Safety of Patients with Conventional Pacemaker System
and MRI-Conditional Pacemaker System Undergo Magnetic
Resonance Imaging [MRI] at Ramathibodi Hospital
Alisara Anannab MD1, Tachapong Ngarmukos MD2, Sirin Apiyasawat MD2
Affiliation :
1 Cardiovascular and Intervention Unit, Central Chest Institute of Thailand, Nonthaburi, Thailand
2 Division of Cardiology, Department of Internal Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Background : MRI-conditional pacemaker system has been safely used in clinical practice worldwide. However, there are many
patients with conventional pacemaker system need magnetic resonance imaging [MRI] evaluation with strong clinical indication
that bene(cid:976)it of MRI outweighs the risks.
Objective : To investigate the safety of conventional pacemaker system and MRI-conditional pacemaker system in MRI scanning
in term of the adverse occurrence such as a) a signi(cid:976)icant change in pacing capture threshold [PCT] of any leads, b) abnormal
pacemaker function, and c) major adverse clinical event.
Materials and Methods : A retrospective study of consecutive pacemaker patients that underwent MRI at 1.5 Tesla and estimated
speci(cid:976)ic absorption rate [SAR] of less than 2.0 W/kg, under institution safety protocol, between August 2012 and June 2014, was done.
Results : Sixteen patients (mean age 77.6 years old, 50% male) with a total of 32 leads and 16 pulse generators underwent MRI
between August 2012 and June 2014 were included. Of all patients, eight (50%) were MRI-conditional pacemaker system, and (cid:976)ive
(31%) were pacemaker-dependent. The majority of MRI scanning position was brain (8, 50%), followed by spine (6, 37.5%) and
others (2, 12.5%), which included upper abdomen and lower limb. Unintended cardiac stimulation induced by magnet occurred
in one patient with conventional pacemaker system without signi(cid:976)icant clinical consequences. There was no other MRI-related
complication during and after the scan. At six months follow-up, 12 patients had their pacemaker evaluated. There was no occurrence
of signi(cid:976)icant change in PCT or abnormal pacemaker function found at six months follow-up.
Conclusion : Patients with conventional pacemaker system who have strong clinical indication for MRI may safely undergo the scan
with close and continuous monitoring strategy.
Keywords : Permanent pacemaker and MRI, Safety of pacemaker patients and MRI
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