± 0.9 ms resp. 1.1 ± 0.8 V, p = 0.46). There was no siginificant change in sensing threshold (2.1 ± 0.9 mV vs.2.1 ± 0.8 mV atrial lead and 8.1 ± 3.8 mV vs. 8.2 ± 3.9 mV ventricular lead, p = 0.42) and lead impedance (588 ± 290 Ω vs. 599 ± 320 Ω, p = 0.55)
Conclusions: Cranial MRT with a 1.5 Tesla systems could be performed safely in patients with cardiac pacemakers. Follow up examinations did not reveal any complications, especially an increase in pacing capture threshold or a reduced sensing could not be observed.
- © 2010 by American Heart Association, Inc.