Features
James Dundas is a final year Cardiology registrar, training in the North East and subspecialising in advanced cardiac imaging. He is Level 3 accredited in Cardiac MRI by the European Association of Cardiovascular Imaging, and in Transthoracic Echo by the British Society of Echocardiography.
My patient has a pacemaker and needs an MRI scan - a review of the guidance and regional survey of referring orthopaedic surgeons James Dundas, Andrew Brown, Iain Matthews, Thomas Green, Craig Runnett, David P Ripley and Honey Thomas Background
Andrew Brown is an Internal Medicine Trainee, Northumbria Healthcare NHS Foundation Trust.
Iain Matthews is a Consultant Cardiologist, Northumbria Healthcare NHS Foundation Trust.
Thomas Green is a Consultant Cardiologist, Northumbria Healthcare NHS Foundation Trust.
Craig Runnett is a Consultant Cardiologist, Northumbria Healthcare NHS Foundation Trust.
22 | JTO | Volume 10 | Issue 01 | March 2022 | boa.ac.uk
The prevalence of patients with cardiac implantable electronic devices (CIEDs) continues to increase, with approximately 57,0001 implanted in 2018/2019 in the United Kingdom. These devices include permanent pacemakers (PPM) for the treatment of bradycardia; implantable cardioverter-defibrillators (ICD) for the treatment of life-threatening ventricular arrhythmia; cardiac resynchronisation therapy (CRT) pacemakers for certain patients with severe heart failure; and lastly implantable loop recorders (ILR) used for diagnosis of intermittent arrhythmia. Some devices can perform multiple functions (e.g. CRT-defibrillators). Historically, the presence of a CIED was considered an absolute contra-indication to MRI examination due to perceived risk of device malfunction, inappropriate device therapy (including inhibition of required pacing, inappropriate pacing and inappropriate ICD shocks), and direct tissue effects such as heating. This has resulted in patients having to undergo alternative imaging modalities, which can be inferior to MRI, particularly where definition of soft tissues is required for diagnosis. More recently, the majority of CIEDs implanted are designated as MRI conditional – meaning that they have been
demonstrated to pose no known hazards, in a specified MRI environment under certain conditions (for example, magnetic field strength and the scan protocol chosen). All of the major device manufacturers market MRI conditional CIEDs, and MRI scanning for patients with these devices is robustly supported by UK and international guidelines2,3. Many centres have developed straightforward standard operating procedures (SOP) whereby the devices are reprogrammed by cardiac physiologists to MRI-safe modes before the study, and then otherwise scanned in the usual fashion. Loop recorders (ILR) and non-electronic cardiac implants (e.g. coronary stents, prosthetic heart valves) do not pose a safety risk to the patient, although it may be prudent to arrange for ILRs to be interrogated prior to scanning to acquire any useful ECG data stored. Most guidelines2,3 consider scanning redundant pacing leads (i.e. leads, or parts thereof, left behind after device upgrade or extraction) to be contraindicated, along with scanning within the first six weeks after device implant. However, experienced centres report undertaking scans in both situations 4,5. The only absolute contraindication to scanning is a ventricular assist device (VAD). Figure 1 illustrates which devices can usually be safely scanned.
