Magnetic Resonance Imaging–Compatible Pacemakers in Comparison with Standard Dual-Chamber Pacemakers in 36-Month Follow-up

Introduction: Due to comorbidities a substantial part of rapidly increasing population of patients with implanted pacemaker (PM) is indicated for magnetic resonance imaging (MRI) scan. The conventional MRI scan is contraindicated because of potential interaction between MRI and PM. Therefore, standard PM were technically modified to enable MRI scans. The current generation of MRI-compatible PM in combination with MRI-compatible leads allows now full-body MRI scan. The long-term performance of MRI-compatible PM in comparison to high standard PM is of substantial interest.

Methods: Thirty-five MRI-compatible PMs (Accent DR MRI; Tendril MRI leads; St. Jude Medical) were compared with 35 standard dual-chamber PMs (Accent DR; Optisense and Tendril lead; St. Jude Medical). Patient characteristics, peri-operative data (procedural time, fluoroscopy time, number of lead repositions), and standard lead parameters, as well as number of necessary system revisions were recorded. Follow-up was performed in 2 months, 1, 2 and 3 years after implantation.

Results: The demographical and clinical patient characteristics were comparable in both groups. No procedure-associated complications have been noted. Periprocedurally, standard lead parameters and the number of lead repositions were similar in both groups. Only slight differences in procedural time and in X-ray exposure time in favor of standard PM were observed. At discharge an increase in sensing of atrial MRI leads and a slight decrease in sensing of standard right ventricular leads have been observed. After 36 months all lead specific parameters nearly equalized. There were no differences in number of lead or pocket revisions between the groups.

Conclusion: The implantation of the MRI-compatible PM system is equal to standard PM in term of required operation time and intra-operative lead parameters. Moreover, system performance in 36 months follow-up is comparable to standard PM system with only minor lead-specific differences. The slightly longer mean procedural and X-ray exposure time in MRI group were most probably due to different handling of stiffer MRI leads. However, this did not result in an increase of necessary system revisions.