Israel Medical Association Journal

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.  

Background: Device replacement or revision may constitute 25% of pacemaker procedures. In patients needing pacemaker system replacement the usual approach is from the ipsilateral side of the previous system. In cases where the contralateral side is used the previous pulse generator is removed.

Objective: To test the feasibility of implanting a new system in the contralateral side without the removal of the old system.

Methods: We present 10 patients, age range 30–88 (median 73), with clinical indication of pacemaker replacement where the contralateral side was used. In eight patients the replacement was lead-related, and in the remaining two was due to other clinical indications. In all cases the ipsilateral approach was felt to be contraindicated because of local vein and/or pocket complications. Following the new pacemaker implantation the old system was reprogrammed at the lowest rate, lowest output and highest sensitivity.

Results: All patients underwent uneventful implantation. Post-surgery monitoring and Holter recordings failed to show any interference of the old system.

Conclusions: In clinically indicated cases it is feasible to implant a new device in the contralateral side without removing the old pulse generator, thereby avoiding an additional surgical procedure and reducing periprocedural complications.

Background: The appearance of pericarditis following insertion of a permanent pacemaker is not widely acknowledged in the literature.

Objectives: To describe our experience with pericarditis following 395 permanent pacemaker implantations over 2 years.

Methods: We retrospectively reviewed the medical records of 395 consecutive patients in whom new pacing systems or pacemaker leads had been implanted over a 2 year period. We searched the records for pericarditis that developed within 1 month after pacemaker implantation according to the ICD-9 code. The incidence, clinical picture, response to treatment and relationship to lead design and location were studied.

Results: Eight cases (2%) of pericarditis following implantation were detected. Clinical manifestations in all patients were similar to those of post-pericardiotomy syndrome and included chest pain (n=7), friction rub (n=1), fever (n=2), fatigue (n=2), pleural effusion (n=2), new atrial fibrillation (n=2), elevated erythrocyte sedimentation rate (n=4) and echcardiographic evidence of pericardial effusion (n=8). All affected patients had undergone active fixation (screw-in) lead implantation in the atrial position. The incidence of pericarditis with screw-in atrial leads was 3% compared to 0% in other cases (P < 0.05).

Conclusions: Pericarditis is not uncommon following pacemaker implantation with active fixation atrial leads. Special attention should be paid to identifying pericardial complications following pacemaker implantation, especially when anticoagulant therapy is resumed or initiated. The use of passive fixation leads is likely to reduce the incidence of pericarditis but this issue should be further investigated.