Table 4.

Main publications on the safety of MRI in non-conditional pacemakers and ICDs.

Year / study	Population	Study type	Conclusions
2017 MagnaSafe11	N = 1,000 (848 pts) PM and N = 500 (428 pts) ICD cases. Inclusion criteria: non-thoracic MR scans at 1.5 T. Exclusion criteria: CIED implanted before 2002, PM-dependency, abandoned or inactive lead, thoracic MR scans.	Multicenter prospective	Device or lead failure did not occur in any patient with a non-MRI-conditional PM or ICD who underwent clinically indicated non-thoracic MRI at 1.5 T, who was appropriately screened, and who had the device reprogrammed in accordance with the prespecified protocol.
2017 Okamura et al.13	N = 442 pts with non-MRI-conditional CIEDs, 569 MR scans. Inclusion criteria: 13 scans performed with a nearly depleted battery in 9 pts. Exclusion criteria: PM-dependency.	Single center prospective	Patients with PMs and ICDs with a nearly depleted battery can safely undergo MRI when pts are not PM-dependent. In old devices, PoR or ERI during MRI may lead to oversensing and inhibition of pacing.
2017 Nazarian et al.14	N = 1,509 pts with PM (58%) or ICD (42%) non-MRI-conditional, 2,103 thoracic and non-thoracic MRI scans. Exclusion criteria: device-dependency, implanted < 4 weeks, pts with permanent surgical epicardial leads or permanent nonfunctional leads.	Single center prospective	No long-term clinically significant adverse events were reported.
2017 Padmanabhan et al.15	N = 952 pts, 80 (8.4%) underwent 97 MRI scans with CIEDs in situ with abandoned leads in place. Inclusion criteria: pts with abandoned leads.	Single center prospective	No evidence of myocardial injury as measured by paired cardiac troponin assessment. The risk of MRI with abandoned leads appears low, suggesting a favorable risk-benefit profile in pts with CIEDs and abandoned leads who are considered for MRI.
2017 Indik et al.7	HRS Expert Consensus Statement on MRI and Radiation Exposure in Pts with CIEDs		It is reasonable for pts with a non-MRI-conditional CIED system to undergo MRI if there are no fractured, epicardial, or abandoned leads, the MRI is the best test for the condition, and there is an institutional protocol and a designated responsible MR physician and CIED physician (class IIa recommendation).
2018 Lupo et al.16	N = 120 pts with conventional PM or conventional ICD, n = 142 MRI 1.5 T (55 cardiac) 1.5 T MRI non-cardiac. Exclusion criteria: device-dependency, implanted < 6 weeks, implanted before 01/01/2000.	Single center prospective	A favorable risk-benefit ratio for MRI 1.5 T in conventional PM/ICD carriers was reported at MRI, immediately after MRI, and 3–12 months after MRI.
2018 Shah et al.17	70 studies of non-MRI-conditional devices undergoing MRI were identified, allowing for analysis of 5,099 pts who underwent a total of 5,908 MRI studies (thoracic imaging in 773 pts)	Systematic review and meta-analysis	This review demonstrated low lead failure and clinical event rates in non-MRI-conditional PM and ICD recipients undergoing MRI. Observed changes were small and inter-study variance was low, suggesting that the composite event rates offer a reasonable estimate of true effect. The observed adverse events reinforce the need for ongoing vigilance and caution, particularly with older devices.
2020 Greenberg et al.8	ACR Guidance Document on MR Safe Practices: Updates and Critical Information 2019		Guidance regarding performing MRI examinations in pts with non-MRI-conditional CIEDs including PMs, ICDs, CRT pacemakers/defibrillators is deferred to current recommendations by the HRS [Indik et al.]. 7
2020 PROMeNADe18	N = 532 pts with non-MRI-conditional CIEDs, n = 608 MR scans (61 cardiac) Inclusion criteria: PM-dependency (27%), abandoned leads (2%).	Single center prospective	MRI examinations (also thoracic) can be performed safely in pts with non-MRI-conditional devices, in PM-dependent patients with ICDs, and in pts with abandoned leads. These MRI examinations can have a substantial impact on patient care, justifying the extensive resources used to perform them.
2020 Rahsepar et al.19	N = 1,464 pts with CIEDs, n = 2028 MRI examinations. Exclusion criteria: newly implanted leads, abandoned or epicardial leads, PM-dependence with an ICD without asynchronous pacing capability.	Single center prospective	There was no evidence of an association between MRI parameters that characterize patient exposure to radiofrequency energy and changes in device and lead parameters immediately after MRI.
2020 Munawar et al.20	About 35 cohort studies with a total of 5,625 pts and 7,196 MRI scans (0.5-3 T) in non-conditional CIEDs were included	Systematic review and meta-analysis	This meta-analysis affirms the safety of MRI in non-conditional CIEDs: no death or ICD shock, extremely low incidence of lead or device-related complications.
2021 Glikson et al.4	2021 ESC Guidelines on Cardiac Pacing and CRT		In pts with non-MRI-conditional PM systems, MRI should be considered if no alternative imaging mode is available and if no epicardial leads, abandoned or damaged leads, or lead adaptors/extenders are present (Class IIa). MRI may be considered in PM pts with abandoned transvenous leads if no alternative imaging modality is available (Class IIb).
2021 Bhuva et al.21	N = 970 pts with CIEDs (54% non-MRI-conditional); n = 111 (18%) scans with ‘mismatch’ devices; n = 105 (17%) scans with abandoned, epicardial or very old leads (< 2001), or scanned < 6 weeks post-implant). N = 1148 MR scans (506 (44%) cardiac). Inclusion criteria: (15%) were PM-dependent, pts with abandoned, epicardial or very old leads or scanned < 6 weeks post-implant.	Multicenter prospective	There was no increased risk of MRI in pts with non-MRI-conditional PM or ICD leads when following recommended protocols. Standardizing MR conditions for all leads would significantly improve access to MRI by enabling pts to be scanned in non-specialist centres, with no discernible incremental risk.

ACR, American College of Radiology; CIED, cardiovascular implantable electronic device; CRT, cardiac resynchronization therapy; ERI, elective replacement indicator; ESC, European Society of Cardiology; HRS, Heart Rhythm Society; ICD, implantable cardioverter-defibrillator; MR, magnetic resonance; MRI, MR imaging; PM, pacemaker; PoR, power-on resets; pts, patients.