1
|
Oebel S, Jahnke C, Bode K, Paetsch I. Electrophysiological Cardiovascular Magnetic Resonance (EP-CMR)-Guided Interventional Procedures: Challenges and Opportunities. Curr Cardiol Rep 2024; 26:903-910. [PMID: 39023800 DOI: 10.1007/s11886-024-02092-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/02/2024] [Indexed: 07/20/2024]
Abstract
PURPOSE OF REVIEW Cardiovascular magnetic resonance (CMR) imaging excels in providing detailed three-dimensional anatomical information together with excellent soft tissue contrast and has already become a valuable tool for diagnostic evaluation, electrophysiological procedure (EP) planning, and therapeutical stratification of atrial or ventricular rhythm disorders. CMR-based identification of ablation targets may significantly impact existing concepts of interventional electrophysiology. In order to exploit the inherent advantages of CMR imaging to the fullest, CMR-guided ablation procedures (EP-CMR) are justly considered the ultimate goal. RECENT FINDINGS Electrophysiological cardiovascular magnetic resonance (EP-CMR) interventional procedures have more recently been introduced to the CMR armamentarium: in a single-center series of 30 patients, an EP-CMR guided ablation success of 93% has been reported, which is comparable to conventional ablation outcomes for typical atrial flutter and procedure and ablation time were also reported to be comparable. However, moving on from already established workflows for the ablation of typical atrial flutter in the interventional CMR environment to treatment of more complex ventricular arrhythmias calls for technical advances regarding development of catheters, sheaths and CMR-compatible defibrillator equipment. CMR imaging has already become an important diagnostic tool in the standard clinical assessment of cardiac arrhythmias. Previous studies have demonstrated the feasibility and safety of performing electrophysiological interventional procedures within the CMR environment and fully CMR-guided ablation of typical atrial flutter can be implemented as a routine procedure in experienced centers. Building upon established workflows, the market release of new, CMR-compatible interventional devices may finally enable targeting ventricular arrhythmias.
Collapse
Affiliation(s)
- Sabrina Oebel
- Department of Electrophysiology, HELIOS Heart Center Leipzig at University of Leipzig, Struempellstr. 39, 04289, Leipzig, Germany.
| | - Cosima Jahnke
- Department of Electrophysiology, HELIOS Heart Center Leipzig at University of Leipzig, Struempellstr. 39, 04289, Leipzig, Germany
| | - Kerstin Bode
- Department of Electrophysiology, HELIOS Heart Center Leipzig at University of Leipzig, Struempellstr. 39, 04289, Leipzig, Germany
| | - Ingo Paetsch
- Department of Electrophysiology, HELIOS Heart Center Leipzig at University of Leipzig, Struempellstr. 39, 04289, Leipzig, Germany
| |
Collapse
|
2
|
Rogers T, Campbell-Washburn AE, Ramasawmy R, Yildirim DK, Bruce CG, Grant LP, Stine AM, Kolandaivelu A, Herzka DA, Ratnayaka K, Lederman RJ. Interventional cardiovascular magnetic resonance: state-of-the-art. J Cardiovasc Magn Reson 2023; 25:48. [PMID: 37574552 PMCID: PMC10424337 DOI: 10.1186/s12968-023-00956-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
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.
Collapse
Affiliation(s)
- Toby Rogers
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA.
- Section of Interventional Cardiology, MedStar Washington Hospital Center, 110 Irving St NW, Suite 4B01, Washington, DC, 20011, USA.
| | - Adrienne E Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - Rajiv Ramasawmy
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - D Korel Yildirim
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - Christopher G Bruce
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - Laurie P Grant
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - Annette M Stine
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - Aravindan Kolandaivelu
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
- Johns Hopkins Hospital, Baltimore, MD, USA
| | - Daniel A Herzka
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
| | - Kanishka Ratnayaka
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA
- Rady Children's Hospital, San Diego, CA, USA
| | - Robert J Lederman
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/Room 2C713, 9000 Rockville Pike, Bethesda, MD, 20892-1538, USA.
| |
Collapse
|
3
|
Oebel S, Jahnke C, Hindricks G, Paetsch I. Nutzen der kardialen Magnetresonanzdiagnostik für Patienten mit Herzrhythmusstörungen. Herz 2022; 47:110-117. [DOI: 10.1007/s00059-022-05105-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2022] [Indexed: 11/28/2022]
|
4
|
Schmidt EJ, Elahi H, Meyer ES, Baumgaertner R, Neri L, Berger RD, Tandri H, Hunter DW, Cohen SP, Oberdier MT, Halperin HR. Reduced Motion External Defibrillation (RMD): Reduced Subject Motion with Equivalent Defibrillation Efficiency validated in Swine. Heart Rhythm 2022; 19:1165-1173. [PMID: 35240311 DOI: 10.1016/j.hrthm.2022.02.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND External defibrillators are used for arrhythmia cardioversion and for defibrillating during cardiac arrest. During defibrillation, short-duration Biphasic pulses cause intense motion due to rapid chest-wall muscle contraction. A reduced-motion external defibrillator (RMD) was constructed by integrating a commercial defibrillator with a Tetanizing-waveform generator. A long-duration low-amplitude Tetanizing-waveform slowly stimulated the chest musculature prior to the Biphasic pulse, reducing muscle contraction during the shock. OBJECTIVE Evaluate RMD defibrillation in swine for subject-motion during defibrillation pulses and for defibrillation effectiveness. RMD defibrillation can reduce the duration of arrhythmia ablation-therapy or simplify cardioversion procedures. METHODS The Tetanizing unit delivered a triangular 1-kHz pulse of 0.25-2.0sec duration and 10-100Volt peak amplitude, subsequently triggering the conventional defibrillator to output standard 1-200J energy Biphasic pulses at the next R-wave. Forward-limb motion was evaluated by measuring Peak Acceleration and Limb Work during RMD (Tetanizing+Biphasic) or Biphasic-pulse-only waveforms at 10-3sec sampling-rate. Seven swine were arrested electrically and subsequently defibrillated. Biphasic-pulse-only and RMD defibrillations were repeated 25-35 times/swine, varying Tetanizing parameters and the Biphasic-pulse energy. Defibrillation thresholds (DFTs) were established by measuring the minimum energy required to restore sinus-rhythm with Biphasic-pulse-only or RMD defibrillations. RESULTS Two forward-limb acceleration-peaks occurred during both the Tetanizing-waveform and Biphasic-pulse, indicating rapid and slower nociceptic (pain-sensation) nerve-fiber activation. Optimal RMD Tetanizing-parameters (25-35V, 0.25-0.75sec duration), relative to Biphasic-pulse-only defibrillations, resulted in 74+10% smaller Peak Accelerations and 85+10% reduced Limb Work. DFT energies were identical, comparing RMD to Biphasic-pulse-only defibrillations. CONCLUSION Relative to conventional defibrillations, RMD defibrillations maintain rhythm-restoration efficiency with drastically reduced subject-motion.
Collapse
Affiliation(s)
- Ehud J Schmidt
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD.
| | - Hassan Elahi
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD
| | - Eric S Meyer
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD
| | | | - Luca Neri
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD
| | - Ronald D Berger
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD
| | | | - David W Hunter
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD
| | | | - Matt T Oberdier
- Medicine (Cardiology), Johns Hopkins University, Baltimore, MD
| | | |
Collapse
|
5
|
Amin EK, Campbell-Washburn A, Ratnayaka K. MRI-Guided Cardiac Catheterization in Congenital Heart Disease: How to Get Started. Curr Cardiol Rep 2022; 24:419-429. [PMID: 35107702 PMCID: PMC8979923 DOI: 10.1007/s11886-022-01659-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/15/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Cardiac magnetic resonance imaging provides radiation-free, 3-dimensional soft tissue visualization with adjunct hemodynamic data, making it a promising candidate for image-guided transcatheter interventions. This review focuses on the benefits and background of real-time magnetic resonance imaging (MRI)-guided cardiac catheterization, guidance on starting a clinical program, and recent research developments. RECENT FINDINGS Interventional cardiac magnetic resonance (iCMR) has an established track record with the first entirely MRI-guided cardiac catheterization for congenital heart disease reported nearly 20 years ago. Since then, many centers have embarked upon clinical iCMR programs primarily performing diagnostic MRI-guided cardiac catheterization. There have also been limited reports of successful real-time MRI-guided transcatheter interventions. Growing experience in performing cardiac catheterization in the magnetic resonance environment has facilitated practical workflows appropriate for efficiency-focused cardiac catheterization laboratories. Most exciting developments in imaging technology, MRI-compatible equipment and MRI-guided novel transcatheter interventions have been limited to preclinical research. Many of these research developments are ready for clinical translation. With increasing iCMR clinical experience and translation of preclinical research innovations, the time to make the leap to radiation-free procedures is now.
Collapse
Affiliation(s)
- Elena K Amin
- Division of Pediatric Cardiology, UCSF Benioff Children's Hospitals, University of California, San Francisco, San Francisco, CA, USA.
| | - Adrienne Campbell-Washburn
- Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kanishka Ratnayaka
- Division of Pediatric Cardiology, Rady Children's Hospital, University of California, San Diego, 3020 Children's Way, San Diego, CA, USA
| |
Collapse
|
6
|
Bauer BK, Meier C, Bietenbeck M, Lange PS, Eckardt L, Yilmaz A. Cardiovascular Magnetic Resonance-Guided Radiofrequency Ablation: Where Are We Now? JACC Clin Electrophysiol 2022; 8:261-274. [PMID: 35210090 DOI: 10.1016/j.jacep.2021.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/08/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022]
Abstract
The possibilities of cardiovascular magnetic resonance (CMR) imaging for myocardial tissue characterization and catheter ablation guidance are accompanied by some fictional concepts. In this review, we present the available facts about CMR-guided catheter ablation procedures as well as promising, however unproven, theoretical concepts. CMR promises to visualize the respective arrhythmogenic substrate and may thereby make it more localizable for electrophysiology (EP)-based ablation. Robust CMR imaging is challenged by motion of the heart resulting from cardiac and respiratory cycles. In contrast to conventional "passive" tracking of the catheter tip by real-time CMR, novel approaches based on "active" tracking are performed by integrating microcoils into the catheter tip that send a receiver signal. Several experimental and clinical studies were already performed based on real-time CMR for catheter ablation of atrial and ventricular arrhythmias. Importantly, successful ablation of the cavotricuspid isthmus was already performed in patients with typical atrial flutter. However, a complete EP procedure with real-time CMR-guided transseptal puncture and subsequent pulmonary vein isolation has not been shown so far in patients with atrial fibrillation. Moreover, real-time CMR-guided EP for ventricular tachycardia ablation was only performed in animal models using a transseptal, retrograde, or epicardial access-but not in humans. Essential improvements within the next few years regarding basic technical requirements, such as higher spatial and temporal resolution of real-time CMR imaging as well as clinically approved cardiac magnetic resonance-conditional defibrillators, are ultimately required-but can also be expected-and will move this field forward.
Collapse
Affiliation(s)
- Bastian Klemens Bauer
- Department of Cardiology II - Electrophysiology, University Hospital Münster, Münster, Germany
| | - Claudia Meier
- Department of Cardiology, Division of Cardiovascular Imaging, University Hospital Münster, Münster, Germany
| | - Michael Bietenbeck
- Department of Cardiology, Division of Cardiovascular Imaging, University Hospital Münster, Münster, Germany
| | - Philipp Sebastian Lange
- Department of Cardiology II - Electrophysiology, University Hospital Münster, Münster, Germany
| | - Lars Eckardt
- Department of Cardiology II - Electrophysiology, University Hospital Münster, Münster, Germany
| | - Ali Yilmaz
- Department of Cardiology, Division of Cardiovascular Imaging, University Hospital Münster, Münster, Germany.
| |
Collapse
|
7
|
Cronin IF, Kanter JP, Deutsch N, Hamann K, Olivieri L, Cross RR. Magnetic Resonance Imaging-Guided Cardiac Catheterization Evacuation Drills. Crit Care Nurse 2021; 41:e19-e26. [PMID: 34061187 PMCID: PMC8345020 DOI: 10.4037/ccn2021229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND The interventional cardiac magnetic resonance imaging suite combines a cardiac catheterization x-ray laboratory with a magnetic resonance imaging suite. At the study institution, interventional cardiac magnetic resonance imaging procedures (ie, magnetic resonance imaging-guided cardiac catheterizations) have been performed under institutional review board-approved research protocols since 2015. Because the workplace incorporates x-ray and magnetic resonance imaging in a highly technical environment, education about the importance of magnet safety is crucial to ensure the safety of patients and staff. OBJECTIVE To promote magnetic resonance imaging safety and staff preparedness to respond in emergency situations in a specialized interventional cardiac magnetic resonance imaging environment. METHODS Quarterly in situ evacuation drills with a live volunteer were implemented. A retrospective participant survey using a Likert scale was conducted. Evacuations were timed from the cardiac arrest code alert to safe evacuation or defibrillation if appropriate. RESULTS Over 4 years, 14 drills were performed. Twenty-nine of 48 participants responded to the survey, a 60% response rate. Most participants agreed or strongly agreed that the drills were a positive experience (90%) and that the drills increased their confidence in their ability to perform in an evacuation scenario (100%). Room evacuation times improved from 71 to 41 seconds. No patient or staff safety events occurred in the interventional cardiac magnetic resonance imaging environment. CONCLUSION Magnetic resonance imaging-guided cardiac catheterization evacuation drills promote preparedness, ensure patient and staff safety, and improve evacuation time in the interventional cardiac magnetic resonance imaging environment.
Collapse
Affiliation(s)
- Ileen F Cronin
- Ileen F. Cronin is a nurse practitioner, pediatric cardiac anesthesia, Department of Anesthesiology, Perioperative and Pain Medicine, Lucile Packard Children's Hospital Stanford, Palo Alto, California
| | - Joshua P Kanter
- Joshua P. Kanter is an associate professor of pediatrics, George Washington University School of Medicine, Washington, District of Columbia, and Director of the cardiac catheterization laboratory and an interventional cardiologist, Division of Cardiology, Children's National Hospital, Washington, District of Columbia
| | - Nina Deutsch
- Nina Deutsch is an associate professor of anesthesiology and pediatrics, George Washington University School of Medicine, and Director of cardiac anesthesiology, Division of Cardiology, Children's National Hospital
| | - Karin Hamann
- Karin Hamann is a clinical research nurse program manager, interventional cardiac magnetic resonance program, Division of Cardiology, Children's National Hospital
| | - Laura Olivieri
- Laura Olivieri is an associate professor of pediatrics, George Washington University School of Medicine, and Director of cardiac MRI/CT and an advanced imaging cardiologist, Division of Cardiology, Children's National Hospital
| | - Russell R Cross
- Russell R. Cross is an associate professor of pediatrics, George Washington University School of Medicine, and Medical Director of inpatient cardiology and an advanced imaging cardiologist, Division of Cardiology, Children's National Hospital
| |
Collapse
|
8
|
Abstract
In recent years, interventional cardiac magnetic resonance imaging (iCMR) has evolved from attractive theory to clinical routine at several centers. Real-time cardiac magnetic resonance imaging (CMR fluoroscopy) adds value by combining soft-tissue visualization, concurrent hemodynamic measurement, and freedom from radiation. Clinical iCMR applications are expanding because of advances in catheter devices and imaging. In the near future, iCMR promises novel procedures otherwise unsafe under standalone X-Ray guidance.
Collapse
|
9
|
Mukherjee RK, Costa CM, Neji R, Harrison JL, Sim I, Williams SE, Whitaker J, Chubb H, O'Neill L, Schneider R, Lloyd T, Pohl T, Roujol S, Niederer SA, Razavi R, O'Neill MD. Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment. Europace 2019; 21:1432-1441. [PMID: 31219547 PMCID: PMC6735875 DOI: 10.1093/europace/euz165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/22/2019] [Indexed: 11/21/2022] Open
Abstract
Aims Potential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia–reperfusion model. Methods and results Sites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen–Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30–186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5–1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively. Conclusion Low-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.
Collapse
Affiliation(s)
- Rahul K Mukherjee
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Caroline Mendonca Costa
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK.,Siemens Healthcare, Sir William Siemens Square, Frimley, Camberley, UK
| | - James L Harrison
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK.,Department of Cardiology, King's College Hospital NHS Foundation Trust, London, UK
| | - Iain Sim
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Steven E Williams
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK.,Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Henry Chubb
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Louisa O'Neill
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | | | - Tom Lloyd
- Imricor Medical Systems, 400 Gateway Blvd, MN, USA
| | | | - Sébastien Roujol
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK
| | - Mark D O'Neill
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London, UK.,Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK
| |
Collapse
|
10
|
Shusterman V, Hodgson-Zingman D, Thedens D, Zhu X, Hoffman S, Sieren JC, Morgan GM, Faranesh A, London B. High-energy external defibrillation and transcutaneous pacing during MRI: feasibility and safety. J Cardiovasc Magn Reson 2019; 21:47. [PMID: 31378203 PMCID: PMC6681494 DOI: 10.1186/s12968-019-0558-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/01/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rapid application of external defibrillation, a crucial first-line therapy for ventricular fibrillation and cardiac arrest, is currently unavailable in the setting of magnetic resonance imaging (MRI), raising concerns about patient safety during MRI tests and MRI-guided procedures, particularly in patients with cardiovascular diseases. The objective of this study was to examine the feasibility and safety of defibrillation/pacing for the entire range of clinically useful shock energies inside the MRI bore and during scans, using defibrillation/pacing outside the magnet as a control. METHODS Experiments were conducted using a commercial defibrillator (LIFEPAK 20, Physio-Control, Redmond, Washington, USA) with a custom high-voltage, twisted-pair cable with two mounted resonant floating radiofrequency traps to reduce emission from the defibrillator and the MRI scanner. A total of 18 high-energy (200-360 J) defibrillation experiments were conducted in six swine on a 1.5 T MRI scanner outside the magnet bore, inside the bore, and during scanning, using adult and pediatric defibrillation pads. Defibrillation was followed by cardiac pacing (with capture) in a subset of two animals. Monitored signals included: high-fidelity temperature (0.01 °C, 10 samples/sec) under the pads and 12-lead electrocardiogram (ECG) using an MRI-compatible ECG system. RESULTS Defibrillation/pacing was successful in all experiments. Temperature was higher during defibrillation inside the bore and during scanning compared with outside the bore, but the differences were small (ΔT: 0.5 and 0.7 °C, p = 0.01 and 0.04, respectively). During scans, temperature after defibrillation tended to be higher for pediatric vs. adult pads (p = 0.08). MR-image quality (signal-to-noise ratio) decreased by ~ 10% when the defibrillator was turned on. CONCLUSIONS Our study demonstrates the feasibility and safety of in-bore defibrillation for the full range of defibrillation energies used in clinical practice, as well as of transcutaneous cardiac pacing inside the MRI bore. Methods for Improving MR-image quality in the presence of a working defibrillator require further study.
Collapse
Affiliation(s)
- Vladimir Shusterman
- PinMed, Inc., Pittsburgh, PA USA
- Department of Internal Medicine, The University of Iowa, Iowa City, IA USA
| | | | - Daniel Thedens
- Department of Radiology, The University of Iowa, Iowa City, IA USA
| | - Xiaodong Zhu
- Department of Internal Medicine, The University of Iowa, Iowa City, IA USA
- Department of Biological Sciences, The University of Pittsburgh, Pittsburgh, PA USA
| | | | | | - Gina M. Morgan
- Department of Internal Medicine, The University of Iowa, Iowa City, IA USA
| | | | - Barry London
- Department of Internal Medicine, The University of Iowa, Iowa City, IA USA
| |
Collapse
|
11
|
Mukherjee RK, Whitaker J, Williams SE, Razavi R, O'Neill MD. Magnetic resonance imaging guidance for the optimization of ventricular tachycardia ablation. Europace 2019; 20:1721-1732. [PMID: 29584897 PMCID: PMC6212773 DOI: 10.1093/europace/euy040] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/19/2018] [Indexed: 01/02/2023] Open
Abstract
Catheter ablation has an important role in the management of patients with ventricular tachycardia (VT) but is limited by modest long-term success rates. Magnetic resonance imaging (MRI) can provide valuable anatomic and functional information as well as potentially improve identification of target sites for ablation. A major limitation of current MRI protocols is the spatial resolution required to identify the areas of tissue responsible for VT but recent developments have led to new strategies which may improve substrate assessment. Potential ways in which detailed information gained from MRI may be utilized during electrophysiology procedures include image integration or performing a procedure under real-time MRI guidance. Image integration allows pre-procedural magnetic resonance (MR) images to be registered with electroanatomical maps to help guide VT ablation and has shown promise in preliminary studies. However, multiple errors can arise during this process due to the registration technique used, changes in ventricular geometry between the time of MRI and the ablation procedure, respiratory and cardiac motion. As isthmus sites may only be a few millimetres wide, reducing these errors may be critical to improve outcomes in VT ablation. Real-time MR-guided intervention has emerged as an alternative solution to address the limitations of pre-acquired imaging to guide ablation. There is now a growing body of literature describing the feasibility, techniques, and potential applications of real-time MR-guided electrophysiology. We review whether real-time MR-guided intervention could be applied in the setting of VT ablation and the potential challenges that need to be overcome.
Collapse
Affiliation(s)
- Rahul K Mukherjee
- School of Biomedical Engineering and Imaging Sciences, 4th Floor, North Wing, St Thomas' Hospital, King's College London, London, UK
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, 4th Floor, North Wing, St Thomas' Hospital, King's College London, London, UK
| | - Steven E Williams
- School of Biomedical Engineering and Imaging Sciences, 4th Floor, North Wing, St Thomas' Hospital, King's College London, London, UK.,Department of Cardiology, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, 4th Floor, North Wing, St Thomas' Hospital, King's College London, London, UK
| | - Mark D O'Neill
- School of Biomedical Engineering and Imaging Sciences, 4th Floor, North Wing, St Thomas' Hospital, King's College London, London, UK.,Department of Cardiology, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| |
Collapse
|
12
|
Mukherjee RK, Chubb H, Roujol S, Razavi R, O'Neill MD. Advances in Real-Time MRI-Guided Electrophysiology. CURRENT CARDIOVASCULAR IMAGING REPORTS 2019; 12:6. [PMID: 31501689 PMCID: PMC6733706 DOI: 10.1007/s12410-019-9481-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Purpose of Review Theoretical benefits of real-time MRI guidance over conventional electrophysiology include contemporaneous 3D substrate assessment and accurate intra-procedural guidance and evaluation of ablation lesions. We review the unique challenges inherent to MRI-guided electrophysiology and how to translate the potential benefits in the treatment of cardiac arrhythmias. Recent Findings Over the last 5 years, there has been substantial progress, initially in animal models and more recently in clinical studies, to establish methods and develop workflows within the MR environment that resemble those of conventional electrophysiology laboratories. Real-time MRI-guided systems have been used to perform electroanatomic mapping and ablation in patients with atrial flutter, and there is interest in developing the technology to tackle more complex arrhythmias including atrial fibrillation and ventricular tachycardia. Summary Mainstream adoption of real-time MRI-guided electrophysiology will require demonstration of clinical benefit and will be aided by increased availability of devices suitable for use in the MRI environment.
Collapse
Affiliation(s)
- Rahul K Mukherjee
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London SE1 7EH, UK
| | - Henry Chubb
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London SE1 7EH, UK
| | - Sébastien Roujol
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London SE1 7EH, UK
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London SE1 7EH, UK
| | - Mark D O'Neill
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor, North Wing, St Thomas' Hospital, London SE1 7EH, UK.,Department of Cardiology, King's College Hospital NHS Foundation Trust, London, UK
| |
Collapse
|
13
|
Abstract
Diagnostic and interventional cardiac catheterization is routinely used in the diagnosis and treatment of congenital heart disease. There are well-established concerns regarding the risk of radiation exposure to patients and staff, particularly in children given the cumulative effects of repeat exposure. Magnetic resonance imaging (MRI) offers the advantage of being able to provide better soft tissue visualization, tissue characterization, and quantification of ventricular volumes and vascular flow. Initial work using MRI catheterization employed fusion of x-ray and MRI techniques, with x-ray fluoroscopy to guide catheter placement and subsequent MRI assessment for anatomical and hemodynamic assessment. Image overlay of 3D previously acquired MRI datasets with live fluoroscopic imaging has also been used to guide catheter procedures.Hybrid x-ray and MRI-guided catheterization paved the way for clinical application and validation of this technique in the assessment of pulmonary vascular resistance and pharmacological stress studies. Purely MRI-guided catheterization also proved possible with passive catheter tracking. First-in-man MRI-guided cardiac catheter interventions were possible due to the development of MRI-compatible guidewires, but halted due to guidewire limitations.More recent developments in passive and active catheter tracking have led to improved visualization of catheters for MRI-guided catheterization. Improvements in hardware and software have also increased image quality and scanning times with better interactive tools for the operator in the MRI catheter suite to navigate through the anatomy as required in real time. This has expanded to MRI-guided electrophysiology studies and radiofrequency ablation in humans. Animal studies show promise for the utility of MRI-guided interventional catheterization. Ongoing investment and development of MRI-compatible guidewires will pave the way for MRI-guided diagnostic and interventional catheterization coming into the mainstream.
Collapse
|
14
|
Campbell-Washburn AE, Rogers T, Stine AM, Khan JM, Ramasawmy R, Schenke WH, McGuirt DR, Mazal JR, Grant LP, Grant EK, Herzka DA, Lederman RJ. Right heart catheterization using metallic guidewires and low SAR cardiovascular magnetic resonance fluoroscopy at 1.5 Tesla: first in human experience. J Cardiovasc Magn Reson 2018; 20:41. [PMID: 29925397 PMCID: PMC6011242 DOI: 10.1186/s12968-018-0458-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/10/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) fluoroscopy allows for simultaneous measurement of cardiac function, flow and chamber pressure during diagnostic heart catheterization. To date, commercial metallic guidewires were considered contraindicated during CMR fluoroscopy due to concerns over radiofrequency (RF)-induced heating. The inability to use metallic guidewires hampers catheter navigation in patients with challenging anatomy. Here we use low specific absorption rate (SAR) imaging from gradient echo spiral acquisitions and a commercial nitinol guidewire for CMR fluoroscopy right heart catheterization in patients. METHODS The low-SAR imaging protocol used a reduced flip angle gradient echo acquisition (10° vs 45°) and a longer repetition time (TR) spiral readout (10 ms vs 2.98 ms). Temperature was measured in vitro in the ASTM 2182 gel phantom and post-mortem animal experiments to ensure freedom from heating with the selected guidewire (150 cm × 0.035″ angled-tip nitinol Terumo Glidewire). Seven patients underwent CMR fluoroscopy catheterization. Time to enter each chamber (superior vena cava, main pulmonary artery, and each branch pulmonary artery) was recorded and device visibility and confidence in catheter and guidewire position were scored on a Likert-type scale. RESULTS Negligible heating (< 0.07°C) was observed under all in vitro conditions using this guidewire and imaging approach. In patients, chamber entry was successful in 100% of attempts with a guidewire compared to 94% without a guidewire, with failures to reach the branch pulmonary arteries. Time-to-enter each chamber was similar (p=NS) for the two approaches. The guidewire imparted useful catheter shaft conspicuity and enabled interactive modification of catheter shaft stiffness, however, the guidewire tip visibility was poor. CONCLUSIONS Under specific conditions, trained operators can apply low-SAR imaging and using a specific fully-insulated metallic nitinol guidewire (150 cm × 0.035" Terumo Glidewire) to augment clinical CMR fluoroscopy right heart catheterization. TRIAL REGISTRATION Clinicaltrials.gov NCT03152773 , registered May 15, 2017.
Collapse
Affiliation(s)
- Adrienne E. Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Toby Rogers
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Annette M. Stine
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Jaffar M. Khan
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Rajiv Ramasawmy
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - William H. Schenke
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Delaney R. McGuirt
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Jonathan R. Mazal
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Laurie P. Grant
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Elena K. Grant
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Daniel A. Herzka
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| | - Robert J. Lederman
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10, Room 2C713, Bethesda, MD 20892-1538 USA
| |
Collapse
|
15
|
Berruezo A, Paetsch I. Inception: implanting the idea of magnetic resonance imaging-guided ventricular tachycardia substrate ablation. Europace 2017; 20:f143-f145. [DOI: 10.1093/europace/eux367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Antonio Berruezo
- Arrhythmia Section, Cardiology Department, Institut Clínic Cardiovascular, Hospital Clínic, Universitat de Barcelona, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C/Villarroel 170, Barcelona, Spain
| | - Ingo Paetsch
- Department of Electrophysiology, HELIOS Heart Center Leipzig, University of Leipzig, Struempellstr. 39, Leipzig, Germany
- Department of Cardiology, HELIOS Heart Center Leipzig, University of Leipzig, Struempellstr. 39, Leipzig, Germany
| |
Collapse
|
16
|
Campbell-Washburn AE, Tavallaei MA, Pop M, Grant EK, Chubb H, Rhode K, Wright GA. Real-time MRI guidance of cardiac interventions. J Magn Reson Imaging 2017; 46:935-950. [PMID: 28493526 PMCID: PMC5675556 DOI: 10.1002/jmri.25749] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/29/2017] [Indexed: 11/09/2022] Open
Abstract
Cardiac magnetic resonance imaging (MRI) is appealing to guide complex cardiac procedures because it is ionizing radiation-free and offers flexible soft-tissue contrast. Interventional cardiac MR promises to improve existing procedures and enable new ones for complex arrhythmias, as well as congenital and structural heart disease. Guiding invasive procedures demands faster image acquisition, reconstruction and analysis, as well as intuitive intraprocedural display of imaging data. Standard cardiac MR techniques such as 3D anatomical imaging, cardiac function and flow, parameter mapping, and late-gadolinium enhancement can be used to gather valuable clinical data at various procedural stages. Rapid intraprocedural image analysis can extract and highlight critical information about interventional targets and outcomes. In some cases, real-time interactive imaging is used to provide a continuous stream of images displayed to interventionalists for dynamic device navigation. Alternatively, devices are navigated relative to a roadmap of major cardiac structures generated through fast segmentation and registration. Interventional devices can be visualized and tracked throughout a procedure with specialized imaging methods. In a clinical setting, advanced imaging must be integrated with other clinical tools and patient data. In order to perform these complex procedures, interventional cardiac MR relies on customized equipment, such as interactive imaging environments, in-room image display, audio communication, hemodynamic monitoring and recording systems, and electroanatomical mapping and ablation systems. Operating in this sophisticated environment requires coordination and planning. This review provides an overview of the imaging technology used in MRI-guided cardiac interventions. Specifically, this review outlines clinical targets, standard image acquisition and analysis tools, and the integration of these tools into clinical workflow. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2017;46:935-950.
Collapse
Affiliation(s)
- Adrienne E Campbell-Washburn
- Laboratory of Imaging Technology, Biochemistry and Biophysics Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Mohammad A Tavallaei
- Physical Sciences Platform and Schulich Heart Program, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Mihaela Pop
- Physical Sciences Platform and Schulich Heart Program, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Elena K Grant
- Laboratory of Imaging Technology, Biochemistry and Biophysics Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
- Department of Cardiology, Children's National Medical Center, Washington, DC, USA
| | - Henry Chubb
- Division of Imaging Sciences and Biomedical Engineering, King's College London, UK
| | - Kawal Rhode
- Division of Imaging Sciences and Biomedical Engineering, King's College London, UK
| | - Graham A Wright
- Physical Sciences Platform and Schulich Heart Program, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
17
|
Chubb H, Williams SE, Whitaker J, Harrison JL, Razavi R, O'Neill M. Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology. Arrhythm Electrophysiol Rev 2017; 6:85-93. [PMID: 28845235 DOI: 10.15420/aer.2017.1.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
MR-guidance of electrophysiological (EP) procedures offers the potential for enhanced arrhythmia substrate assessment, improved procedural guidance and real-time assessment of ablation lesion formation. Accurate device tracking techniques, using both active and passive methods, have been developed to offer an interface similar to electroanatomic mapping platforms, and MR-compatible EP equipment continues to be developed. Progress to clinical implementation of these technically complex fields has been relatively slow over the last 10 years, but recent developments have led to successful clinical experience. However, further advances, particularly in harnessing the full imaging potential of CMR, are required to realise the mainstream adoption of this powerful guidance modality.
Collapse
Affiliation(s)
| | - Steven E Williams
- King's College London, London, UK.,Guy's and St Thomas' NHS Foundation Trust, London, UK
| | | | - James L Harrison
- King's College London, London, UK.,Guy's and St Thomas' NHS Foundation Trust, London, UK
| | | | - Mark O'Neill
- King's College London, London, UK.,Guy's and St Thomas' NHS Foundation Trust, London, UK
| |
Collapse
|
18
|
El Hajj SC, Gold MR. Magnetic Resonance Imaging-Conditional External Cardiac Defibrillator: Expanding Access and Safety During Magnetic Resonance Imaging. Circ Cardiovasc Imaging 2016; 9:CIRCIMAGING.116.005573. [PMID: 27729367 DOI: 10.1161/circimaging.116.005573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Stephanie C El Hajj
- From the Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston
| | - Michael R Gold
- From the Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston.
| |
Collapse
|