Imaging in patients with cardiovascular implantable electronic devices: part 2-imaging after device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

Cardiac implantable electronic devices (CIEDs) improve quality of life and prolong survival, but there are additional considerations for cardiovascular imaging after implantation-both for standard indications and for diagnosing and guiding management of device-related complications. This clinical consensus statement (part 2) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients after implantation of conventional pacemakers, cardioverter defibrillators, and cardiac resynchronization therapy (CRT) devices. The document summarizes the existing evidence regarding the role and optimal use of various cardiac imaging modalities in patients with suspected CIED-related complications and also discusses CRT optimization, the safety of magnetic resonance imaging in CIED carriers, and describes the role of chest radiography in assessing CIED type, position, and complications. The role of imaging before and during CIED implantation is discussed in a companion document (part 1).

The Burden of Cardiac Implantable Electronic Device Checks in the Peri-MRI Setting: The CHECK-MRI Study

BACKGROUND

Most modern cardiac implantable electronic device (CIED) systems are now compatible with magnetic resonance imaging (MRI) scans. The requirement for both pre- and post-MRI CIED checks imposes significant workload to the cardiac electrophysiology service. Here, we sought to determine the burden of CIED checks associated with MRI scans.

METHODS

We identified all CIED checks performed peri-MRI scans at our institution over a 3-year period between 1 July 2017 to 30 June 2020, comprising three separate financial years (FY). Device check reports, MRI scan reports and clinical summaries were collated. The workload burden was determined by assessing the occasions and duration of service. Analysis was performed to determine cost burden/projections for this service and identify factors contributing to the workload.

RESULTS

A total of 739 CIED checks were performed in the peri-MRI scan setting (370 pre- and 369 post-MRI scan), including 5% (n=39) that were performed outside of routine hours (weekday <8 am or >5 pm, and weekends). MRIs were performed for 295 patients (75±13 years old, 64% male) with a CIED (88% permanent pacemaker, and 12% high voltage device), including 49 who had more than one MRI scan. The proportion of total MRI scans for patients with a CIED in-situ increased each FY (from 0.5% of all MRIs in FY1, to 0.9% in FY2, to 1.0% in FY3). The weekly workload increased (R²=0.2, p<0.001), but with week-to-week variability due to ad hoc scheduling (209 days with only one MRI vs 78 days with ≥2 MRIs for CIED patients). The projected annual cost of this service will increase to AUD$161,695 in 10 years for an estimated annual 546 MRI scans for CIED patients.

CONCLUSIONS

There is an increasing workload burden and expense associated with CIED checks in the peri-MRI setting. Appropriate budgeting, staff allocation and standardisation of automated CIED pre-programming features among manufacturers are urgently needed.

Evidence to support magnetic resonance conditional labelling of all pacemaker and defibrillator leads in patients with cardiac implantable electronic devices

AIMS

Many cardiac pacemakers and defibrillators are not approved by regulators for magnetic resonance imaging (MRI). Even following generator exchange to an approved magnetic resonance (MR)-conditional model, many systems remain classified 'non-MR conditional' due to the leads. This classification makes patient access to MRI challenging, but there is no evidence of increased clinical risk. We compared the effect of MRI on non-MR conditional and MR-conditional pacemaker and defibrillator leads.

METHODS AND RESULTS

Patients undergoing clinical 1.5T MRI with pacemakers and defibrillators in three centres over 5 years were included. Magnetic resonance imaging protocols were similar for MR-conditional and non-MR conditional systems. Devices were interrogated pre- and immediately post-scan, and at follow-up, and adverse clinical events recorded. Lead parameter changes peri-scan were stratified by MR-conditional labelling. A total of 1148 MRI examinations were performed in 970 patients (54% non-MR conditional systems, 39% defibrillators, 15% pacing-dependent) with 2268 leads. There were no lead-related adverse clinical events, and no clinically significant immediate or late lead parameter changes following MRI in either MR-conditional or non-MR conditional leads. Small reductions in atrial and right ventricular sensed amplitudes and impedances were similar between groups, with no difference in the proportion of leads with parameter changes greater than pre-defined thresholds (7.1%, 95% confidence interval: 6.1-8.3).

CONCLUSIONS

There was no increased risk of MRI in patients with non-MR conditional pacemaker or defibrillator leads when following recommended protocols. Standardizing MR conditions for all leads would significantly improve access to MRI by enabling patients to be scanned in non-specialist centres, with no discernible incremental risk.

Access to MRI for patients with cardiac pacemakers and implantable cardioverter defibrillators

OBJECTIVE

To determine provision of MRI for patients with cardiac implantable electronic devices (CIEDs; pacemakers and defibrillators) in England, to understand regional variation and assess the impact of guideline changes.

METHODS

Retrospective data related to MRI scans performed in patients with CIED over the preceding 12 months was collected using a structured survey tool distributed to every National Health Service Trust MRI unit in England. Data were compared with similar data from 2014/2015 and with demand (estimated from local CIED implantation rates and regional population data by sustainability and transformation partnerships (STPs)).

RESULTS

Responses were received from 212 of 223 (95%) hospitals in England. 112 (53%) MRI units' scan patients with MR-conditional CIEDs (10% also scan non-MR conditional devices), compared with 46% of sites in 2014/2015. Total annual scan volume increased over fourfold between 2014 and 2019 (1090 to 4896 scans). There was widespread geographical variation, with five STPs (total population >3·5 million representing approximately 25 000 patients with CIED) with no local provision. There was no correlation between local demand (CIED implantation rates) and MRI provision (scan volume). Complication rates were extremely low with three events nationally in 12 months (0·06% CIED-MRI scans).

CONCLUSIONS

Provision of MRI for patients with CIEDs in England increased over fourfold in 4 years, but an estimated 10-fold care gap remains. Almost half of hospitals and 1 in 10 STPs have no service, with no relationship between local supply and demand. Availability of MRI for patients with non-MR conditional devices, although demonstrably safe, remains limited.

2020 MR Safety for Cardiac Devices: An Update for Radiologists

Magnetic resonance imaging (MRI) is a unique and powerful diagnostic tool that provides images without ionizing radiation and, at times, can be the only modality to properly assess and diagnose some pathologies. Although many patients will need an MRI in their lifetime, many of them are still being unjustly denied access to it due to what were once considered absolute contraindications, including MR nonconditional pacemakers and implantable cardioverter-defibrillators. However, there are a number of large studies that have recently demonstrated that MRI can safely be performed in these patients under certain conditions. In addition, there are an increasing number of novel cardiac devices implanted in patients who may require an MRI. Radiologists need to familiarize themselves with these devices, identify which patients with these devices can safely undergo MRI, and under which conditions. In this article, we will review the current literature on MR safety and cardiac devices, elaborate on how to safely image patients with cardiac devices, and share the expertise of our tertiary cardiac institute.

MRI safety management in patients with cardiac implantable electronic devices: Utilizing failure mode and effects analysis for risk optimization

INTRODUCTION

Cardiac implantable electronic devices (CIEDs) are increasing in prevalence. Exposing patients with CIEDs to magnetic resonance imaging (MRI) can lead to adverse outcomes. This has led certain radiology departments to not accept MRI referrals related to patients with CIEDs. Patients with MR-conditional CIEDs can be safely scanned under specific conditions. Our institution has accepted such referrals since 2014. The aim of this study was to systematically identify and reduce risk in our CIED-MRI protocol using failure mode and effects analysis (FMEA).

METHODS

A multidisciplinary FMEA team was assembled and included senior stakeholders from the CIED-MRI protocol. A process map was constructed followed by risk analysis and scoring. Targeted interventions were formulated and implemented; high-risk failure modes were prioritized. A new process map and protocol were drafted and repeat risk analysis was performed. Monitoring and re-evaluation of the CIED-MRI pathway were instigated at departmental quality assurance (QA) meetings.

RESULTS

Interventions included direct CIED characterization using wireless technology pre-MRI, CIED programming and reprogramming in the MRI suite before and immediately after MRI reducing device downtime and continuous patient monitoring during MRI by a cardiac physiologist. The cumulative risk priority number (RPN) decreased from 1190 pre-FMEA to 492 post-FMEA.

DISCUSSION

Despite the risk of exposing CIEDs to the MR environment, patients with MR-conditional CIEDs can be safely scanned with an appropriate multidisciplinary support. We found FMEA an indispensable tool in identifying and minimizing risk with no adverse events recorded since FMEA recommendations were implemented.

3.0 T magnetic resonance imaging scanning on different body regions in patients with pacemakers

PURPOSE

Magnetic resonance imaging (MRI) at 3.0 T is becoming more common, but there is a lack of sufficient evidence on the safety of a 3.0 T scan in patients with pacemakers. This study aimed to investigate the safety and practical concerns of 3.0 T scans for patients with MR-conditional pacemakers.

METHODS

Twenty consecutive patients were enrolled. A standardized protocol was developed by cardiologists, pacemaker engineers, and radiologists. Pacemaker interrogation was performed immediately before and after the scan. Scan-related adverse events were documented, and imaging quality was graded as level 1 to 4 by radiologists.

RESULTS

Twenty-three MRI scans of different body regions (brain = 13, lumbar spine = 4, cervical spine = 2, and heart = 4) were performed, and the average time of a scan was 25 ± 11 min. No significant changes in sensing amplitude (atrial 3.1 ± 1.1 mV vs. 2.9 ± 1.2 mV, P = 0.71; ventricular 9.3 ± 3.5 mV vs. 10.2 ± 3.4 mV, P = 0.46), lead impedances (atrial 647 ± 146 Ω vs. 627 ± 151 Ω, P = 0.7; ventricular: 780 ± 247 Ω vs.711 ± 226 Ω, P = 0.36), or pacing threshold (atrial 0.6 ± 0.2 V/0.4 ms vs. 0.6 ± 0.2 V/0.4 ms, P = 0.71; ventricular 0.7 ± 0.3 V/0.4 ms vs. 0.7 ± 0.2 V/0.4 ms, P = 0.85) were observed pre- and postscan. No adverse events were detected. Image quality review showed grade 1 quality in 16 patients and grade 2 quality in 4 patients with artifacts of pulse generators and leads in cardiac MRI scan and no impact on diagnostic value.

CONCLUSION

Our initial data indicated that 3.0 T scanning might be feasible under a standardized protocol with good diagnostic imaging quality irrespective of body region in patients with MR-conditional pacemakers.

Cardiac Magnetic Resonance in Patients With Cardiac Implantable Electronic Devices: Challenges and Solutions

Until recently, cardiac implantable electronic devices (CIEDs) were an absolute contraindication to magnetic resonance imaging (MRI), due to concerns about their adverse interaction in the MRI environment. The increasing clinical need to perform MRI examinations in these patients was an impetus to the development of MR-Conditional CIEDs. Secure performance of MRI in these patients requires scanning under specified MR conditions as well as operating the device in MR-scanning mode. This requires robust institutional protocols and a well-trained multidisciplinary team of radiologists, cardiologists, device applications specialists, physicists, nurses, and MRI technologists. MRI can also be performed in patients with non-MRI Conditional or "legacy" CIEDs by following safety precautions and continuous monitoring. Cardiac magnetic resonance (CMR) is additionally challenging due to expected susceptibility artifacts generated by the CIEDs, which are either near or in the heart. As the most common indication for CMR in these patients is the evaluation of myocardial scar/fibrosis, acquiring a high-quality late gadolinium enhancement image is of the utmost importance. This sequence is hampered by artifactual high signal due to inadequate myocardial nulling. Several solutions are available to reduce these artifacts, including reducing inhomogeneity, technical adjustments, and use of sequences that are more resilient to artifacts. In this article, we review the precautions for CMR in patients with CIEDs, provide guidelines for secure performance of CMR in these patients, and discuss techniques for obtaining high quality CMR images with minimized artifacts.

Cardiac MRI for Patients With Cardiac Implantable Electronic Devices

OBJECTIVE. Patients with cardiac implantable electronic devices (CIEDs) require cardiac MRI (CMRI) for a variety of reasons. The purpose of this study is to review and evaluate the value and safety of CMRI for patients with in situ CIEDs. CONCLUSION. Late gadolinium enhancement CMRI is the reference standard for assessing myocardial viability in patients with ventricular tachycardia before ablation of arrhythmogenic substrates. The use of late gadolinium enhancement CMRI for patients with CIEDs is safe as long as an imaging protocol is in place and precaution measures are taken.

An operational approach to the execution of MR examinations in patients with CIED

In the context of the increasing spread of cardiac active implantable heart devices (CIEDs) in the population and of the wide diagnostic/therapeutic utility of magnetic resonance (MRI) examinations, the goal of this paper is to provide the experience of the Santa Maria Nuova Hospital of the USL Tuscany Center in Florence and to report an organizational proposal to perform, in the hospital settings, MRI examinations on patients carrying CIED. This report is intended to show the operational choices of a Radiology Department which organizes this activity in accordance with the new Italian regulatory framework in the field of safety of MR sites (Ministero della Salute in Decreto Ministeriale 10 agosto 2018 Determinazione degli standard di sicurezza e impiego per le apparecchiature a risonanza magnetica, 2018).

Clinical and histopathological outcome of cervical and chest MRI involving non-MRI-conditional cardiac pacemakers: a study using sheep models

AIM

To examine the clinical and histopathological consequences of MRI in sheep implanted with non-MRI-conditional cardiac pacemakers.

MATERIALS AND METHODS

Under general anesthesia, active fixation leads of two dual-chamber, non-MRI-conditional cardiac pacemakers (St. Jude Medical and Medtronic) were implanted either at the right ventricular apex or at the right atrium of two male sheep and connected to the V and A channels of the pacemakers, respectively. The generators were placed in cervical subcutaneous pockets. On day 5, both sheep underwent 1.5 T cervical and chest MRI with continuous electrocardiogram monitoring. Obtained sequences were T1-weighted (T1W), T2-weighted (T2W), T2-gradient echo and diffusion weighted (DW). The employed modes were OVO, VOO and VVI for one sheep and OAO, AOO and AAI for the other (unipolar and bipolar configuration of pacing and sensing for both). Battery impedance, pacing lead impedance, intrinsic amplitude and capture thresholds were checked at baseline and after each sequence, as well as 48 h after imaging. Histopathological examination of the cardiac tissue around the lead tip was performed 4 weeks post-imaging.

RESULTS

No significant changes in device position or configuration were observed during or after MRI. Clinical outcome was uneventful in both sheep. Minor inflammatory and necrotic changes were reported after histopathological examination of the cardiac tissue around the lead tip.

CONCLUSION

1.5 T MRI of two implanted non-MRI-conditional pacemakers was found safe in terms of device configuration and stability, clinical outcome and cardiac tissue histopathological findings.

Clinical safety of ProMRI implantable cardioverter-defibrillator systems during head and lower lumbar magnetic resonance imaging at 1.5 Tesla

Magnetic resonance imaging (MRI) has long been contraindicated in patients with implanted pacemakers, defibrillators, and cardiac resynchronisation therapy (CRT) devices due to the risk of adverse effects through electromagnetic interference. Since many recipients of these devices will have a lifetime indication for an MRI scan, the implantable systems should be developed as ‘MRI-conditional’ (be safe for the MRI environment under predefined conditions). We evaluated the clinical safety of several Biotronik ProMRI (‘MRI-conditional’) defibrillator and CRT systems during head and lower lumbar MRI scans at 1.5 Tesla. The study enrolled 194 patients at 22 sites in Australia, Canada, and Europe. At ≥9 weeks after device implantation, predefined, non-diagnostic, specific absorption rate (SAR)-intensive head and lower lumbar MRI scans (total ≈30 minutes per patient) were performed in 146 patients that fulfilled pre-procedure criteria. Three primary endpoints were evaluated: freedom from serious adverse device effects (SADEs) related to MRI and defibrillator/CRT (leading to death, hospitalisation, life-threatening condition, or potentially requiring implanted system revision or replacement), pacing threshold increase, and sensing amplitude decrease, all at the 1-month post-MRI clinical visit. No MRI-related SADE occurred. Lead values remained stable, measured in clinic and monitored daily by the manufacturer home monitoring technology.

Making MRI available for patients with cardiac implantable electronic devices: growing need and barriers to change

Abstract

More than half of us will need a magnetic resonance imaging (MRI) scan in our lifetimes. MRI is an unmatched diagnostic test for an expanding range of indications including neurological and musculoskeletal disorders, cancer diagnosis, and treatment planning. Unfortunately, patients with cardiac pacemakers or defibrillators have historically been prevented from having MRI because of safety concerns. This results in delayed diagnoses, more invasive investigations, and increased cost. Major developments have addressed this—newer devices are designed to be safe in MRI machines under specific conditions, and older legacy devices can be scanned provided strict protocols are followed. This service however remains difficult to deliver sustainably worldwide: MRI provision remains grossly inadequate because patients are less likely to be referred, and face difficulties accessing services even when referred. Barriers still exist but are no longer technical. These include logistical hurdles (poor cardiology and radiology interaction at physician and technician levels), financial incentives (re-imbursement is either absent or fails to acknowledge the complexity), and education (physicians self-censor MRI requests). This article therefore highlights the recent changes in the clinical, logistical, and regulatory landscape. The aim of the article is to enable and encourage healthcare providers and local champions to build MRI services urgently for cardiac device patients, so that they may benefit from the same access to MRI as everyone else.

Key Points

• There is now considerable evidence that MRI can be provided safely to patients with cardiac implantable electronic devices (CIEDs). However, the volume of MRI scans delivered to patients with CIEDs is fifty times lower than that of the estimated need, and patients are approximately fifty times less likely to be referred.

• Because scans for this patient group are frequently for cancer diagnosis and treatment planning, MRI services need to develop rapidly, but the barriers are no longer technical.

• New services face logistical, educational, and financial hurdles which can be addressed effectively to establish a sustainable service at scale.

MRI for patients with cardiac implantable electronic devices: simplifying complexity with a 'one-stop' service model

BACKGROUND

Patients with cardiac pacemakers and defibrillators are disadvantaged because of poor access to MRI scans, leading to late and misdiagnosis particularly for cancer and neurological disease. New technology allied to tested protocols now allows safe MRI scanning of such patients; however, logistical barriers persist.

AIM

To deliver a streamlined sustainable service that provides timely MRI scans to patients with cardiac implantable electronic devices (CIEDs).

METHODS

Patients requested a 'one-stop' service for MRI, whereby devices could be reprogrammed and scans acquired at a single location and visit. To provide this 'one-stop' service, we trained a team including administrators, physicians, cardiac physiologists and radiographers. A standard protocol was used to prevent unnecessary request refusals and delays to scheduling. Service volume, waiting time and safety were analysed 6 months before and 2 years after service redesign. Waiting times for internal and external inpatient referrals plus time to treatment for patients on a cancer pathway were analysed.

RESULTS

215 MRI scans were performed over 2 years. After service redesign, MRI provision increased six-fold to 20 times the national average with reduced waiting time from 60 to 15 days and no adverse events. Departmental throughput was maintained. 85 (40%) referrals were external. 41 (19%) inpatients were scanned, reducing bed-stay by 3 days for internal referrals. 24 (11%) scans were for suspected cancer, 83% allowed treatment within the national standard of 62 days. There was no preintervention service for either inpatients or suspected cancer investigation.

CONCLUSION

Implementation of a 'one-stop' service model to provide MRI for patients with CIEDs is safe, streamlined, scalable and has reduced delays making economic and clinical sense. Protocols and checklists are available at mrimypacemaker.com.

Cardiovascular magnetic resonance imaging in patients with cardiac implantable electronic devices: best practice and real-world experience

Aims

Cardiovascular magnetic resonance (CMR) imaging has long been a contraindication for patients with a cardiac implantable electronic device (CIED). Recent studies support the feasibility and safety for non-thoracic magnetic resonance imaging, but data for CMR are sparse. The aim of the current study was to determine the safety in patients with magnetic resonance (MR)-conditional or non-MR-conditional CIED and to develop a best practice approach.

Methods and results

All patients with a CIED undergoing CMR imaging (1.5 T) between April 2014 and April 2017 were included in the study. Devices were programmed according to the standardized protocol directly before and after the CMR examination. Follow-up interrogation was performed 6 months after CMR examination. Results were compared with a large, reference cohort of CIED patients not undergoing any MR examination. A total of 200 consecutive patients with a CIED (non-MR-conditional, n = 103) were included in the study. Directly after CMR imaging, one device failure (0.5%, battery status = end of service) was noted necessitating premature generator replacement. In three patients (2%) of pacemaker/implantable cardioverter-defibrillator (ICD) carriers a sustained ventricular tachycardia (VT) occurred during CMR imaging. Ten ICD showed a decrease in battery capacity immediately after CMR. Overall, the reference cohort showed comparable changes of CIED function during follow-up.

Conclusion

With adherence to a standardized protocol and established exclusion criteria CMR imaging could safely be performed in patients with a CIED. The potential risks of device malfunction necessitate the presence of a device trained individual during the entire CMR examination. If there is a history of VT storm the attendance of an experienced cardiologist, should be mandatory.

Magnetic resonance imaging in patients with cardiac implantable electronic devices

In recent years the prevalence of implantation of a cardiac implantable electronic device (CIED) has increased due to expanding implantation indications and prolonged life expectancy. Diagnostic strategies increasingly employ magnetic resonance imaging (MRI) to aid therapeutic strategies. In earlier guidelines, MRI was contra-indicated in patients with CIEDs, mainly due to previous reports of severe complications. With the development of MRI-conditional CIEDs and recent evidence concerning non-MRI-conditional CIEDs, MRIs in CIED patients can be safely performed in many hospitals.However, there are several questions that need to be addressed. Which patients can we scan? How can the scans be performed safely? And last but not least, can cardiac MRI provide diagnostic yield in patients with CIEDs?Current European guidelines are rather outdated and vague about patient selection and practical issues. There are national guidelines on this topic but several issues need extra attention and those are addressed in this point of view. It is important to create an environment with proper patient selection without unnecessary MRI scans in CIED patients, but also without unnecessary fear of complications, preventing access to MRI in patients who can benefit from this powerful diagnostic tool.

Provision of MR imaging for patients with cardiac implantable electronic devices (CIEDs): a single-center experience and national survey

BACKGROUND

Patients with cardiac implantable electronic devices (CIEDs) were traditionally denied access to MR imaging due to safety concerns.

AIMS

The aim of this study was to review a single-center experience of MR imaging at 1.5T of patients with CIEDs and survey national availability of this service.

METHODS

Three hundred thirty-four patients with CIEDs were included in the review. Two hundred nine patients did not progress to MRI due to non MR-conditional CIEDs, retained pacing leads, recent implant insertion, and other patient factors. A record was made of CIED type, number of body parts imaged, numbers of repeat studies and complications. All devices were scanned with cardiology involvement.

RESULTS

One hundred twenty-five patients, 90 males, 35 females, aged 20-91 years progressed to MR imaging. Eighty-six patients had pacemakers, 15 had implantable cardioverter devices (ICDs), and 24 had implantable loop recorders (ILRs). Twenty-one patients had more than one body part scanned. Regions scanned included spine n = 82, joints n = 42, head n = 40, heart n = 8, and abdomen/pelvis n = 13. Twenty-six patients had multiple separate MR studies (range 2-6). Three complications included diaphragmatic stimulation when the device was switched to MR-conditional mode resulting in scan abandonment, device failure post-MRI requiring manufacturer reprogramming, and patient dizziness post reprogramming requiring cardiology review. One cardiac study was non-diagnostic due to artifact from a low left-sided ICD. Imaging of patients with pacemakers is available in 14 of 42 (38%) hospitals with MR units nationally.

CONCLUSION

MR-conditional CIEDs can be safely scanned with diagnostic quality at 1.5T using a protocol involving radiology and cardiology.