Safety of Magnetic Resonance Imaging in Patients with Cardiac Devices

Magnetic Resonance Myocardial Imaging in Patients With Implantable Cardiac Devices: Challenges, Techniques, and Clinical Applications

Cardiovascular magnetic resonance imaging (MRI) in patients with cardiac implants, such as pacemakers and defibrillators, has gained importance in recent years with the development of modern cardiac implantable electronic devices. The increasing clinical need to perform MRI examinations in patients with cardiac implants has driven the development of new advanced MRI sequences to mitigate image artifacts associated with cardiac implants. More specifically, advances in imaging techniques, such as wideband late gadolinium enhancement imaging, wideband T1 mapping, and wideband perfusion, have been designed to improve image quality and examinations in patients with cardiac implants, enabling a comprehensive and more reliable diagnosis, which was previously unattainable in these patients. This review article explores recent developments and applications of wideband techniques in the field of cardiovascular MRI, offering insights into their transformative potential. Clinical applications of wideband cardiovascular MRI are highlighted, particularly in assessing myocardial viability, guiding ventricular tachycardia ablation, and characterizing myocardial tissue.

Imaging to Facilitate Ventricular Tachycardia Ablation: Intracardiac Echocardiography, Computed Tomography, Magnetic Resonance, and Positron Emission Tomography

Catheter ablation is a well-established and effective strategy for the management of ventricular tachycardia (VT). However, the identification and characterization of arrhythmogenic substrates for targeted ablation remain challenging. Electrogram abnormalities and responses to pacing during VT provide the classical and most validated methods to identify substrates. However, the 3-dimensional nature of the myocardium, nonconductive tissue, and heterogeneous strands of conductive tissue at the border zones or through the nonconductive zones can prohibit easy electrical sampling and identification of the tissue critical to VT. Intracardiac echocardiography is critical for identification of anatomy, examination of catheter approach and contact, assessment of tissue changes during ablation, and even potential substrates as echogenic regions, but lacks specificity with regard to the latter compared with advanced modalities. In recent decades, cardiac magnetic resonance, computed tomography and positron emission tomography have emerged as valuable tools in the periprocedural evaluation of VT ablation. Cardiac magnetic resonance has unparalleled soft tissue and temporal resolution and excels at identification of expanded interstitial space caused by myocardial infarction, fibrosis, inflammation, or infiltrative myopathies. Computed tomography has excellent spatial resolution and is optimal for identification of anatomic variabilities including wall thickness, thrombus, and lipomatous metaplasia. Positron emission tomography excels at identification of substrates including amyloidosis, sarcoidosis, and other inflammatory substrates. These imaging modalities are vital for assessing arrhythmogenic substrates, guiding optimal access strategy, and assessing ablation efficacy. Although clearly beneficial in specific settings, further clinical trials are needed to enhance generalizability and optimize integration of cardiac imaging for VT ablation.

Prognostic Implications of Left Ventricular Hypertrophy and Mechanical Function in Fabry Disease: A Longitudinal Cohort Study

BACKGROUND

The prognostic value of different grades of left ventricular hypertrophy (LVH) and left ventricular (LV) mechanical function in Fabry disease is unclear. We aimed to evaluate the association between the severity of LVH, LV mechanical function, and clinical outcomes in Fabry disease.

METHODS

We conducted a retrospective cohort study from a single-center registry of adult patients with Fabry disease. Left ventricular mass index (LVMI) was measured by echocardiography. The severity of LVH was categorized by LVMI using the sex-specific cutoff values. Left ventricular mechanical function was measured as LV global longitudinal strain (GLS) by speckle-tracking analysis. The primary outcome was a composite of major adverse cardiovascular events (MACE) at 5 years, including heart failure hospitalization, sustained ventricular tachycardia, acute ischemic stroke, and all-cause mortality.

RESULTS

The study included 268 patients (age 50.4 ± 15.4 years, men 46.6%) with Fabry disease (83.2% IVS4+919G > A mutation), and 106 patients (39.6%) had LVH. Patients with mild, moderate, or severe LVH had 5-year MACE rates of 7.4%, 10%, and 30.5%, respectively (P < .001). Moreover, patients with impaired LV GLS (<14.1%) had a higher 5-year MACE rate than those with preserved LV GLS (32.1% vs 2.4%, P < .001). Severe LVH was an independent predictor of MACE compared with absence of LVH (adjusted hazard ratio, 12.73; 95% CI, 1.3-124.71; P = .03), after adjusting for age, sex, hypertension, hyperlipidemia, atrial fibrillation, renal function, average E/e', enzyme replacement therapy, and LV GLS. Patients with severe LVH and impaired LV GLS had the highest incidence for MACE (log-rank P < .05), irrespective of sex, genotypes, and whether receiving enzyme replacement therapy or not.

CONCLUSIONS

Sex-specific grading of LVH by LVMI is practical for risk stratification in patients with Fabry disease, and impaired LV GLS further refines the prognostication.

Assessment of Tricuspid Regurgitation by Cardiac Magnetic Resonance Imaging: Current Role and Future Applications

Tricuspid regurgitation (TR) is a prevalent valvular disease with a significant mortality rate. The evaluation of TR severity and associated right heart remodeling and dysfunction is crucial to determine the optimal therapeutic strategy and to improve prognosis. While echocardiography remains the first-line imaging technique to evaluate TR, it has many limitations, both operator- and patient-related. Cardiovascular magnetic resonance imaging (CMR) has emerged as an innovative and comprehensive non-invasive cardiac imaging technique with additional value beyond routine echocardiographic assessment. Besides its established role as the gold standard for the evaluation of cardiac volumes, CMR can add important insights with regard to valvular anatomy and function. Accurate quantification of TR severity, including calculation of regurgitant volume and fraction, can be performed using either the well-known indirect volumetric method or novel 4D flow imaging. In addition, CMR can be used to assess the impact on the right heart, including right heart remodeling, function and tissue characterization. Several CMR-derived parameters have been associated with outcome, highlighting the importance of multi-modality imaging in patients with TR. The aim of this review is to provide an overview of the current role of CMR in the assessment and management of patients with TR and its future applications.

How to use chest radiographs and ECGs in children with pacemakers

A child with pacemaker is an uncommon presentation to the general paediatric ward, and most clinicians without previous experience may not feel confident in assessing these patients. This article provides an overview of paediatric pacemakers and commonly found radiological and electrophysiological correlates along with clinical consideration.

Recommendations for cardiovascular magnetic resonance and computed tomography in congenital heart disease: a consensus paper from the CMR/CCT Working Group of the Italian Society of Pediatric Cardiology and the Italian College of Cardiac Radiology endorsed by the Italian Society of Medical and Interventional Radiology (Part II)

Cardiovascular magnetic resonance (CMR) and computed tomography (CCT) are advanced imaging modalities that recently revolutionized the conventional diagnostic approach to congenital heart diseases (CHD), supporting echocardiography and often replacing cardiac catheterization. This is the second of two complementary documents, endorsed by experts from the Working Group of the Italian Society of Pediatric Cardiology and the Italian College of Cardiac Radiology of the Italian Society of Medical and Interventional Radiology, aimed at giving updated indications on the appropriate use of CMR and CCT in different clinical CHD settings, in both pediatrics and adults. In this article, support is also given to radiologists, pediatricians, cardiologists, and cardiac surgeons for indications and appropriateness criteria for CMR and CCT in the most referred CHD, following the proposed new criteria presented and discussed in the first document. This second document also examines the impact of devices and prostheses for CMR and CCT in CHD and additionally presents some indications for CMR and CCT exams when sedation or narcosis is needed.

Safety of magnetic resonance imaging in patients with cardiac implantable electronic devices and abandoned or epicardial leads: a systematic review and meta-analysis

AIMS

Persistent reluctance to perform magnetic resonance imaging (MRI) in patients with abandoned and/or epicardial leads of cardiac implantable electronic devices is related to in vitro studies reporting tip heating. While there is a plethora of data on the safety of MRI in conditional and non-conditional implantable devices, there is a clear lack of safety data in patients with abandoned and/or epicardial leads.

METHODS AND RESULTS

Relevant literature was identified in Medline and CINAHL using the key terms 'magnetic resonance imaging' AND 'abandoned leads' OR 'epicardial leads'. Secondary literature and cross-references were supplemented. For reporting guidance, the Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 was used. International Prospective Register of Systematic Reviews (PROSPERO) registration number 465530. Twenty-one publications with a total of 656 patients with 854 abandoned and/or epicardial leads and 929 MRI scans of different anatomical regions were included. No scan-related major adverse cardiac event was documented, although the possibility of under-reporting of critical events in the literature should be considered. Furthermore, no severe device dysfunction or severe arrhythmia was reported. Mainly transient lead parameter changes were observed in 2.8% in the subgroup of patients with functional epicardial leads. As a possible correlate of myocardial affection, subjective sensations occurred mainly in the subgroup with abandoned epicardial leads (4.0%), but no change in myocardial biomarkers was observed.

CONCLUSION

Existing publications did not report any relevant adverse events for MRI in patients with abandoned and/or epicardial leads if performed according to strict safety guidelines. However, a more rigorous risk-benefit calculation should be made for patients with epicardial leads.

Pre- and post-procedural cardiac imaging (computed tomography and magnetic resonance imaging) in electrophysiology: a clinical consensus statement of the European Heart Rhythm Association and European Association of Cardiovascular Imaging of the European Society of Cardiology

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging-specifically MR-may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

A Deep Learning Approach to Classify Fabry Cardiomyopathy from Hypertrophic Cardiomyopathy Using Cine Imaging on Cardiac Magnetic Resonance

A challenge in accurately identifying and classifying left ventricular hypertrophy (LVH) is distinguishing it from hypertrophic cardiomyopathy (HCM) and Fabry disease. The reliance on imaging techniques often requires the expertise of multiple specialists, including cardiologists, radiologists, and geneticists. This variability in the interpretation and classification of LVH leads to inconsistent diagnoses. LVH, HCM, and Fabry cardiomyopathy can be differentiated using T1 mapping on cardiac magnetic resonance imaging (MRI). However, differentiation between HCM and Fabry cardiomyopathy using echocardiography or MRI cine images is challenging for cardiologists. Our proposed system named the MRI short-axis view left ventricular hypertrophy classifier (MSLVHC) is a high-accuracy standardized imaging classification model developed using AI and trained on MRI short-axis (SAX) view cine images to distinguish between HCM and Fabry disease. The model achieved impressive performance, with an F1-score of 0.846, an accuracy of 0.909, and an AUC of 0.914 when tested on the Taipei Veterans General Hospital (TVGH) dataset. Additionally, a single-blinding study and external testing using data from the Taichung Veterans General Hospital (TCVGH) demonstrated the reliability and effectiveness of the model, achieving an F1-score of 0.727, an accuracy of 0.806, and an AUC of 0.918, demonstrating the model's reliability and usefulness. This AI model holds promise as a valuable tool for assisting specialists in diagnosing LVH diseases.

MRI in Adult Patients with Active and Inactive Implanted MR-conditional, MR-nonconditional, and Other Devices

Active implanted medical devices (AIMDs) enable therapy and patient monitoring by way of electrical activity and typically have a battery and electrical leads. The most common types of AIMDs include cardiac implantable electronic devices (CIEDs), spinal cord stimulators, deep brain stimulators, bone growth or fusion stimulators, other neurostimulators, and drug infusion pumps. As more patients with AIMDs undergo MRI, it is important to consider the safety of patients who have these implanted devices during MRI. The authors review the physics concepts related to MRI safety, such as peak spatial gradient magnetic field, specific absorption rate, root mean square value of the effective magnetic component of the transmitted RF pulse, and gradient slew rate, as well as the parameters necessary to remain within safety limits. The roles of MRI safety personnel, as set forth by the International Society of Magnetic Resonance in Medicine, are emphasized. In addition, the relevant information provided in vendor manuals is reviewed, with a focus on how to obtain relevant up-to-date information. The radiologist should be able to modify protocols to meet safety requirements, address possible alternatives to MRI, and weigh the potential benefits of MRI against the potential risks. A few more advanced topics, such as fractured or abandoned device leads and patients with multiple implanted medical devices, also are addressed. Recommended workflows for MRI in patients with implanted medical devices are outlined. It is important to implement an algorithmic MRI safety process, including a review of the MRI safety information; patient screening; optimal imaging; and monitoring patients before, during, and after the examination. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Shetty et al in this issue.

Access to MRI in Patients With Cardiac Implantable Electronic Devices is Variable and an Issue in Australia

AIMS

This study aimed to characterise the level of access to magnetic resonance imaging (MRI) in Australian hospitals for patients with MR-conditional and non-MR-conditional cardiac implantable electronic devices (CIED), and to identify any barriers impeding this access.

METHODS

All Australian Tertiary Referral Public Hospitals (n=38) were surveyed with a mixed qualitative and quantitative questionnaire. Provision of MRI to patients with MR-conditional and non-MR-conditional CIEDs; patient monitoring strategies during scan and personnel in attendance; barriers impeding MRI access.

RESULTS

Of the 35 (92%) hospitals that completed the survey, a majority (85.7%) scan MR-conditional CIEDs, while a minority (8.6%) scan non-MR-conditional CIEDs. MR-conditional device scanning is often limited to non-pacing dependent patients, excluding implantable cardioverter-defibrillators. In total, 21% of sites exclude thoracic MR scans for CIED patients. Although most centres scan on 1.5 Tesla (T) machines (59%), 10% scan at 3T and 31% scan at both strengths. Sites vary in patient monitoring strategies and personnel in attendance; 80% require staff with Advanced Cardiac Life Support to be present. Barriers to service expansion include an absence of national guidelines, formal training, and logistical device support.

CONCLUSIONS

Most surveyed Australian hospitals offer MRI for patients with MR-conditional CIEDs, however many still have exclusions for particular patient groups or scan requests. Only three surveyed sites offer MRI for patients with non-MR-conditional CIEDs in Australia. A national effort is needed to address the identified barriers including the development of national guidelines, formal training, and logistical support.

Trends in magnetic resonance and computed tomography angiography utilization among Medicare beneficiaries between 2013 and 2020

PURPOSE

To evaluate relative and absolute utilization trends and practice patterns in the United States for MRA and CTA.

METHODS

Using Medicare Part B physician payment databases (2013-2020), MRA and CTA interpreting physicians and exams were identified using the unique MRA and CTA Healthcare Common Procedure Coding System codes. The number of exams, physicians, demographics, use of contrast, and payments were summarized annually and analyzed to evaluate trends before and during the first year of the COVID-19 pandemic.

RESULTS

From 2013 to 2019, the annual number of MRA exams performed decreased by 17.9 %, while the number of CTA exams increased by 90.3 %. The number of physicians interpreting MRA decreased in both hospital (-17.2 %) and outpatient (-7.5 %) environments. The number of physicians interpreting CTA increased in both hospital (+29.4 %) and outpatient (+54.3 %) environments. During the first year of the COVID-19 pandemic, MRA utilization decreased across all imaging environments by 25.0 % whereas CTA only decreased by 5.5 %. Intracranial MRA studies were most often performed without contrast, while contrast use for neck MRA was performed at similar rates as non-contrast exams.

CONCLUSION

The overall utilization of MRA and the number of interpreting physicians are decreasing. On the other hand, CTA use and its number of interpreting physicians are increasing. During the first year of the COVID-19 pandemic, use of both MRA and CTA decreased, but the utilization of MRA decreased at five times the rate of CTA.

Impact of MRI RF coil design on the RF-induced heating of medical implants: fixedB1+rmsexposure versus normal operating mode

A direct comparison of the impact of RF coil design under specific absorption rate andB1+rmslimitations are investigated and quantified using RF coils of different geometries and topologies at 64 MHz and 128 MHz. The RF-inducedin vivoelectric field and power deposition of a 50 cm long pacemaker and 55 cm long deep brain stimulator (DBS) are evaluated within two anatomical models exposed with these RF coils. The associated uncertainty is quantified and analyzed under a fixedB1+rmsincident and normal operating mode. For a fixedB1+rmsincident, thein vivoincident field shows a much higher uncertainty (>5.6 dB) to the RF coil diameter compared to other design parameters (e.g. <2.2 dB for coil length and topology), while the associated uncertainty reduced greatly (e.g. <1.5 dB) under normal operating mode exposure. Similar uncertainties are observed in the power deposition near the pacemaker and DBS electrode. Compared to the normal operating mode, applying a fixedB1+rmsfield to the untested implant will lead to a large variation in the induced incident and power deposition of the implant, as a result, a larger safe margin when different coil designs (e.g. coil diameter) are considered.

Balanced-force shim system for correcting magnetic-field inhomogeneities in the heart due to implanted cardioverter defibrillators

Background

In the US, 1.4 million people have implanted ICDs for reducing the risk of sudden death due to ventricular arrhythmias. Cardiac MRI (cMR) is of particular interest in the ICD patient population as cMR is the optimal imaging modality for distinguishing cardiac conditions that predispose to sudden death, and it is the best method to plan and guide therapy. However, all ICDs contain a ferromagnetic transformer which imposes a large inhomogeneous magnetic field in sections of the heart, creating large image voids that can mask important pathology. A shim system was devised to resolve these ICD issues. A shim coil system (CSS) that corrects ICD artifacts over a user-selected Region-of-Interest (ROI), was constructed and validated.

Methods

A shim coil was constructed that can project a large magnetic field for distances of ~15 cm. The shim-coil can be positioned safely anywhere within the scanner bore. The CSS includes a cantilevered beam to hold the shim coil. Remotely controlled MR-conditional motors allow 2 mm-accuracy three-dimensional shim-coil position. The shim coil is located above the subjects and the imaging surface-coils. Interaction of the shim coil with the scanner's gradients was eliminated with an amplifier that is in a constant current mode. Coupling with the scanners' radio-frequency (rf) coils, was reduced with shielding, low-pass filters, and cable shield traps. Software, which utilizes magnetic field (B0) mapping of the ICD inhomogeneity, computes the optimal location for the shim coil and its corrective current. ECG gated single- and multiple-cardiac-phase 2D GRE and SSFP sequences, as well as 3D ECG-gated respiratory-navigated IR-GRE (LGE) sequences were tested in phantoms and N = 3 swine with overlaid ICDs.

Results

With all cMR sequences, the system reduced artifacts from >100 ppm to <25 ppm inhomogeneity, which permitted imaging of the entire left ventricle in swine with ICD-related voids. Continuously acquired Gradient recalled echo or Steady State Free Precession images were used to interactively adjust the shim current and coil location.

Conclusion

The shim system reduced large field inhomogeneities due to implanted ICDs and corrected most ICD-related image distortions. Externally-controlled motorized translation of the shim coil simplified its utilization, supporting an efficient cardiac MRI workflow.

Cardiac MRI at Low Field Strengths

Cardiac MR imaging is well established for assessment of cardiovascular structure and function, myocardial scar, quantitative flow, parametric mapping, and myocardial perfusion. Despite the clear evidence supporting the use of cardiac MRI for a wide range of indications, it is underutilized clinically. Recent developments in low-field MRI technology, including modern data acquisition and image reconstruction methods, are enabling high-quality low-field imaging that may improve the cost-benefit ratio for cardiac MRI. Studies to-date confirm that low-field MRI offers high measurement concordance and consistent interpretation with clinical imaging for several routine sequences. Moreover, low-field MRI may enable specific new clinical opportunities for cardiac imaging such as imaging near metal implants, MRI-guided interventions, combined cardiopulmonary assessment, and imaging of patients with severe obesity. In this review, we discuss the recent progress in low-field cardiac MRI with a focus on technical developments and early clinical validation studies. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 1.

Joint British Society consensus recommendations for magnetic resonance imaging for patients with cardiac implantable electronic devices

Magnetic Resonance Imaging (MRI) is increasingly a fundamental component of the diagnostic pathway across a range of conditions. Historically, the presence of a cardiac implantable electronic device (CIED) has been a contraindication for MRI, however, development of MR Conditional devices that can be scanned under strict protocols has facilitated the provision of MRI for patients. Additionally, there is growing safety data to support MR scanning in patients with CIEDs that do not have MR safety labelling or with MR Conditional CIEDs where certain conditions are not met, where the clinical justification is robust. This means that almost all patients with cardiac devices should now have the same access to MRI scanning in the National Health Service as the general population. Provision of MRI to patients with CIED, however, remains limited in the UK, with only half of units accepting scan requests even for patients with MR Conditional CIEDs. Service delivery requires specialist equipment and robust protocols to ensure patient safety and facilitate workflows, meanwhile demanding collaboration between healthcare professionals across many disciplines. This document provides consensus recommendations from across the relevant stakeholder professional bodies and patient groups to encourage provision of safe MRI for patients with CIEDs.

SCMR expert consensus statement for cardiovascular magnetic resonance of patients with a cardiac implantable electronic device

Cardiovascular magnetic resonance (CMR) is a proven imaging modality for informing diagnosis and prognosis, guiding therapeutic decisions, and risk stratifying surgical intervention. Patients with a cardiac implantable electronic device (CIED) would be expected to derive particular benefit from CMR given high prevalence of cardiomyopathy and arrhythmia. While several guidelines have been published over the last 16 years, it is important to recognize that both the CIED and CMR technologies, as well as our knowledge in MR safety, have evolved rapidly during that period. Given increasing utilization of CIED over the past decades, there is an unmet need to establish a consensus statement that integrates latest evidence concerning MR safety and CIED and CMR technologies. While experienced centers currently perform CMR in CIED patients, broad availability of CMR in this population is lacking, partially due to limited availability of resources for programming devices and appropriate monitoring, but also related to knowledge gaps regarding the risk-benefit ratio of CMR in this growing population. To address the knowledge gaps, this SCMR Expert Consensus Statement integrates consensus guidelines, primary data, and opinions from experts across disparate fields towards the shared goal of informing evidenced-based decision-making regarding the risk-benefit ratio of CMR for patients with CIEDs.

Magnetic resonance imaging in patients with implanted cardiac electrotherapy devices: a statement from experts of the Polish Medical Society of Radiology, the Polish Society of Cardiology, and the Polish Society of Electroradiology

The year 2023 marks 60 years since the first pacemaker was implanted in Poland. The number of implantable cardiac electrotherapy devices (CIEDs), including pacemakers, cardioverter-defibrillators, and resynchronization therapy systems, has been systematically increasing in the subsequent decades. It is estimated that nearly 500,000 Poles have an implanted cardiac electrotherapy device, making optimal diagnostic imaging with the use of magnetic resonance imaging (MRI) a clinically and epidemiologically important issue. MRI has become a gold diagnostic standard in many disease states. In this situation, it is believed that 50-70% of patients who have a cardiac electrotherapy device may have indications for an MRI examination later in life. For many years, an implanted cardiac electrotherapy device was considered a definite contraindication to MRI. However, MRI has become possible in most patients with CIED if certain procedures and precautions are followed. In these guidelines, we describe the basic rules that should be followed in order to perform a safe MRI examination in patients with different CIEDs. Despite all the risks and organizational factors described in the text, it seems that for many MRI departments, MRI in patients with CIEDs is achievable and should be implemented immediately. A second important issue is the need for dedicated financial support for these procedures from public health insurance.

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).

Multicenter retrospective evaluation of magnetic resonance imaging in pediatric and congenital heart disease patients with cardiac implantable electronic devices

BACKGROUND

Guidelines addressing magnetic resonance imaging (MRI) in patients with cardiac implantable electronic devices (CIEDs) provide algorithms for imaging pediatric and congenital heart disease (CHD) patients. Guideline acceptance varies by institution. Guidelines also do not support routine MRI scans in patients with epicardial or abandoned leads, common in pediatric and CHD patients.

OBJECTIVE

The purpose of this study was to determine the incidence of MRI-related complications in pediatric and CHD patients with CIEDs, including epicardial and/or abandoned leads.

METHODS

A multicenter retrospective review included patients with CIEDs who underwent any MRI between 2007 and 2022 at congenital cardiac centers. The primary outcome was any patient adverse event or clinically significant CIED change after MRI, defined as pacing lead capture threshold increase >0.5 V with output change, P- or R- wave amplitude decrease >50% with sensitivity change, or impedance change >50%.

RESULTS

Across 14 institutions, 314 patients (median age 18.8 [1.3; 31.4] years) underwent 389 MRIs. There were 288 pacemakers (74%) and 87 implantable cardioverter-defibrillators (22%); 52% contained epicardial leads, and 14 (4%) were abandoned leads only. Symptoms or CIED changes occurred in 4.9% of MRI scans (6.1% of patients). On 9 occasions (2%), warmth or pain occurred. Pacing capture threshold or lead impedance changes occurred in 1.4% and 2.0% of CIEDs post-MRI and at follow-up.

CONCLUSION

Our data provide evidence that MRIs can be performed in pediatric and CHD patients with CIEDs, including non-MRI-conditional CIEDs and epicardial and/or abandoned leads, with rare minor symptoms or CIED changes but no other complications.

Multimodality Imaging in Differentiating Constrictive Pericarditis From Restrictive Cardiomyopathy: A Comprehensive Overview for Clinicians and Imagers

In the evaluation of heart failure, 2 differential diagnostic considerations include constrictive pericarditis and restrictive cardiomyopathy. The often outwardly similar clinical presentation of these 2 pathologic entities routinely renders their clinical distinction difficult. Consequently, initial assessment requires a keen understanding of their separate pathophysiology, epidemiology, and hemodynamic effects. Following a detailed clinical evaluation, further assessment initially rests on comprehensive echocardiographic investigation, including detailed Doppler evaluation. With the combination of mitral inflow characterization, tissue Doppler assessment, and hepatic vein interrogation, initial differentiation of constrictive pericarditis and restrictive cardiomyopathy is often possible with high sensitivity and specificity. In conjunction with a compatible clinical presentation, successful differentiation enables both an accurate diagnosis and subsequent targeted management. In certain cases, however, the diagnosis remains unclear despite echocardiographic assessment, and additional evaluation is required. With advances in noninvasive tools, such evaluation can often continue in a stepwise, algorithmic fashion noninvasively, including both cross-sectional and nuclear imaging. Should this additional evaluation itself prove insufficient, invasive assessment with appropriate expertise may ultimately be necessary.

Cardiac Magnetic Resonance, Electromechanical Activation, Kidney Function, and Natriuretic Peptides in Cardiac Resynchronization Therapy Upgrades

As the mechanism for worse prognosis after cardiac resynchronization therapy (CRT) upgrades in heart failure patients with RVP dependence (RVP-HF) has clinical implications for patient selection and CRT implementation approaches, this study's objective was to evaluate prognostic implications of cardiac magnetic resonance (CMR) findings and clinical factors in 102 HF patients (23.5% female, median age 66.5 years old, median follow-up 4.8 years) with and without RVP dependence undergoing upgrade and de novo CRT implants. Compared with other CRT groups, RVP-HF patients had decreased survival (p = 0.02), more anterior late-activated LV pacing sites (p = 0.002) by CMR, more atrial fibrillation (p = 0.0006), and higher creatinine (0.002). CMR activation timing at the LV pacing site predicted post-CRT LV functional improvement (p < 0.05), and mechanical activation onset < 34 ms by CMR at the LVP site was associated with decreased post-CRT survival in a model with higher pre-CRT creatinine and B-type natriuretic peptide (AUC 0.89; p < 0.0001); however, only the higher pre-CRT creatinine partially mediated (37%) the decreased survival in RVP-HF patients. In conclusion, RVP-HF had a distinct CMR phenotype, which has important implications for the selection of LV pacing sites in CRT upgrades, and only chronic kidney disease mediated the decreased survival after CRT in RVP-HF.

Brain imaging with portable low-field MRI

The advent of portable, low-field MRI (LF-MRI) heralds new opportunities in neuroimaging. Low power requirements and transportability have enabled scanning outside the controlled environment of a conventional MRI suite, enhancing access to neuroimaging for indications that are not well suited to existing technologies. Maximizing the information extracted from the reduced signal-to-noise ratio of LF-MRI is crucial to developing clinically useful diagnostic images. Progress in electromagnetic noise cancellation and machine learning reconstruction algorithms from sparse k-space data as well as new approaches to image enhancement have now enabled these advancements. Coupling technological innovation with bedside imaging creates new prospects in visualizing the healthy brain and detecting acute and chronic pathological changes. Ongoing development of hardware, improvements in pulse sequences and image reconstruction, and validation of clinical utility will continue to accelerate this field. As further innovation occurs, portable LF-MRI will facilitate the democratization of MRI and create new applications not previously feasible with conventional systems.

Interventional cardiovascular magnetic resonance: state-of-the-art

Transcatheter cardiovascular interventions increasingly rely on advanced imaging. X-ray fluoroscopy provides excellent visualization of catheters and devices, but poor visualization of anatomy. In contrast, magnetic resonance imaging (MRI) provides excellent visualization of anatomy and can generate real-time imaging with frame rates similar to X-ray fluoroscopy. Realization of MRI as a primary imaging modality for cardiovascular interventions has been slow, largely because existing guidewires, catheters and other devices create imaging artifacts and can heat dangerously. Nonetheless, numerous clinical centers have started interventional cardiovascular magnetic resonance (iCMR) programs for invasive hemodynamic studies or electrophysiology procedures to leverage the clear advantages of MRI tissue characterization, to quantify cardiac chamber function and flow, and to avoid ionizing radiation exposure. Clinical implementation of more complex cardiovascular interventions has been challenging because catheters and other tools require re-engineering for safety and conspicuity in the iCMR environment. However, recent innovations in scanner and interventional device technology, in particular availability of high performance low-field MRI scanners could be the inflection point, enabling a new generation of iCMR procedures. In this review we review these technical considerations, summarize contemporary clinical iCMR experience, and consider potential future applications.

Noninvasive Assessment of Lipomatous Metaplasia as a Substrate for Ventricular Tachycardia in Chronic Infarct

Myocardial lipomatous metaplasia (LM) has been increasingly reported in patients with prior myocardial infarction. Cardiac magnetic resonance and cardiac contrast-enhanced computed tomography have been used to noninvasively detect and quantify myocardial LM in postinfarct patients, and may provide useful information for understanding cardiac mechanics, arrhythmia susceptibility, and prognosis. This review aims to summarize the advantages and disadvantages, clinical applications, and imaging features of different cardiac magnetic resonance sequences and cardiac contrast-enhanced computed tomography for LM detection and quantification. We also briefly summarize LM prevalence in different cohorts of postinfarct patients and review the clinical utility of cardiac imaging in exploring myocardial LM as an arrhythmogenic substrate in patients with prior myocardial infarction.

Cardiothoracic and Vascular Surgery Implant Compatibility With Ultrahigh Field Magnetic Resonance Imaging (4.7 Tesla and 7 Tesla)

The use of 7 Tesla (T) magnetic resonance imaging (MRI) is expanding across medical specialties, particularly, clinical neurosciences and orthopedics. Investigational 7 T MRI has also been performed in cardiology. A limiting factor for expansion of the role of 7 T, irrespective of the body part being imaged, is the sparse testing of biomedical implant compatibility at field strengths >3 T. Implant compatibility can be tested following the American Society for Testing and Materials International guidelines. To assess the current state of cardiovascular implant safety at field strengths >3 T, a systematic search was performed using PubMed, Web of Science, and citation matching. Studies written in English that included at least 1 cardiovascular-related implant and at least 1 safety outcome (deflection angle, torque, or temperature change) were included. Data were extracted for the implant studied, implant composition, deflection angle, torque, and temperature change, and the American Society for Testing and Materials International standards were followed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines for scoping reviews were followed. A total of 9 studies were included. A total of 34 cardiovascular-related implants tested ex vivo at 7 T and 91 implants tested ex vivo at 4.7 T were included. The implants included vascular grafts and conduits, vascular access ports, peripheral and coronary stents, caval filters, and artificial valves. A total of 2 grafts, 1 vascular access port, 2 vena cava filters, and 5 stents were identified as incompatible with the 7 T MRI. All incompatible stents were 40 mm in length. Based on the safety outcomes reported, we identify several implants that may be compatible with >3 T MRI. This scoping review seeks to concisely summarize all the cardiovascular-related implants tested for ultrahigh field MRI compatibility to date.

Imaging of Hepatobiliary Cancer

The liver and biliary tree are common sites of primary and secondary malignancies. MRI followed by CT is the mainstay for the imaging characterization of these malignancies with the dynamically acquired contrast enhanced phases being the most important for diagnosis. The liver imaging reporting and data system classification provides a useful framework for reporting lesions in patents with underlying cirrhosis or who are at high risk for developing hepatocellular carcinoma. Detection of metastases is improved with the use of liver specific MRI contrast agents and diffusion weighted sequences. Aside from hepatocellular carcinoma, which is often diagnosed noninvasively, other primary hepatobiliary tumors may require biopsy for definite diagnosis, especially when presenting with nonclassic imaging findings. In this review, we examine the imaging findings of common and less common hepatobiliary tumors.

MRI safety screening of children with implants: updates and challenges

MRI is the imaging modality of choice for assessing many pediatric medical conditions. Although there are several inherent potential safety risks associated with the electromagnetic fields exploited for MRI, they are effectively mitigated through strict adherence to established MRI safety practices, enabling the safe and effective use of MRI in clinical practice. The potential hazards of the MRI environment may be exacerbated by/in the presence of implanted medical devices. Awareness of the unique MRI safety and screening challenges associated with these implanted devices is critical to ensuring MRI safety for the affected patients. In this review article, we will discuss the basics of MRI physics as they relate to MRI safety in the presence of implanted medical devices, strategies for assessing children with known or suspected implanted medical devices, and the particular management of several well-established common, as well as recently developed, implanted devices encountered at our institution.

Implantable Defibrillator System Shock Function, Mortality, and Cause of Death After Magnetic Resonance Imaging

BACKGROUND

Studies have shown that magnetic resonance imaging (MRI) does not have clinically important effects on the device parameters of non-MRI-conditional implantable cardioverter-defibrillators (ICDs). However, data on non-MRI-conditional ICD detection and treatment of arrhythmias after MRI are limited.

OBJECTIVE

To examine if non-MRI-conditional ICDs have preserved shock function of arrhythmias after MRI.

DESIGN

Prospective cohort study. (ClinicalTrials.gov: NCT01130896).

SETTING

1 center in the United States.

PATIENTS

629 patients with non-MRI-conditional ICDs enrolled consecutively between February 2003 and January 2015.

INTERVENTIONS

813 total MRI examinations at a magnetic field strength of 1.5 Tesla using a prespecified safety protocol.

MEASUREMENTS

Implantable cardioverter-defibrillator interrogations were collected after MRI. Clinical outcomes included arrhythmia detection and treatment, generator or lead exchanges, adverse events, and death.

RESULTS

During a median follow-up of 2.2 years from MRI to latest available ICD interrogation before generator or lead exchange in 536 patients, 4177 arrhythmia episodes were detected, and 97 patients received ICD shocks. Sixty-one patients (10% of total) had 130 spontaneous ventricular tachycardia or fibrillation events terminated by ICD shocks. A total of 210 patients (33% of total) are known to have died (median, 1.7 years from MRI to death); 3 had cardiac arrhythmia deaths where shocks were indicated without direct evidence of device dysfunction.

LIMITATIONS

Data were acquired at a single center and may not be generalizable to other clinical settings and MRI facilities. Implantable cardioverter-defibrillator interrogations were not available for a subset of patients; adjudication of cause of death relied solely on death certificate data in a subset.

CONCLUSION

Non-MRI-conditional ICDs appropriately treated detected tachyarrhythmias after MRI. No serious adverse effects on device function were reported after MRI.

PRIMARY FUNDING SOURCE

Johns Hopkins University and National Institutes of Health.

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.

Safety, feasibility, and prognostic value of stress perfusion CMR in patients with MR-conditional pacemaker

AIMS

To assess the safety, feasibility, and prognostic value of stress cardiovascular magnetic resonance (CMR) in patients with pacemaker (PM).

METHODS AND RESULTS

Between 2008 and 2021, we conducted a bi-centre longitudinal study with all consecutive patients with MR-conditional PM referred for vasodilator stress CMR at 1.5 T in the Institut Cardiovasculaire Paris Sud and Lariboisiere University Hospital. They were followed for the occurrence of major adverse cardiovascular events (MACE) defined as cardiac death or non-fatal myocardial infarction. Cox regression analyses were performed to determine the prognostic value of CMR parameters. The quality of CMR was rated by two observers blinded to clinical details. Of 304 patients who completed the CMR protocol, 273 patients (70% male, mean age 71 ± 9 years) completed the follow-up (median [interquartile range], 7.1 [5.4-7.5] years). Among those, 32 experienced a MACE (11.7%). Stress CMR was well tolerated with no significant change in lead thresholds or pacing parameters. Overall, the image quality was rated good or excellent in 84.9% of segments. Ischaemia and late gadolinium enhancement (LGE) were significantly associated with the occurrence of MACE (hazard ratio, HR: 11.71 [95% CI: 4.60-28.2]; and HR: 5.62 [95% CI: 2.02-16.21], both P < 0.001). After adjustment for traditional risk factors, ischaemia and LGE were independent predictors of MACE (HR: 5.08 [95% CI: 2.58-14.0]; and HR: 2.28 [95% CI: 2.05-3.76]; both P < 0.001).

CONCLUSION

Stress CMR is safe, feasible and has a good discriminative prognostic value in consecutive patients with PM.

Impact of wideband cardiac magnetic resonance on diagnosis, decision-making and outcomes in patients with implantable cardioverter defibrillators

AIMS

Although myocardial scar assessment using late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging is frequently indicated for patients with implantable cardioverter defibrillators (ICDs), metal artefact can degrade image quality. With the new wideband technique designed to mitigate device related artefact, CMR is increasingly used in this population. However, the common clinical indications for CMR referral and impact on clinical decision-making and prognosis are not well defined. Our study was designed to address these knowledge gaps.

METHODS AND RESULTS

One hundred seventy-nine consecutive patients with an ICD (age 59 ± 13 years, 75% male) underwent CMR using cine and wideband pulse sequences for LGE imaging. Electronic medical records were reviewed to determine the reason for CMR referral, whether there was a change in clinical decision-making, and occurrence of major adverse cardiac events (MACEs). Referral indication was the most common evaluation of ventricular tachycardia (VT) substrate (n = 114, 64%), followed by cardiomyopathy (n = 53, 30%). Overall, CMR resulted in a new or changed diagnosis in 64 (36%) patients and impacted clinical management in 51 (28%). The effect on management change was highest in patients presenting with VT. A total of 77 patients (43%) experienced MACE during the follow-up period (median 1.7 years), including 65 in patients with evidence of LGE. Kaplan-Meier analysis showed that ICD patients with LGE had worse outcomes than those without LGE (P = 0.006).

CONCLUSION

The clinical yield from LGE CMR is high and provides management changing and meaningful prognostic information in a significant proportion of patients with ICDs.

Experience of 500 cardiovascular magnetic resonance imaging and systematic analysis of cases

OBJECTIVE

Cardiovascular magnetic resonance imaging (MRI) is a widely accepted reference imaging technique in routine cardiology clinics in many centers due to its advantages in providing preferable functional, morphologic information. However, there is little information about national experience in clinical application and findings of cardiovascular MRI. The objective of this study was to demonstrate the clinical and demographic characteristics of patients admitted to our cardiac imaging department.

METHODS

A total of 500 cardiovascular MRI examinations performed between 2016 and 2019 were enrolled in this retrospective study. Clinical indications, demographic, and cardiovascular MRI findings of the patients were retrospectively evaluated.

RESULTS

Five hundred patients (M/F=301/199) were included in this retrospective, single center study. The majority of the examinations were performed for the assessment of congenital heart disease (n=254, 50.8%). The other indications were for myocardial disease (n=160, 32%), cardiac mass (n=44, 8.8%), valvular heart disease (n=20, 4%), magnetic resonance angiography (n=12, 2.4% for aorta and pulmonary artery [n=9, 1.8%] and for coronary arteries [n=3, 0.6%]), and vasculitis (n=7, 1.7%), pericardial disease (n=3, 0.6%). Minor complication was seen during the contrast agent injection in three patients (0.06%).

CONCLUSION

Cardiovascular MRI is a reliable and accurate imaging tool in identifying the various cardiac pathology with widely accepted use in the clinical area. Our single-center experience of 500 cases demonstrates the varieties of clinical indications in daily practice that may contribute to the national data pool.

Left Ventricular Apical Aneurysm in Fabry Disease: Implications for Clinical Significance and Risk Stratification

Background A previously underrecognized phenotype of left ventricular apical aneurysm (LVAA) has been increasingly identified in Fabry disease. This study explored LVAA's clinical prevalence and its prognostic implications over a long-term follow-up. Methods and Results We retrospectively analyzed 268 consecutive patients with Fabry disease at a tertiary medical center. Patients with increased left ventricular mass index were recognized as having left ventricular hypertrophy (LVH). LVAA was identified using either echocardiography or cardiovascular magnetic resonance imaging. Two patients with ischemic LVAA were excluded. The primary end point was a composite of cardiovascular events, including heart failure hospitalization, sustained ventricular tachycardia, ischemic stroke, and all-cause mortality. Of 266 enrolled patients, 105 (39.5%) had LVH (age 58.5±11.9 years, 48.6% men), and 11 (10.5%) had LVAA. Over 49.3±34.8 months of follow-up, 25 patients with LVH experienced composite events, including 9 heart failure hospitalizations, 4 sustained ventricular tachycardia, 6 ischemic strokes, and 15 mortalities. In patients with LVH, those with LVAA had a significantly higher risk of composite events and lower event-free survival than those without LVAA (8 [72.7%] versus 17 [18.1%], log-rank P<0.001). LVAA was independently associated with an increased risk of composite events (hazard ratio, 3.59 [95% CI, 1.30-9.91]; P=0.01) after adjusting for age, sex, advanced heart failure, renal function, dyslipidemia, atrial fibrillation, left ventricular ejection fraction, left ventricular diastolic function, and left ventricular mass index. Conclusions LVAA is present in approximately 10% of patients with Fabry disease and LVH. It is associated with an increased risk of adverse cardiovascular events and may necessitate aggressive treatment.

Practical Approaches to Transvenous Lead Extraction Procedures-Clinical Case Series

Transvenous lead extraction (TLE) is regarded as the first-line strategy for the management of complications associated with cardiac implantable electronic devices (CIEDs), when lead removal is mandatory. The decision to perform a lead extraction should take into consideration not only the strength of the clinical indication for the procedure but also many other factors such as risks versus benefits, extractor and team experience, and even patient preference. TLE is a procedure with a possible high risk of complications. In this paper, we present three clinical cases of patients who presented different indications of TLE and explain how the procedures were successfully performed. In the first clinical case, TLE was necessary because of device extravasation and suspicion of CIED pocket infection. In the second clinical case, TLE was necessary because occlusion of the left subclavian vein was found when an upgrade to cardiac resynchronization therapy was performed. In the last clinical case, TLE was necessary in order to remove magnetic resonance (MR) non-conditional leads, so the patient could undergo an MRI examination for the management of a brain tumor.

Magnetic resonance imaging in patients with temporary external pacemakers

AIMS

To describe safety and feasibility of magnetic resonance imaging (MRI) in patients with transvenous temporary external pacemakers and whether artefacts affect the diagnostic image quality during cardiac MRI.

METHODS AND RESULTS

We reviewed records of all patients treated with temporary external pacing between 2016 and 2020 at a tertiary centre. Temporary pacing was established using a transvenous standard active fixation pacing lead inserted percutaneously and connected to a MRI-conditional pacemaker taped to the skin. All patients undergoing cardiac or non-cardiac MRI during temporary transvenous pacing were identified. Before MRI, devices were programmed according to guidelines for permanent pacemakers, and patients were monitored with continuous electrocardiogram during MRI. Of 827 consecutive patients receiving a temporary external pacemaker, a total of 44 (5%) patients underwent MRI (mean age 71 years, 13 [30%] females). Cardiac MRI was performed in 22 (50%) patients, while MRI of cerebrum, spine, and other regions was performed in the remaining patients. Median time from implantation of the temporary device to MRI was 6 (3-11) days. During MRI, we observed no device-related malfunction or arrhythmia. Nor did we detect any change in lead sensing, impedance, or pacing threshold. We observed no artefacts from the lead or pacemaker compromising the diagnostic image quality of cardiac MRI. MRI provided information to guide the clinical management in all cases.

CONCLUSION

MRI is feasible and safe in patients with temporary external pacing established with a regular MRI-conditional pacemaker and a standard active fixation lead. No artefacts compromised the diagnostic image quality.

Understanding Delays in MRI-based Selection of Large Vessel Occlusion Stroke Patients for Endovascular Thrombectomy

PURPOSE

Given the efficacy of endovascular thrombectomy (EVT), optimizing systems of delivery is crucial. Magnetic resonance imaging (MRI) is the gold standard for evaluating tissue viability but may require more time to obtain and interpret. We sought to identify determinants of arrival-to-puncture time for patients who underwent MRI-based EVT selection in a real-world setting.

METHODS

Patients were identified from a prospectively maintained database from 2011-2019 that included demographics, presentations, treatments, and outcomes. Process times were obtained from the medical charts. MRI times were obtained from time stamps on the first sequence. Linear and logistic regressions were used to infer explanatory variables of arrival-to-puncture times and effects of arrival-to-puncture time on functional outcomes.

RESULTS

In this study 192 patients (median age 70 years, 57% women, 12% non-white) underwent MRI-based EVT selection. 66% also underwent computed tomography (CT) at the hub before EVT. General anesthesia was used for 33%. Among the entire cohort, the median arrival-to-puncture was 102 min; however, among those without CT it was 77 min. Longer arrival-to-puncture times independently reduced the odds of 90-day good outcome (∆mRS ≤ 2 from pre-stroke, aOR = 0.990, 95%CI = 0.981-0.999, p = 0.040) when controlling for age, NIHSS, and good reperfusion (TICI 2b-3). Independent determinants of longer arrival-to-puncture were CT plus MRI (β = 0.205, p = 0.003), non-white race/ethnicity (β = 0.162, p = 0.012), coronary disease (β = 0.205, p = 0.001), and general anesthesia (β = 0.364, p < 0.0001).

CONCLUSION

Minimizing arrival-to-puncture time is important for outcomes. Real-world challenges exist in an MRI-based EVT selection protocol; avoiding double imaging is key to saving time. Racial/ethnic disparities require further study. Understanding variables associated with delay will inform protocol changes.

3 Tesla magnetic resonance imaging in patients with cardiac implantable electronic devices: a single centre experience

AIMS

Three Tesla (T) magnetic resonance imaging (MRI) provides critical imaging information for many conditions. Owing to potential interactions of the magnetic field, it is largely withheld from patients with cardiac implantable electronic devices (CIEDs). Therefore, we assessed the safety of 3T MRI in patients with '3T MRI-conditional' and 'non-3T MRI-conditional' CIEDs.

METHODS AND RESULTS

We performed a retrospective single-centre analysis of clinically indicated 3T MRI examinations in patients with conventional pacemakers, cardiac resynchronization devices, and implanted defibrillators from April 2020 to May 2022. All CIEDs were interrogated and programmed before and after scanning. Adverse events included all-cause death, arrhythmias, loss of capture, inappropriate anti-tachycardia therapies, electrical reset, and lead or generator failure during or shortly after MRI. Changes in signal amplitude and lead impedance were systematically assessed. Statistics included median and interquartile range. A total of 132 MRI examinations were performed on a 3T scanner in 97 patients. Thirty-five examinations were performed in patients with 'non-3T MRI-conditional' CIEDs. Twenty-six scans were performed in pacemaker-dependent patients. No adverse events occurred during or shortly after MRI. P-wave or R-wave reductions ≥ 50 and ≥ 25%, respectively, were noted after three (2.3%) scans, all in patients with '3T MRI-conditional' CIEDs. Pacing and shock impedance changed by ± 30% in one case (0.7%). Battery voltage and stimulation thresholds did not relevantly change after MRI.

CONCLUSION

Pending verification in independent series, our data suggest that clinically indicated MRI scans at 3T field strength should not be withheld from patients with cardiac pacemakers or defibrillators.

Lipomatous Metaplasia Enables Ventricular Tachycardia by Reducing Current Loss Within the Protected Corridor

BACKGROUND

Post-myocardial infarction ventricular tachycardia (VT) is due to re-entry through surviving conductive myocardial corridors across infarcted tissue. However, not all conductive corridors participate in re-entry.

OBJECTIVES

This study sought to test the hypothesis that critical VT corridors are more likely to traverse near lipomatous metaplasia (LM) and that current loss is reduced during impulse propagation through such corridors.

METHODS

Among 30 patients in the Prospective 2-center INFINITY (Intra-Myocardial Fat Deposition and Ventricular Tachycardia in Cardiomyopathy) study, potential VT-viable corridors within myocardial scar or LM were computed from late gadolinium enhancement cardiac magnetic resonance images. Because late gadolinium enhancement highlights both scar and LM, LM was distinguished from scar by using computed tomography. The SD of the current along each corridor was measured.

RESULTS

Scar exhibited lower impedance than LM (median Z-score -0.22 [IQR: -0.84 to 0.35] vs -0.07 [IQR: -0.67 to 0.54]; P < 0.001). Among all 381 corridors, 84 were proven to participate in VT re-entry circuits, 83 (99%) of which traversed or were adjacent to LM. In comparison, only 13 (4%) non-VT corridors were adjacent to LM. Critical corridors adjacent to LM displayed lower SD of current compared with noncritical corridors through scar but distant from LM (2.0 [IQR: 1.0 to 3.4] μA vs 8.4 [IQR: 5.5 to 12.8] μA; P < 0.001).

CONCLUSIONS

Corridors critical to VT circuitry traverse infarcted tissue through or near LM. This association is likely mediated by increased regional resistance and reduced current loss as impulses traverse corridors adjacent to LM.

Trends in Utilization of Magnetic Resonance Imaging for Stroke Patients With Cardiac Rhythm Devices

Background and Purpose

Magnetic resonance imaging (MRI) is safe for most patients with cardiovascular implantable electronic devices (CIEDs). However, patients presenting with acute ischemic stroke or transient ischemic attack (AIS/TIA) who have CIEDs may undergo MRI less frequently than patients without devices. We assessed contemporary use of MRI for patients with AIS/TIA and the effect of a recent coverage revision by the Center for Medicare and Medicaid Services (CMS) on MRI utilization.

Methods

Using Optum® claims data from January 2012 to June 2019, we performed an interrupted time series analysis of MRI utilization during AIS/TIA hospitalizations with the April 2018 CMS coverage revision serving as the intervention. For patients treated after the coverage revision, we used multivariable logistic regression to determine the association between lack of CIED and MRI utilization for AIS/TIA.

Results

We identified 417,899 patient hospitalizations for AIS/TIA, of which 30,425 (7%) had a CIED present (CIED vs non-CIED patients: age 77.6 ± 9.8 vs 72.7 ± 12.3 years; 45.5% vs 54.3% female). From 2012 to 2019, annual MRI utilization increased from 3% to 20% for CIED patients and 58% to 66% for non-CIED patients. The CMS coverage revision was associated with a 4.2% absolute additional increase in MRI utilization for CIED patients. Non-CIED patients treated after the CMS coverage revision were substantially more likely than CIED patients to undergo MRI (adjusted OR 6.7, 95% CI: 6.3-7.1, P<.001).

Conclusions

MRI utilization has increased for stroke patients with CIEDs but remains far lower than in similar patients without devices.

ED MRI: Safety, Consent, and Regulatory Considerations

MRI is a vital examination in the emergency department, especially in patients with stroke, spinal cord compression, cardiovascular emergencies, appendicitis, and trauma. It is important to consider its underlying safety hazards because of its strong magnetic and radio frequency fields. Multiple resources are available to guide radiology departments on the safe functioning of an MRI site. Four-zone site layout, MR compatibility labeling, MR personnel training, detailed screening process, access control, and appropriate implementation of safety policies and procedures are all necessary to maintain a safe and hazard-free MR environment.

Cardiac Magnetic Resonance Imaging-Based Screening for Cardiac Sarcoidosis in Patients With Atrioventricular Block Requiring Temporary Pacing

Background Some myocardial diseases, such as cardiac sarcoidosis, predispose to complete atrioventricular block. The European Society of Cardiology Guidelines on cardiac pacing in 2021 recommend myocardial disease screening in patients with conduction disorder requiring pacemaker with multimodality imaging, including cardiac magnetic resonance (CMR) imaging. The ability of CMR imaging to detect myocardial disease in patients with a temporary pacing wire is not well documented. Methods and Results Our myocardial disease screening protocol is based on using an active fixation pacing lead connected to a reusable extracorporeal pacing generator (temporary permanent pacemaker) as a bridge to a permanent pacemaker. From 2011 to 2019, we identified 17 patients from our CMR database who underwent CMR imaging with a temporary permanent pacemaker for atrioventricular block. We analyzed their clinical presentations, CMR data, and pacemaker therapy. All CMRs were performed without adverse events. Pacing leads induced minor artifacts to the septal myocardial segments. The extent of late gadolinium enhancement in CMR imaging was used to screen patients for the presence of myocardial disease. Patients with evidence of late gadolinium enhancement underwent endomyocardial biopsy. If considered clinically indicated, also 18-F-fluorodeoxyglucose positron emission tomography and extracardiac tissue biopsy were performed if sarcoidosis was suspected. Eventually, 8 of 17 patients (47.1%) were diagnosed with histologically confirmed granulomatous inflammatory cardiac disease. Importantly, only 1 had a previously diagnosed extracardiac sarcoidosis at the time of presentation with high-degree atrioventricular block. Conclusions CMR imaging with temporary permanent pacemaker protocol is an effective and safe early screening tool for myocardial disease in patients presenting with atrioventricular block requiring immediate, continuous pacing for bradycardia.

Nachsorge und MRT-Untersuchungen bei Patienten mit implantierten kardialen Aggregaten

In den 2021 publizierten ESC-Leitlinien wird im Rahmen des Kapitels über die Aggregatnachsorge insbesondere die Bedeutung der Telemetrie hervorgehoben. Durch eine telemetrische Nachsorge sind wesentlich seltener Präsenznachsorgen notwendig bei gleichwertiger oder sogar verbesserter Sicherheit. Eine telemetrische Überwachung sollte daher bei allen Patienten mit CIED erwogen werden.

Die Leitlinien beschreiben detailliert die Möglichkeiten und Einschränkungen von MRT-Untersuchungen bei Patienten mit CIED. Programmierempfehlungen für die verschiedenen Hersteller werden dargestellt. Unter Einhaltung entsprechender Sicherheitsstandards kann eine MRT auch ohne größeres Risiko bei Patienten mit nicht MRT-kompatiblen Systemen erfolgen.