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עמוד בית
Sun, 14.04.24

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August 2012
E. Kadmon, D. Menachemi, J. Kusniec, M. Haim, M. Geist and B. Strasberg

Background: The implantable loop recorder (ILR) is an important tool for the evaluation of unexplained syncope, particularly in cases of rarely occurring arrhythmia.

Objectives: To review the clinical experience of two Israeli medical centers with the ILR. Methods: We reviewed the medical records of patients with unexplained syncope evaluated with the ILR at Rabin Medical Center (2006–2010) and Wolfson Medical Center (2000–2009).

Results: The study group included 75 patients (44 males) followed for 11.9 ± 9.5 months after ILR implantation. Patients’ mean age was 64 ± 20 years. The ILR identified an arrhythmic mechanism of syncope in 20 patients (17 bradyarrhythmias, 3 tachyarrhythmias) and excluded arrhythmias in 12, for a diagnostic yield of 42.7%. It was not diagnostic in 17 patients (22.7%) at the time of explant 26 patients (34.7%) were still in follow-up. In two patients ILR results that were initially negative were reversed by later ILR tracings. The patients with bradyarrhythmias included 9 of 16 (56.3%) with surface electrocardiogram conduction disturbances and 2 of 12 (16.7%) with negative findings on carotid sinus massage. All bradyarrhythmic patients received pacemakers the seven patients for whom post-intervention data were available had no or mild symptoms.

Conclusions: The ILR has a high diagnostic yield. Pre-ILR findings correlating with the ILR results are conduction disturbances (positive predictor of arrhythmia) and negative carotid sinus massage results (negative predictor of arrhythmia). Proper patient instruction is necessary to obtain accurate results. Caution is advised when excluding an arrhythmia on the basis of ILR tracings, and long-term follow-up is warranted.

July 2010
O. Halshtok, O. Goitein, R. Abu Sham'a, H. Granit, M. Glikson and E. Konen
Background: Until recently, cardiac pacemakers and implantable cardioverter defibrillators were considered an absolute contraindication for magnetic resonance imaging. Given the significant increase in implanting such devices, these contraindications will preclude MRI scanning in a large patient population. Several recent reports have addressed the safety and feasibility of MRI in the presence of cardiac implantable devices.

Objectives: To summarize our experience with MRI scanning in the presence of pacemakers and implantable cardioverter defibrillators.

Methods: Eighteen patients (15 males and 3 females, median 59) were scanned using a 1.5 T MRI scanner. A clinical discussion was held to verify the absolute medical necessity of the study before performing the scan. Scan supervision included device interrogation and programming beforehand, patient monitoring during, and device interrogation and reprogramming after the scan. Full resuscitation equipment was available outside the MRI suite.

Results: Thirty-four scans were performed, and all but one were of diagnostic quality. Anatomic regions included the brain (N=26), cervical spine (N=2), lumbar spine (N=1), cardiac (N=2), abdomen (N=1), abdomen and pelvis (N=1) and pelvis (N=1). None of the patients reported any side effects and no life-threatening events occurred during or following the scans. Five cases of device spontaneous reversion to backup mode were recorded (four in the same patient). Device replacement was not required in any patient.

Conclusions: In this small cohort of patients MRI scanning in the presence of cardiac implantable devices was safe. MRI in these patients is feasible although not recommended for routine scans. Scans should be considered on a case-to-case basis and performed in a dedicated specialized setup.


February 2006
D. Goldsher, S. Amikam, M. Boulos, M. Suleiman, R. Shreiber, A. Eran, Y. Goldshmid, R. Mazbar and A. Roguin

Background: Magnetic resonance imaging is a diagnostic tool of growing importance. Since its introduction, certain medical implants, e.g., pacemakers, were considered an absolute contraindication, mainly due to the presence of ferromagnetic components and the potential for electromagnetic interference. Patients with such implants were therefore prevented from entering MRI systems and not studied by this modality. These devices are now smaller and have improved electromechanical interference protection. Recently in vitro and in vivo data showed that these devices may be scanned safely in the MRI.

Objectives: To report our initial experience with three patients with pacemakers who underwent cerebral MRI studies.

Methods: The study included patients with clear clinical indications for MRI examination and who had implanted devices shown to be safe by in vitro and in vivo animal testing. In each patient the pacemaker was programmed to pacing-off. During the scan, continuous electrocardiographic telemetry, breathing rate, pulse oximetry and symptoms were monitored. Specific absorption rate was limited to 4.0 W/kg for all sequences. Device parameters were assessed before, immediately after MRI, and 1 week later.

Results: None of the patients was pacemaker dependent. During the MRI study, no device movement was felt by the patients and no episodes of inappropriate inhibition or rapid activation of pacing were observed during the scan. At device interrogation here were no significant differences in device parameters pre-, post-, and 1 week after MRI. Image quality was unremarkable in all imaging sequences used and was not influenced by the presence of the pacemaker.

Conclusion: Given appropriate precautions, MRI can be safely performed in patients with a selected permanent pacemaker. This may have significant implications for current MRI contraindications. 

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