Table 3

Risk stratification of performing MRI in patients with MR Unlabelled CIEDs or MR Conditional CIEDs outside specified conditions

Risk category	Scenario	Clinical risk	Level of evidence
Lowest	MR Conditional CIEDs* (meeting all conditions)	MR safety tested by device manufacturer.25–27	A
Lowest	MR Conditional CIEDs with additional MR Conditional device implanted (eg, coronary stent)	No clinical evidence of increased risk.	A
Lower	Recent implants (<6 weeks)	No clinical evidence of increased risk.49	C
	Unmet condition due to presence of additional implanted device	No clinical evidence of increased risk.	C
	Temporary surgical epicardial pacing wires (with no external component)	No clinical evidence of increased risk.66–69	C
	Unmet patient position exclusion zone, MR Conditional CIEDs	No clinical evidence of increased risk.78 79	B
	Scanning beyond SAR restrictions with MR Conditional CIEDs when required for diagnostic imaging	No clinical evidence signal of increased risk.75 76	C
	3 T MRI field strength, MR Conditional CIEDs labelled as MR Conditional at 1.5 T only	No clinical evidence of increased risk.80 81	C
	MR Unlabelled pin plug with MR Conditional generator and leads	No clinical evidence of increased risk.	C
	‘Mismatched’ CIEDs with MR Conditional generators, MR Unlabelled leads	No clinical evidence of increased risk.34	C
Intermediate	Inactive, battery-depleted CIEDs	Potential signal of increased risk from one case.34	C
	Generators implanted outside the pectoral region	Higher risk.	C
	MR Unlabelled generators, any lead MR labelling (non-pacing dependent)	Risk of device failure.	B
	MR Unlabelled generators, any lead MR labelling (pacing dependent)	Higher risk of asystole in the event of device failure.	B
	Abandoned leads (capped or not)	Lead/Tissue heating in experimental studies, no reported clinical complications.49 57 59 60 63–65	C
Higher	Stable abnormal lead parameter	Higher risk, mitigated by investigating cause and appropriate device programming.	C
	CIED component advisory warning	Higher risk depending on cause.	C
	Permanent epicardial leads	No clinical evidence of increased risk.49 67	C
	Fractured leads	Higher risk.	C
	Battery at elective replacement interval	Higher risk.	C
	Temporary systems with externalised generator	No clinical evidence of increased risk.49 71	C
	Pre-2000 market release generators	Increased risk of electrical reset.45	B
Avoid	Pacing-dependent patients with ICDs devices where not possible to maintain asynchronous pacing (VOO/DOO)	Unavoidable extremely high risk—do not scan.	C
Avoid	Scanning any active CIED without reprogramming prior to scan to minimise risk	Risk highly possible—do not scan.	C

Risk is represented as categories, but within each category the scenarios should be considered as a scale from low to progressively higher risk (top to bottom of the table - shaded from green to red respectively, with black shaded categories representing scenarios where MRI should be avoided). Overall risk is a combined consideration of the likelihood of an event and the clinical outcome if that event occurred. Scenarios considered higher risk either have a paucity of trial data describing clinical safety end points, or are based on expert consensus despite small series reporting safe MRI scanning. Level of evidence A=data derived from multiple randomised controlled trials, or meta-analyses; level of evidence B=data derived from a single randomised clinical trial or large non-randomised study; level of evidence C=consensus of expert opinion based on clinical experience or case series.
*Includes both permanent pacemakers. ICDs and implantable cardiac monitors.
CIED, cardiac implantable electronic device; ICD, implantable cardioverter-defibrillator; NA, not applicable; SAR, specific absorption rate.