1
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Roth BJ. The magnetocardiogram. BIOPHYSICS REVIEWS 2024; 5:021305. [PMID: 38827563 PMCID: PMC11139488 DOI: 10.1063/5.0201950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 05/06/2024] [Indexed: 06/04/2024]
Abstract
The magnetic field produced by the heart's electrical activity is called the magnetocardiogram (MCG). The first 20 years of MCG research established most of the concepts, instrumentation, and computational algorithms in the field. Additional insights into fundamental mechanisms of biomagnetism were gained by studying isolated hearts or even isolated pieces of cardiac tissue. Much effort has gone into calculating the MCG using computer models, including solving the inverse problem of deducing the bioelectric sources from biomagnetic measurements. Recently, most magnetocardiographic research has focused on clinical applications, driven in part by new technologies to measure weak biomagnetic fields.
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Affiliation(s)
- Bradley J. Roth
- Department of Physics, Oakland University, Rochester, Michigan 48309, USA
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2
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Yuan Z, Lin S, Liu Y, Tang J, Long T, Zhai Y. Gradient phase and amplitude errors in atomic magnetic gradiometers for biomagnetic imaging systems. iScience 2024; 27:109250. [PMID: 38439975 PMCID: PMC10910274 DOI: 10.1016/j.isci.2024.109250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/30/2024] [Accepted: 02/13/2024] [Indexed: 03/06/2024] Open
Abstract
The cross-axis projection error (CAPE) caused by residual magnetic fields has recently attracted widespread attention. In this study, we propose a more specific theoretical model and expand the CAPE in gradient measurements. We first report that differences in relaxation rate and residual magnetic field between optically pumped magnetometers (OPMs) introduce a significant error term in the output of OPM gradiometers, referred to as the gradient phase error. Furthermore, when the longitudinal field compensation is inadequate, the interaxial response interference of a single OPM is prominent, resulting in an amplitude distortion of the signal. This is further amplified in the gradiometer configuration, introducing the gradient amplitude error. Our experiments demonstrated that the efficacy of mitigating common-mode noise of OPM gradiometers was significantly impaired when existing the gradient errors. In addition, a simulation with a magnetoencephalography (MEG) system illustrated an induced source localization error of exceeding 2 cm, severely compromising the localization accuracy of OPM-MEG systems.
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Affiliation(s)
- Ziqi Yuan
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
| | - Shudong Lin
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
| | - Ying Liu
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Hefei National Laboratory, Hefei 230088, China
| | - Junjian Tang
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- School of Physics, Beihang University, Beijing 100191, China
| | - Tengyue Long
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
| | - Yueyang Zhai
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Hefei National Laboratory, Hefei 230088, China
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Yang Y, Wang H, Liu Z, Wang Y, Han X, Jia Y, Pang J, Xie F, Yu D, Zhang Y, Xiang M, Ning X. Co-registration of OPM-MCG signals with CT using optical scanning. iScience 2023; 26:108235. [PMID: 37942013 PMCID: PMC10628747 DOI: 10.1016/j.isci.2023.108235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/28/2023] [Accepted: 10/13/2023] [Indexed: 11/10/2023] Open
Abstract
Magnetocardiography (MCG) can be used to noninvasively measure the electrophysiological activity of myocardial cells. The high spatial resolution of magnetic source localization can precisely determine the location of cardiomyopathy, which is of great significance for the diagnosis and treatment of cardiovascular disease. To perform magnetic source localization, MCG data must be co-registered with anatomical images. We propose a co-registration method that can be applied to OPM-MCG systems. In this method, the sensor array and the trunk of the subject are scanned using structured light-scanning technology, and the scan results are registered with the reconstructed structure using computed tomography (CT). This can increase the number of effective cloud points acquired and reduce the interference from respiratory motion. The scanning bed of the OPM-MCG system was modified to be consistent with the CT device, ensuring that the state of the body remains consistent between the cardiac magnetometry measurements and CT scans.
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Affiliation(s)
- Yanfei Yang
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
| | - Huidong Wang
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
| | - Zhanyi Liu
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
| | - Yanmei Wang
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
| | - Xiaole Han
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
| | - Yifan Jia
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
| | - Jiaojiao Pang
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
- Department of Emergency Medicine, Qilu Hospital of Shandong University, Shandong Provincial Clinical Research Center for Emergency and Critical Care Medicine, Jinan 250014, China
- National Innovation Platform for Industry-Education Intearation in Medicine-Engineering Interdisciplinary, Shandong University, Jinan 250014, China
| | - Fei Xie
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
- Department of Emergency Medicine, Qilu Hospital of Shandong University, Shandong Provincial Clinical Research Center for Emergency and Critical Care Medicine, Jinan 250014, China
- National Innovation Platform for Industry-Education Intearation in Medicine-Engineering Interdisciplinary, Shandong University, Jinan 250014, China
| | - Dexin Yu
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
- National Innovation Platform for Industry-Education Intearation in Medicine-Engineering Interdisciplinary, Shandong University, Jinan 250014, China
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250014, China
| | - Yang Zhang
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
- National Innovation Platform for Industry-Education Intearation in Medicine-Engineering Interdisciplinary, Shandong University, Jinan 250014, China
- Department of Radiology, Qilu Hospital of Shandong University, Jinan 250014, China
| | - Min Xiang
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
- Hangzhou Institute of National Extremely-weak Magnetic Field Infrastructure, Hangzhou 310028, China
- Hefei National Laboratory, Hefei 230088, China
- State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangzhou 510006, China
| | - Xiaolin Ning
- Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
- Zhejiang Provincial Key Laboratory of Ultra-Weak Magnetic-Field Space and Applied Technology, Hangzhou Innovation Institute, Beihang University, Hangzhou 310051, China
- Shandong Key Laboratory for Magnetic Field-free Medicine & Functional Imaging, Institute of Magnetic Field-free Medicine & Functional Imaging, Shandong University, Jinan 250014, China
- Hangzhou Institute of National Extremely-weak Magnetic Field Infrastructure, Hangzhou 310028, China
- Hefei National Laboratory, Hefei 230088, China
- State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangzhou 510006, China
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Wang Y, Zhao ZG, Chai Z, Fang JC, Chen M. Electromagnetic field and cardiovascular diseases: A state-of-the-art review of diagnostic, therapeutic, and predictive values. FASEB J 2023; 37:e23142. [PMID: 37650634 DOI: 10.1096/fj.202300201rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 07/20/2023] [Accepted: 08/02/2023] [Indexed: 09/01/2023]
Abstract
Despite encouraging advances in early diagnosis and treatment, cardiovascular diseases (CVDs) remained a leading cause of morbidity and mortality worldwide. Increasing evidence has shown that the electromagnetic field (EMF) influences many biological processes, which has attracted much attention for its potential therapeutic and diagnostic modalities in multiple diseases, such as musculoskeletal disorders and neurodegenerative diseases. Nonionizing EMF has been studied as a therapeutic or diagnostic tool in CVDs. In this review, we summarize the current literature ranging from in vitro to clinical studies focusing on the therapeutic potential (external EMF) and diagnostic potential (internal EMF generated from the heart) of EMF in CVDs. First, we provided an overview of the therapeutic potential of EMF and associated mechanisms in the context of CVDs, including cardiac arrhythmia, myocardial ischemia, atherosclerosis, and hypertension. Furthermore, we investigated the diagnostic and predictive value of magnetocardiography in CVDs. Finally, we discussed the critical steps necessary to translate this promising approach into clinical practice.
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Affiliation(s)
- Yan Wang
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zhen-Gang Zhao
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Zheng Chai
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jian-Cheng Fang
- School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing, China
| | - Mao Chen
- Laboratory of Heart Valve Disease, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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5
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Brisinda D, Fenici P, Fenici R. Clinical magnetocardiography: the unshielded bet-past, present, and future. Front Cardiovasc Med 2023; 10:1232882. [PMID: 37636301 PMCID: PMC10448194 DOI: 10.3389/fcvm.2023.1232882] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/23/2023] [Indexed: 08/29/2023] Open
Abstract
Magnetocardiography (MCG), which is nowadays 60 years old, has not yet been fully accepted as a clinical tool. Nevertheless, a large body of research and several clinical trials have demonstrated its reliability in providing additional diagnostic electrophysiological information if compared with conventional non-invasive electrocardiographic methods. Since the beginning, one major objective difficulty has been the need to clean the weak cardiac magnetic signals from the much higher environmental noise, especially that of urban and hospital environments. The obvious solution to record the magnetocardiogram in highly performant magnetically shielded rooms has provided the ideal setup for decades of research demonstrating the diagnostic potential of this technology. However, only a few clinical institutions have had the resources to install and run routinely such highly expensive and technically demanding systems. Therefore, increasing attempts have been made to develop cheaper alternatives to improve the magnetic signal-to-noise ratio allowing MCG in unshielded hospital environments. In this article, the most relevant milestones in the MCG's journey are reviewed, addressing the possible reasons beyond the currently long-lasting difficulty to reach a clinical breakthrough and leveraging the authors' personal experience since the early 1980s attempting to finally bring MCG to the patient's bedside for many years thus far. Their nearly four decades of foundational experimental and clinical research between shielded and unshielded solutions are summarized and referenced, following the original vision that MCG had to be intended as an unrivaled method for contactless assessment of the cardiac electrophysiology and as an advanced method for non-invasive electroanatomical imaging, through multimodal integration with other non-fluoroscopic imaging techniques. Whereas all the above accounts for the past, with the available innovative sensors and more affordable active shielding technologies, the present demonstrates that several novel systems have been developed and tested in multicenter clinical trials adopting both shielded and unshielded MCG built-in hospital environments. The future of MCG will mostly be dependent on the results from the ongoing progress in novel sensor technology, which is relatively soon foreseen to provide multiple alternatives for the construction of more compact, affordable, portable, and even wearable devices for unshielded MCG inside hospital environments and perhaps also for ambulatory patients.
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Affiliation(s)
- D. Brisinda
- Dipartimento Scienze dell'invecchiamento, ortopediche e reumatologiche, Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, Italy
- School of Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
- Biomagnetism and Clinical Physiology International Center (BACPIC), Rome, Italy
| | - P. Fenici
- School of Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
- Biomagnetism and Clinical Physiology International Center (BACPIC), Rome, Italy
| | - R. Fenici
- Biomagnetism and Clinical Physiology International Center (BACPIC), Rome, Italy
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6
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Roth BJ. Biomagnetism: The First Sixty Years. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23094218. [PMID: 37177427 PMCID: PMC10181075 DOI: 10.3390/s23094218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/21/2023] [Accepted: 04/22/2023] [Indexed: 05/15/2023]
Abstract
Biomagnetism is the measurement of the weak magnetic fields produced by nerves and muscle. The magnetic field of the heart-the magnetocardiogram (MCG)-is the largest biomagnetic signal generated by the body and was the first measured. Magnetic fields have been detected from isolated tissue, such as a peripheral nerve or cardiac muscle, and these studies have provided insights into the fundamental properties of biomagnetism. The magnetic field of the brain-the magnetoencephalogram (MEG)-has generated much interest and has potential clinical applications to epilepsy, migraine, and psychiatric disorders. The biomagnetic inverse problem, calculating the electrical sources inside the brain from magnetic field recordings made outside the head, is difficult, but several techniques have been introduced to solve it. Traditionally, biomagnetic fields are recorded using superconducting quantum interference device (SQUID) magnetometers, but recently, new sensors have been developed that allow magnetic measurements without the cryogenic technology required for SQUIDs.
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Affiliation(s)
- Bradley J Roth
- Department of Physics, Oakland University, Rochester, MI 48309, USA
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Xiao W, Sun C, Shen L, Feng Y, Liu M, Wu Y, Liu X, Wu T, Peng X, Guo H. A movable unshielded magnetocardiography system. SCIENCE ADVANCES 2023; 9:eadg1746. [PMID: 36989361 PMCID: PMC10058232 DOI: 10.1126/sciadv.adg1746] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/28/2023] [Indexed: 06/19/2023]
Abstract
Magnetocardiography (MCG), which uses high-sensitivity magnetometers to record magnetic field signals generated by electrical activity in the heart, is a noninvasive method for evaluating heart diseases such as arrhythmia and ischemia. The MCG measurements usually require the participant keeping still in a magnetically shielded room due to the immovable sensor and noisy external environments. These requirements limit MCG applications, such as exercise MCG tests and long-term MCG observations, which are useful for early detections of heart diseases. Here, we introduce a movable MCG system that can clearly record MCG signals of freely behaving participants in an unshielded environment. On the basis of optically pumped magnetometers with a sensitivity of 140 fT/Hz1/2, we successfully demonstrated the resting MCG and the exercise MCG tests. Our method is promising to realize a practical movable multichannel unshielded MCG system that nearly sets no limits to participants and brings another kind of insight into the medical diagnosis of heart disease.
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Affiliation(s)
| | | | - Liang Shen
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Yulong Feng
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Meng Liu
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Yulong Wu
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Xiyu Liu
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Teng Wu
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Xiang Peng
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
| | - Hong Guo
- State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China
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Zhao W, Tao X, Ye C, Tao Y. Tunnel Magnetoresistance Sensor with AC Modulation and Impedance Compensation for Ultra-Weak Magnetic Field Measurement. SENSORS 2022; 22:s22031021. [PMID: 35161769 PMCID: PMC8838231 DOI: 10.3390/s22031021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 11/20/2022]
Abstract
Tunnel magnetoresistance (TMR) is a kind of magnetic sensor with the advantages of low cost and high sensitivity. For ultra-weak and low-frequency magnetic field measurement, the TMR sensor is affected by the 1/f noise. This paper proposes an AC modulation method with impedance compensation to improve the performance. The DC and AC characteristics of the sensors were measured and are presented here. It was found that both the equivalent resistance and capacitor of the sensors are affected by the external magnetic field. The TMR sensors are connected as a push–pull bridge circuit to measure the magnetic field. To reduce the common-mode noise, two similar bridge circuits form a magnetic gradiometer. Experimental results show that the sensor’s sensitivity in the low-frequency range is obviously improved by the modulation and impedance compensation. The signal-to-noise ratio of the sensor at 1 Hz was increased about 25.3 dB by the AC modulation, impedance compensation, and gradiometer measurement setup. In addition, the sensitivity of the sensor was improved from 165.2 to 222.1 mV/V/mT. Ultra-weak magnetic signals, namely magnetocardiography signals of two human bodies, were measured by the sensor in an unshielded environment. It was seen that the R peak of MCG can be clearly visualized from the recorded signal.
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Affiliation(s)
- Wenlei Zhao
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China; (W.Z.); (X.T.); (C.Y.)
| | - Xinchen Tao
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China; (W.Z.); (X.T.); (C.Y.)
| | - Chaofeng Ye
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China; (W.Z.); (X.T.); (C.Y.)
- China Shanghai Engineering Research Center of Energy Efficient and Custom AI IC, Shanghai 201210, China
| | - Yu Tao
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China; (W.Z.); (X.T.); (C.Y.)
- Correspondence:
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Spetzler B, Wiegand P, Durdaut P, Höft M, Bahr A, Rieger R, Faupel F. Modeling and Parallel Operation of Exchange-Biased Delta-E Effect Magnetometers for Sensor Arrays. SENSORS (BASEL, SWITZERLAND) 2021; 21:7594. [PMID: 34833678 PMCID: PMC8619412 DOI: 10.3390/s21227594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/10/2021] [Accepted: 11/14/2021] [Indexed: 02/02/2023]
Abstract
Recently, Delta-E effect magnetic field sensors based on exchange-biased magnetic multilayers have shown the potential of detecting low-frequency and small-amplitude magnetic fields. Their design is compatible with microelectromechanical system technology, potentially small, and therefore, suitable for arrays with a large number N of sensor elements. In this study, we explore the prospects and limitations for improving the detection limit by averaging the output of N sensor elements operated in parallel with a single oscillator and a single amplifier to avoid additional electronics and keep the setup compact. Measurements are performed on a two-element array of exchange-biased sensor elements to validate a signal and noise model. With the model, we estimate requirements and tolerances for sensor elements using larger N. It is found that the intrinsic noise of the sensor elements can be considered uncorrelated, and the signal amplitude is improved if the resonance frequencies differ by less than approximately half the bandwidth of the resonators. Under these conditions, the averaging results in a maximum improvement in the detection limit by a factor of N. A maximum N≈200 exists, which depends on the read-out electronics and the sensor intrinsic noise. Overall, the results indicate that significant improvement in the limit of detection is possible, and a model is presented for optimizing the design of delta-E effect sensor arrays in the future.
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Affiliation(s)
- Benjamin Spetzler
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
| | - Patrick Wiegand
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
| | - Phillip Durdaut
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
| | - Michael Höft
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
| | - Andreas Bahr
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
| | - Robert Rieger
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
| | - Franz Faupel
- Institute of Materials Science, Faculty of Engineering, Kiel University, 24143 Kiel, Germany
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10
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Teaching Magnetoelectric Sensing to Secondary School Students-Considerations for Educational STEM Outreach. SENSORS 2021; 21:s21217354. [PMID: 34770664 PMCID: PMC8588487 DOI: 10.3390/s21217354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/01/2021] [Accepted: 11/02/2021] [Indexed: 11/17/2022]
Abstract
A major challenge in modern society is the need to increase awareness and excitement with regard to science, technology, engineering and mathematics (STEM) and related careers directly or among peers and parents in order to attract future generations of scientists and engineers. The numbers of students aiming for an engineering degree are low compared to the options available and the workforce needed. This may, in part, be due to a traditional lack of instruction in this area in secondary school curricula. In this regard, STEM outreach programs can complement formal learning settings and help to promote engineering as well as science to school students. In a long-term outreach collaboration with scientists and engineers, we developed an outreach program in the field of magnetoelectric sensing that includes an out-of-school project day and various accompanying teaching materials. In this article, we motivate the relevance of the topic for educational outreach, share the rationales, objectives and aims, models and implementation strategies of our program and provide practical advice for those interested in outreach in the field of magnetoelectric sensing.
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11
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Spetzler B, Golubeva EV, Friedrich RM, Zabel S, Kirchhof C, Meyners D, McCord J, Faupel F. Magnetoelastic Coupling and Delta-E Effect in Magnetoelectric Torsion Mode Resonators. SENSORS 2021; 21:s21062022. [PMID: 33809318 PMCID: PMC7999320 DOI: 10.3390/s21062022] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023]
Abstract
Magnetoelectric resonators have been studied for the detection of small amplitude and low frequency magnetic fields via the delta-E effect, mainly in fundamental bending or bulk resonance modes. Here, we present an experimental and theoretical investigation of magnetoelectric thin-film cantilevers that can be operated in bending modes (BMs) and torsion modes (TMs) as a magnetic field sensor. A magnetoelastic macrospin model is combined with an electromechanical finite element model and a general description of the delta-E effect of all stiffness tensor components Cij is derived. Simulations confirm quantitatively that the delta-E effect of the C66 component has the promising potential of significantly increasing the magnetic sensitivity and the maximum normalized frequency change Δfr. However, the electrical excitation of TMs remains challenging and is found to significantly diminish the gain in sensitivity. Experiments reveal the dependency of the sensitivity and Δfr of TMs on the mode number, which differs fundamentally from BMs and is well explained by our model. Because the contribution of C11 to the TMs increases with the mode number, the first-order TM yields the highest magnetic sensitivity. Overall, general insights are gained for the design of high-sensitivity delta-E effect sensors, as well as for frequency tunable devices based on the delta-E effect.
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12
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Yang Y, Xu M, Liang A, Yin Y, Ma X, Gao Y, Ning X. A new wearable multichannel magnetocardiogram system with a SERF atomic magnetometer array. Sci Rep 2021; 11:5564. [PMID: 33692397 PMCID: PMC7970947 DOI: 10.1038/s41598-021-84971-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 02/23/2021] [Indexed: 11/30/2022] Open
Abstract
In this study, a wearable multichannel human magnetocardiogram (MCG) system based on a spin exchange relaxation-free regime (SERF) magnetometer array is developed. The MCG system consists of a magnetically shielded device, a wearable SERF magnetometer array, and a computer for data acquisition and processing. Multichannel MCG signals from a healthy human are successfully recorded simultaneously. Independent component analysis (ICA) and empirical mode decomposition (EMD) are used to denoise MCG data. MCG imaging is realized to visualize the magnetic and current distribution around the heart. The validity of the MCG signals detected by the system is verified by electrocardiogram (ECG) signals obtained at the same position, and similar features and intervals of cardiac signal waveform appear on both MCG and ECG. Experiments show that our wearable MCG system is reliable for detecting MCG signals and can provide cardiac electromagnetic activity imaging.
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Affiliation(s)
- Yanfei Yang
- School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing, 100191, China
| | - Mingzhu Xu
- School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing, 100191, China
| | - Aimin Liang
- Department of Child Health Care Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Yan Yin
- School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing, 100191, China
| | - Xin Ma
- Hangzhou Innovation Institute, Beihang University, Hangzhou, 310051, China.,Research Institute for Frontier Science, Beihang University, Beijing, 100191, China
| | - Yang Gao
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.,School of Physics, Beihang University, Beijing, 100191, China
| | - Xiaolin Ning
- Hangzhou Innovation Institute, Beihang University, Hangzhou, 310051, China. .,Research Institute for Frontier Science, Beihang University, Beijing, 100191, China.
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13
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Exchange biased delta-E effect enables the detection of low frequency pT magnetic fields with simultaneous localization. Sci Rep 2021; 11:5269. [PMID: 33674690 PMCID: PMC7936012 DOI: 10.1038/s41598-021-84415-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 01/08/2021] [Indexed: 01/31/2023] Open
Abstract
Delta-E effect sensors are based on magnetoelectric resonators that detune in a magnetic field due to the delta-E effect of the magnetostrictive material. In recent years, such sensors have shown the potential to detect small amplitude and low-frequency magnetic fields. Yet, they all require external magnetic bias fields for optimal operation, which is highly detrimental to their application. Here, we solve this problem by combining the delta-E effect with exchange biased multilayers and operate the resonator in a low-loss torsion mode. It is comprehensively analyzed experimentally and theoretically using various kinds of models. Due to the exchange bias, no external magnetic bias fields are required, but still low detection limits down to [Formula: see text] at 25 Hz are achieved. The potential of this concept is demonstrated with a new operating scheme that permits simultaneous measurement and localization, which is especially desirable for typical biomedical inverse solution problems. The sensor is localized with a minimum spatial resolution of 1 cm while measuring a low-frequency magnetic test signal that can be well reconstructed. Overall, we demonstrate that this class of magnetic field sensors is a significant step towards first biomedical applications and compact large number sensor arrays.
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Abstract
Historically, the activity of muscle groups has been evaluated indirectly, through strength and range of movement measurements. While direct evaluation of muscle activity has been achieved using surface or invasive electrodes, the latter methodologies are limited to individual muscles. By contrast, magnetic recording of muscle activity, as illustrated here, offers a noninvasive approach to evaluate the activity of large muscle groups. This includes deep structures such as the heart and intraabdominal musculature such as the iliacus muscle. An unexpected finding was the ability to image activity associated with muscle pain. Thus, this method offers a noninvasive biomarker for muscular pain and, significantly, of neck and back pain, which now relies mainly on the patient’s report of signs and symptoms. A spectroscopic paradigm has been developed that allows the magnetic field emissions generated by the electrical activity in the human body to be imaged in real time. The growing significance of imaging modalities in biology is evident by the almost exponential increase of their use in research, from the molecular to the ecological level. The method of analysis described here allows totally noninvasive imaging of muscular activity (heart, somatic musculature). Such imaging can be obtained without additional methodological steps such as the use of contrast media.
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15
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Shin ES, Chung JH, Park SG, Saleh A, Lam YY, Bhak J, Jung F, Morita S, Brachmann J. Comparison of exercise electrocardiography and magnetocardiography for detection of coronary artery disease using ST-segment fluctuation score. Clin Hemorheol Microcirc 2019; 73:283-291. [DOI: 10.3233/ch-180485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Eun-Seok Shin
- Department of Cardiology, Ulsan Medical Center, Ulsan Hospital, Ulsan, South Korea
| | - Ju-Hyun Chung
- Department of Cardiology, Ulsan Medical Center, Ulsan Hospital, Ulsan, South Korea
| | - Seung Gu Park
- Korean Genomics Industrialization and Commercialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Ahmed Saleh
- Coburg Hospital, 2nd Medical Department, Coburg, Germany
| | - Yat-Yin Lam
- Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong
| | - Jong Bhak
- Korean Genomics Industrialization and Commercialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Friedrich Jung
- Institute of Biomaterial Science and Berlin-Brandenburg, Center for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany
| | - Sumio Morita
- Department of Cardiology, Charité Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Berlin, Germany
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16
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Bai M, Huang Y, Zhang G, Zheng W, Lin Q, Hu Z. Fast backward singular value decomposition (SVD) algorithm for magnetocardiographic signal reconstruction from pulsed atomic magnetometer data. OPTICS EXPRESS 2019; 27:29534-29546. [PMID: 31684213 DOI: 10.1364/oe.27.029534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
In a pulse pump Rb atomic magnetometer, the magnetic field is associated with the Larmor frequency of the free induction decay (FID) signal. The reconstruction of the magnetic field from the collected signal, thereby, is crucial for magnetocardiography. In this study, we propose a backward singular value decomposition (BSVD) method for fast reconstruction of a magnetocardiographic signal. Experiments on the simulated and real data were performed to estimate its potential advantages over previous approaches, such as the fast Fourier transform (FFT) method, the zero-crossing means (ZM) method, etc. The results show the high accuracy of the BSVD method compared with other methods. More importantly, the BSVD method requires less sampled data than other methods while ensuring the accuracy. With the help of it, the recording time can be greatly reduced from the initial 3.6m s to the present 0.6m s. Thus, the time resolution of the magnetocardiograph could reach 2m s which is equivalent to that of conventional electrocardiogragh. This will bring the atomic magnetocardiography more practicable in clinic application.
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17
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Shin ES, Park SG, Saleh A, Lam YY, Bhak J, Jung F, Morita S, Brachmann J. Magnetocardiography scoring system to predict the presence of obstructive coronary artery disease. Clin Hemorheol Microcirc 2019; 70:365-373. [DOI: 10.3233/ch-189301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Eun-Seok Shin
- Division of Cardiology, Ulsan Medical Center, Ulsan Hospital, Ulsan, Korea
| | - Seung Gu Park
- Korean Genomics Industrialization and Commercialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, Korea
| | - Ahmed Saleh
- 2nd Medical Department, Coburg Hospital, Coburg, Germany
| | - Yat-Yin Lam
- Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong
| | - Jong Bhak
- Korean Genomics Industrialization and Commercialization Center (KOGIC), Ulsan National Institute of Science and Technology (UNIST), Ulsan, Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Korea
| | - Friedrich Jung
- Institute of Biomaterial Science and Berlin-Brandenburg, Center for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany
| | - Sumio Morita
- Department of Cardiology, Charité Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
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Guida G, Sorbo AR, Fenici R, Brisinda D. Predictive value of unshielded magnetocardiographic mapping to differentiate atrial fibrillation patients from healthy subjects. Ann Noninvasive Electrocardiol 2018; 23:e12569. [PMID: 29947446 DOI: 10.1111/anec.12569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/07/2018] [Accepted: 05/23/2018] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND P-wave duration, its dispersion and signal-averaged ECG, are currently used markers of vulnerability to atrial fibrillation (AF). However, since tangential atrial currents are better detectable at the body surface as magnetic than electric signals, we investigated the accuracy of magnetocardiographic mapping (MCG), recorded in unshielded clinical environments, as predictor of AF occurrence. METHODS MCG recordings, in sinus rhythm (SR), of 71 AF patients and 75 controls were retrospectively analyzed. Beside electric and magnetic P-wave and PR interval duration, two MCG P-wave subintervals, defined P-dep and P-rep, were measured, basing on the point of inversion of atrial magnetic field (MF). Eight parameters were calculated from inverse solution with "Effective Magnetic Dipole (EMD) model" and 5 from "MF Extrema" analysis. Discriminant analysis (DA) was used to assess MCG predictive accuracy to differentiate AF patients from controls. RESULTS All but one (P-rep) intervals were significantly longer in AF patients. At univariate analysis, three EMD parameters differed significantly: in AF patients, the dipole-angle-elevation angular speed was lower during P-dep (p < 0.05) and higher during P-rep (p < 0.001) intervals. The space-trajectory during P-rep and the angle-dynamics during P-dep were higher (p < 0.05), whereas ratio-dynamics P-dep was lower (p < 0.01), in AF. At DA, with a combination of MCG and clinical parameters, 81.5% accuracy in differentiating AF patients from controls was achieved. At Cox-regression, the angle-dynamics P-dep was an independent predictor of AF recurrences (p = 0.037). CONCLUSIONS Quantitative analysis of atrial MF dynamics in SR and the solution of the inverse problem provide new sensitive markers of vulnerability to AF.
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Affiliation(s)
- Gianluigi Guida
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Anna Rita Sorbo
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Riccardo Fenici
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Donatella Brisinda
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
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Lombardi G, Sorbo AR, Guida G, La Brocca L, Fenici R, Brisinda D. Magnetocardiographic classification and non-invasive electro-anatomical imaging of outflow tract ventricular arrhythmias in recreational sport activity practitioners. J Electrocardiol 2018; 51:433-439. [DOI: 10.1016/j.jelectrocard.2018.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/25/2018] [Accepted: 02/08/2018] [Indexed: 10/18/2022]
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Mäntynen V, Lehto M, Parikka H, Montonen J. Noninvasive mapping reveals recurrent and suddenly changing patterns in atrial fibrillation-a magnetocardiographic study. Physiol Meas 2018; 39:025006. [PMID: 29271352 DOI: 10.1088/1361-6579/aaa3bb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To study noninvasive magnetocardiographic (MCG) mapping of ongoing atrial fibrillation (AF) and, for the possible mapping patterns observed, to develop simplified but meaningful descriptors or parameters, providing a possible basis for future research and clinical use of the mappings. APPROACH MCG mapping with simultaneous ECG was recorded during arrhythmia in patients representing a range of typical, clinically classical atrial arrhythmias. The recordings were assessed using MCG map animations, and a method to compute magnetic field map orientation (MFO) and its time course was created to facilitate presentation of the findings. All the data were segmented into four categories of ECG waveform regularity. MAIN RESULTS In visual observation of the MCG animations, an abundance of clear spatial and temporal patterns with regularity were found, often perceived as rotations of the map. This rotation and its sudden reversals of direction were distinctly present in the time course of the MFO. The shortest segments with consistent rotation lasted for some hundreds of milliseconds, i.e. a couple of cycles, but segments lasting for tens of seconds were observed as well. In the ECG, all four categories of regularity were present. The rotation of the MFO was observed in all patients under study and regardless of the ECG categories. Further, a change in ECG category during a measurement was frequently, but not always, found to be simultaneous with a change in the rotation pattern of the MFO. Utilization of spatial information of MCG mapping could enable detection of both regularities and instantaneous phenomena during AF. SIGNIFICANCE Cardiac mapping may offer a useful noninvasive means to study the mechanisms of AF, including superior temporal resolution.
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Affiliation(s)
- Ville Mäntynen
- BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, PO Box 340, FI-00029 HUS, Finland. Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland, PO Box 12200, FI-00076 AALTO, Finland
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21
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Sorbo AR, Lombardi G, La Brocca L, Guida G, Fenici R, Brisinda D. Unshielded magnetocardiography: Repeatability and reproducibility of automatically estimated ventricular repolarization parameters in 204 healthy subjects. Ann Noninvasive Electrocardiol 2017; 23:e12526. [PMID: 29266621 DOI: 10.1111/anec.12526] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/07/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Magnetocardiographic mapping (MCG) provides quantitative assessment of the magnetic field (MF) induced by cardiac ionic currents, is more sensitive to tangential currents, and measures vortex currents undetectable by ECG, with higher reported sensitivity of MCG ventricular repolarization (VR) parameters for earlier detection of acute myocardial ischemia. Aims of this study were to validate the feasibility of in-hospital unshielded MCG and to assess repeatability and reproducibility of quantitative VR parameters, considering also possible gender- and age-related variability. METHODS MCG of 204 healthy subjects [114 males-mean age 43.4 ± 17.3 and 90 females-mean age 40.2 ± 15.7] was retrospectively analyzed, with a patented proprietary software automatically estimating twelve VR parameters derived from the analysis of the dynamics of the T-wave MF extrema (five parameters) and from the inverse solution with the effective magnetic dipole model giving the effective magnetic vector components (seven parameters). MCG repeatability was calculated as coefficient of variation (CV) ±standard error of the mean (SEM). Reproducibility was assessed as intraclass correlation coefficient (ICC). RESULTS The repeatability of all MCG parameters was 16 ± 1.2 (%) (average CV ± SEM). Optimal (ICC > 0.7) reproducibility was found for 11/12 parameters (mean values) and in 8/12 parameters (single values). No significant gender-related difference was observed; six parameters showed a strong/moderate correlation with age. CONCLUSION Reliable MCG can be performed into an unshielded hospital ambulatory, with repeatability and reproducibility of quantitative assessment of VR adequate for clinical purposes. Wider clinical use is foreseen with the development of multichannel optical magnetometry.
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Affiliation(s)
- Anna Rita Sorbo
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Gianmarco Lombardi
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Lara La Brocca
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Gianluigi Guida
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Riccardo Fenici
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
| | - Donatella Brisinda
- Biomagnetism and Clinical Physiology International Center, Catholic University of Sacred Heart, Rome, Italy
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22
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Morales S, Corsi MC, Fourcault W, Bertrand F, Cauffet G, Gobbo C, Alcouffe F, Lenouvel F, Le Prado M, Berger F, Vanzetto G, Labyt E. Magnetocardiography measurements with 4He vector optically pumped magnetometers at room temperature. Phys Med Biol 2017; 62:7267-7279. [PMID: 28257003 DOI: 10.1088/1361-6560/aa6459] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this paper, we present a proof of concept study which demonstrates for the first time the possibility of recording magnetocardiography (MCG) signals with 4He vector optically pumped magnetometers (OPM) operated in a gradiometer mode. Resulting from a compromise between sensitivity, size and operability in a clinical environment, the developed magnetometers are based on the parametric resonance of helium in a zero magnetic field. Sensors are operated at room temperature and provide a tri-axis vector measurement of the magnetic field. Measured sensitivity is around 210 f T (√Hz)-1 in the bandwidth (2 Hz; 300 Hz). MCG signals from a phantom and two healthy subjects are successfully recorded. Human MCG data obtained with the OPMs are compared to reference electrocardiogram recordings: similar heart rates, shapes of the main patterns of the cardiac cycle (P/T waves, QRS complex) and QRS widths are obtained with both techniques.
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Affiliation(s)
- S Morales
- CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
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23
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Putaala J, Martinez-Majander N, Saeed S, Yesilot N, Jäkälä P, Nerg O, Tsivgoulis G, Numminen H, Gordin D, von Sarnowski B, Waje-Andreassen U, Ylikotila P, Roine RO, Zedde M, Huhtakangas J, Fonseca C, Redfors P, de Leeuw FE, Pezzini A, Kõrv J, Schneider S, Tanislav C, Enzinger C, Jatuzis D, Siegerink B, Martínez-Sánchez P, Grau AJ, Palm F, Groop PH, Lanthier S, Ten Cate H, Pussinen P, Paju S, Sinisalo J, Lehto M, Lindgren A, Ferro J, Kittner S, Fazekas F, Gerdts E, Tatlisumak T. Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Triggers, Causes, and Outcome (SECRETO): Rationale and design. Eur Stroke J 2017; 2:116-125. [PMID: 31008307 PMCID: PMC6453214 DOI: 10.1177/2396987317703210] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/22/2017] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Worldwide, about 1.3 million annual ischaemic strokes (IS) occur in adults aged <50 years. Of these early-onset strokes, up to 50% can be regarded as cryptogenic or associated with conditions with poorly documented causality like patent foramen ovale and coagulopathies. KEY HYPOTHESES/AIMS (1) Investigate transient triggers and clinical/sub-clinical chronic risk factors associated with cryptogenic IS in the young; (2) use cardiac imaging methods exceeding state-of-the-art to reveal novel sources for embolism; (3) search for covert thrombosis and haemostasis abnormalities; (4) discover new disease pathways using next-generation sequencing and RNA gene expression studies; (5) determine patient prognosis by use of phenotypic and genetic data; and (6) adapt systems medicine approach to investigate complex risk-factor interactions. DESIGN Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) is a prospective multi-centre case-control study enrolling patients aged 18-49 years hospitalised due to first-ever imaging-proven IS of undetermined etiology. Patients are examined according to a standardised protocol and followed up for 10 years. Patients are 1:1 age- and sex-matched to stroke-free controls. Key study elements include centralised reading of echocardiography, electrocardiography, and neurovascular imaging, as well as blood samples for genetic, gene-expression, thrombosis and haemostasis and biomarker analysis. We aim to have 600 patient-control pairs enrolled by the end of 2018. SUMMARY SECRETO is aiming to establish novel mechanisms and prognosis of cryptogenic IS in the young and will provide new directions for therapy development for these patients. First results are anticipated in 2019.
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Affiliation(s)
- Jukka Putaala
- Department of Neurology, Helsinki
University Hospital, Finland
| | | | - Sahrai Saeed
- Department of Clinical Science,
University of Bergen, Norway
| | - Nilufer Yesilot
- Department of Neurology, Istanbul
Faculty of Medicine, Istanbul University, Turkey
| | - Pekka Jäkälä
- Neuro Center, Kuopio University
Hospital, Finland
| | - Ossi Nerg
- Neuro Center, Kuopio University
Hospital, Finland
| | - Georgios Tsivgoulis
- Second Department of Neurology, National
and Kapodistrian University of Athens, Attikon University Hospital, Greece
| | - Heikki Numminen
- Department of Neuroscience and
Rehabilitation, Tampere University Hospital, Finland
| | - Daniel Gordin
- Folkhälsan Institute of Genetics,
Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki,
Finland
| | | | | | - Pauli Ylikotila
- Division of Clinical Neurosciences,
Turku University Hospital, University of Turku, Finland
| | - Risto O Roine
- Division of Clinical Neurosciences,
Turku University Hospital, University of Turku, Finland
| | | | | | - Catarina Fonseca
- Department of Neurosciences
(Neurology), Hospital de Santa Maria, University of Lisbon, Portugal
| | - Petra Redfors
- Department of Clinical Neuroscience,
Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of
Gothenburg, Sweden
- Department of Neurology, Sahlgrenska
University Hospital, Sweden
| | - Frank-Erik de Leeuw
- Department of Neurology, Donders
Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud
University Medical Center, The Netherlands
| | - Alessandro Pezzini
- Department of Clinical and
Experimental Sciences, Neurology Clinic, University of Brescia, Italy
| | - Janika Kõrv
- Department of Neurology and
Neurosurgery, University of Tartu, Estonia
| | | | | | - Christian Enzinger
- Division of Neuroradiology, Vascular
and Interventional Radiology, Medical University of Graz, Austria
| | - Dalius Jatuzis
- Department of Neurology and
Neurosurgery, Center for Neurology, Vilnius University, Lithuania
| | - Bob Siegerink
- Centre for Stroke Research Berlin,
Charité Universitätsmedizin Berlin, Germany
| | - Patricia Martínez-Sánchez
- Department of Neurology and Stroke
Centre, IdiPAZ Health Research Institute, La Paz University Hospital, Autonoma of
Madrid University, Spain
| | - Armin J Grau
- Department of Neurology, Klinikum
Ludwigshafen, Germany
| | | | - Per-Henrik Groop
- Folkhälsan Institute of Genetics,
Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki,
Finland
| | - Sylvain Lanthier
- Division of Neurology and Research
Centre, Centre Hospitalier de l'Université de Montréal (CHUM), Canada
| | - Hugo Ten Cate
- Department of Internal Medicine,
Cardiovascular Research Institute Maastricht, The Netherlands
| | - Pirkko Pussinen
- Oral and Maxillofacial Diseases,
University of Helsinki and Helsinki University Hospital, Finland
| | - Susanna Paju
- Oral and Maxillofacial Diseases,
University of Helsinki and Helsinki University Hospital, Finland
| | - Juha Sinisalo
- Department of Cardiology, Heart and
Lung Center, Helsinki University Hospital, Finland
| | - Mika Lehto
- Department of Cardiology, Heart and
Lung Center, Helsinki University Hospital, Finland
| | - Arne Lindgren
- Department of Clinical Sciences Lund,
Neurology, Lund University, Sweden
- Department of Neurology and
Rehabilitation Medicine, Skåne University Hospital, Lund, Sweden
| | - José Ferro
- Department of Neurosciences
(Neurology), Hospital de Santa Maria, University of Lisbon, Portugal
| | - Steven Kittner
- Department of Neurology, Baltimore
Veterans Administration Hospital, USA
- University of Maryland, USA
| | - Franz Fazekas
- Department of Neurology, Medical
University of Graz, Austria
| | - Eva Gerdts
- Department of Clinical Science,
University of Bergen, Norway
| | - Turgut Tatlisumak
- Department of Neurology, Helsinki
University Hospital, Finland
- Department of Clinical Neuroscience,
Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of
Gothenburg, Sweden
- Department of Neurology, Sahlgrenska
University Hospital, Sweden
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24
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Tse G, Chan YWF, Keung W, Yan BP. Electrophysiological mechanisms of long and short QT syndromes. IJC HEART & VASCULATURE 2017; 14:8-13. [PMID: 28382321 PMCID: PMC5368285 DOI: 10.1016/j.ijcha.2016.11.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 11/19/2016] [Indexed: 12/21/2022]
Abstract
The QT interval on the human electrocardiogram is normally in the order of 450 ms, and reflects the summated durations of action potential (AP) depolarization and repolarization of ventricular myocytes. Both prolongation and shortening in the QT interval have been associated with ventricular tachy-arrhythmias, which predispose affected individuals to sudden cardiac death. In this article, the molecular determinants of the AP duration and the causes of long and short QT syndromes (LQTS and SQTS) are explored. This is followed by a review of the recent advances on their arrhythmogenic mechanisms involving reentry and/or triggered activity based on experiments conducted in mouse models. Established and novel clinical risk markers based on the QT interval for the prediction of arrhythmic risk and cardiovascular mortality are presented here. It is concluded by a discussion on strategies for the future rational design of anti-arrhythmic agents.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, PR China
| | - Yin Wah Fiona Chan
- Department of Psychology, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Wendy Keung
- Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, SAR, PR China
| | - Bryan P Yan
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, PR China
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia
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25
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Shin ES, Lam YY, Her AY, Brachmann J, Jung F, Park JW. Incremental diagnostic value of combined quantitative and qualitative parameters of magnetocardiography to detect coronary artery disease. Int J Cardiol 2017; 228:948-952. [PMID: 27912204 DOI: 10.1016/j.ijcard.2016.11.165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 11/06/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND/OBJECTIVES Magnetocardiography (MCG) has been proposed as a non-invasive and functional technique with high accuracy for diagnosis of myocardial ischemia. This study sought to investigate the incremental diagnostic value of combined quantitative and qualitative parameters of MCG to detect coronary artery disease (CAD). METHODS Ninety six patients with suspected CAD who underwent coronary angiography were enrolled in the analysis to test the diagnostic accuracy of 2 MCG parameters (a quantitative parameter of the percent change of ST-segment fluctuation score and a qualitative parameter of non-dipole phenomenon). RESULTS The best cut-off value for the percent change of ST-segment fluctuation score was -51.0%. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 78.1, 73.9, 82.0, 79.1, and 77.4, in the percent change of ST-segment fluctuation score and 86.5, 84.8, 88.0, 86.7, and 86.3 in non-dipole phenomenon. The area under the curve of receiver-operating characteristics was 0.79 for the percent change of ST-segment fluctuation score and 0.86 for non-dipole phenomenon (p<0.001). However, the incorporation of non-dipole phenomenon into a model with the percent change of ST-segment fluctuation score significantly improved C-statistics, indicating the enhancement of diagnostic performance in the detection of significant CAD (0.790 to 0.930; p<0.001). CONCLUSIONS Qualitative assessment of non-dipole phenomenon has a better diagnostic value than the quantitative parameter of percent change of ST-segment fluctuation score in the detection of significant CAD. Furthermore, this study found that the incorporation of non-dipole phenomenon into the percent change of ST-segment fluctuation score significantly improved the diagnostic performance of CAD detection.
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Affiliation(s)
- Eun-Seok Shin
- Department of Cardiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea
| | - Yat-Yin Lam
- Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong
| | - Ae-Young Her
- Division of Cardiology, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, South Korea
| | | | - Friedrich Jung
- Institute of Biomaterial Science and Berlin-Brandenburg, Center for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany
| | - Jai-Wun Park
- Coburg Hospital, 2nd Medical Department, Coburg, Germany.
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26
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Kawakami S, Takaki H, Hashimoto S, Kimura Y, Nakashima T, Aiba T, Kusano KF, Kamakura S, Yasuda S, Sugimachi M. Utility of High-Resolution Magnetocardiography to Predict Later Cardiac Events in Nonischemic Cardiomyopathy Patients With Normal QRS Duration. Circ J 2016; 81:44-51. [PMID: 27853097 DOI: 10.1253/circj.cj-16-0683] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Nonischemic dilated cardiomyopathy (NIDCM) patients, even those with a narrow QRS, are at increased risk for major adverse cardiac events (MACE). We hypothesized that 64-channel magnetocardiography (MCG) would be useful to detect prognostic left intraventricular disorganized conduction (LiDC) by overcoming the limitations of fragmented QRS (fQRS, qualitative definitions, low specificity) and late potential (abnormality undetectable in earlier QRS).Methods and Results:We evaluated LiDC on MCG, defined as significant deviation from a global clockwise left ventricular (LV) activation pattern, and conventional noninvasive predictors of MACE, including fQRS and late potential, in 51 NIDCM patients with narrow QRS (LV ejection fraction, 22±7%; QRS duration, 99±11 ms). MACE was defined as cardiac death, lethal ventricular arrhythmias, or LV assist device (LVAD) implantation. LiDC was present in 22 patients. Baseline characteristics were comparable between patients with and without LiDC, except for the ratio of positive late potential. During a mean follow-up of 2.9 years, MACE developed in 16 NIDCM patients (3 cardiac deaths, 9 lethal ventricular arrhythmias, and 4 LVAD). MACE was more incident in patients with LiDC (13/22) than in those without (3/29, P<0.001). Multivariate analysis revealed LiDC, but not fQRS or late potential, as the strongest independent predictor of MACE (hazard ratio 4.28, 95% confidence interval 1.30-19.39, P=0.015). CONCLUSIONS MCG accurately depicts LiDC, a promising noninvasive predictor of MACE in patients with NIDCM and normal QRS.
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Affiliation(s)
- Shoji Kawakami
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center
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Rat Magnetocardiography Using a Flux-Gate Sensor Based on Iron Garnet Films. BIOMEDICAL ENGINEERING-MEDITSINSKAYA TEKNIKA 2016. [DOI: 10.1007/s10527-016-9628-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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28
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Her AY, Park JW. Repolarization Heterogeneity of Magnetocardiography Predicts Long-Term Prognosis in Patients with Acute Myocardial Infarction. Yonsei Med J 2016; 57:1305-6. [PMID: 27593855 PMCID: PMC5011259 DOI: 10.3349/ymj.2016.57.6.1305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Indexed: 11/27/2022] Open
Affiliation(s)
- Ae Young Her
- Division of Cardiology, Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea
- Department of Cardiology, Angiology, and Pneumology, Coburg Hospital, Coburg, Germany
| | - Jai Wun Park
- Department of Cardiology, Angiology, and Pneumology, Coburg Hospital, Coburg, Germany
- Department of Cardiology, Charite University Hospital, Berlin, Germany.
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29
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Bang WD, Kim K, Lee YH, Kwon H, Park Y, Pak HN, Ko YG, Lee M, Joung B. Repolarization Heterogeneity of Magnetocardiography Predicts Long-Term Prognosis in Patients with Acute Myocardial Infarction. Yonsei Med J 2016; 57:1339-46. [PMID: 27593860 PMCID: PMC5011264 DOI: 10.3349/ymj.2016.57.6.1339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/25/2016] [Accepted: 04/25/2016] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Magnetocardiography (MCG) has been proposed as a noninvasive, diagnostic tool for risk-stratifying patients with acute myocardial infarction (AMI). This study evaluated whether MCG predicts long-term prognosis in AMI. MATERIALS AND METHODS In 124 AMI patients (95 males, mean age 60±11 years), including 39 with ST-elevation myocardial infarction, a 64-channel MCG was performed within 2 days after AMI. During a mean follow-up period of 6.1 years, major adverse cardiac events (MACE) were evaluated. RESULTS MACE occurred in 31 (25%) patients, including 20 revascularizations, 8 deaths, and 3 re-infarctions. Non-dipole patterns were observed at the end of the T wave in every patients. However, they were observed at T-peak in 77% (24/31) and 54% (50/93) of patients with and without MACE, respectively (p=0.03). Maximum current, field map angles, and distance dynamics were not different between groups. In the multivariate analysis, patients with non-dipole patterns at T-peak had increased age- and gender-adjusted hazard ratios for MACE (hazard ratio 2.89, 95% confidence interval 1.20-6.97, p=0.02) and lower cumulative MACE-free survival than those with dipole patterns (p=0.02). CONCLUSION Non-dipole patterns at T-peak were more frequently observed in patients with MACE and were related to poor long-term prognosis. Thus, repolarization heterogeneity measured by MCG may be a useful predictor for AMI prognosis.
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Affiliation(s)
- Woo Dae Bang
- Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Department of Cardiology, University of Ulsan College of Medicine, Gangneung Asan Hospital, Gangneung, Korea
| | - Kiwoong Kim
- Bio-Signal Research Center, Korea Research Institute of Standards and Science, Daejeon, Korea
| | - Yong Ho Lee
- Bio-Signal Research Center, Korea Research Institute of Standards and Science, Daejeon, Korea
| | - Hyukchan Kwon
- Bio-Signal Research Center, Korea Research Institute of Standards and Science, Daejeon, Korea
| | - Yongki Park
- Bio-Signal Research Center, Korea Research Institute of Standards and Science, Daejeon, Korea
| | - Hui Nam Pak
- Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Young Guk Ko
- Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Moonhyoung Lee
- Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Boyoung Joung
- Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
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30
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Alday EAP, Ni H, Zhang C, Colman MA, Gan Z, Zhang H. Comparison of Electric- and Magnetic-Cardiograms Produced by Myocardial Ischemia in Models of the Human Ventricle and Torso. PLoS One 2016; 11:e0160999. [PMID: 27556808 PMCID: PMC4996509 DOI: 10.1371/journal.pone.0160999] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022] Open
Abstract
Myocardial ventricular ischemia arises from a lack of blood supply to the heart, which may cause abnormal repolarization and excitation wave conduction patterns in the tissue, leading to cardiac arrhythmias and even sudden death. Current diagnosis of cardiac ischemia by the 12-lead electrocardiogram (ECG) has limitations as they are insensitive in many cases and may show unnoticeable differences to normal patterns. As the magnetic field provides extra information on cardiac excitation and is more sensitive to tangential currents to the surface of the chest, whereas the electric field is more sensitive to flux currents, it has been hypothesized that the magnetocardiogram (MCG) may provide a complementary method to the ECG in ischemic diagnosis. However, it is unclear yet about the differences in sensitivity regions of body surface ECG and MCG signals to ischemic conditions. The aim of this study was to investigate such differences by using 12-, 36- ECG and 36-MCG computed from multi-scale biophysically detailed computational models of the human ventricles and torso in both control and ischemic conditions. It was shown that ischemia produced changes in the ECG and MCG signals in the QRS complex, T-wave and ST-segment, with greater relative differences seen in the 36-lead ECG and MCG as compared to the 12-leads ECG (34% and 37% vs 26%, respectively). The 36-lead ECG showed more averaged sensitivity than the MCG in the change of T-wave due to ischemia (37% vs 32%, respectively), whereas the MCG showed greater sensitivity than the ECG in the change of the ST-segment (50% vs 40%, respectively). In addition, both MCG and ECG showed regional-dependent changes to ischemia, but with MCG showing a stronger correlation between ischemic region in the heart. In conclusion, MCG shows more sensitivity than ECG in response to ischemia, which may provide an alternative method for the diagnosis of ischemia.
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Affiliation(s)
- Erick A. Perez Alday
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Haibo Ni
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Chen Zhang
- Applied superconductivity Research Center, School of Physics, Peking University, Beijing, China
| | - Michael A. Colman
- Theoretical Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Zizhao Gan
- Applied superconductivity Research Center, School of Physics, Peking University, Beijing, China
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
- * E-mail:
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31
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Tse G, Yan BP, Chan YWF, Tian XY, Huang Y. Reactive Oxygen Species, Endoplasmic Reticulum Stress and Mitochondrial Dysfunction: The Link with Cardiac Arrhythmogenesis. Front Physiol 2016; 7:313. [PMID: 27536244 PMCID: PMC4971160 DOI: 10.3389/fphys.2016.00313] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/11/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cardiac arrhythmias represent a significant problem globally, leading to cerebrovascular accidents, myocardial infarction, and sudden cardiac death. There is increasing evidence to suggest that increased oxidative stress from reactive oxygen species (ROS), which is elevated in conditions such as diabetes and hypertension, can lead to arrhythmogenesis. METHOD A literature review was undertaken to screen for articles that investigated the effects of ROS on cardiac ion channel function, remodeling and arrhythmogenesis. RESULTS Prolonged endoplasmic reticulum stress is observed in heart failure, leading to increased production of ROS. Mitochondrial ROS, which is elevated in diabetes and hypertension, can stimulate its own production in a positive feedback loop, termed ROS-induced ROS release. Together with activation of mitochondrial inner membrane anion channels, it leads to mitochondrial depolarization. Abnormal function of these organelles can then activate downstream signaling pathways, ultimately culminating in altered function or expression of cardiac ion channels responsible for generating the cardiac action potential (AP). Vascular and cardiac endothelial cells become dysfunctional, leading to altered paracrine signaling to influence the electrophysiology of adjacent cardiomyocytes. All of these changes can in turn produce abnormalities in AP repolarization or conduction, thereby increasing likelihood of triggered activity and reentry. CONCLUSION ROS plays a significant role in producing arrhythmic substrate. Therapeutic strategies targeting upstream events include production of a strong reducing environment or the use of pharmacological agents that target organelle-specific proteins and ion channels. These may relieve oxidative stress and in turn prevent arrhythmic complications in patients with diabetes, hypertension, and heart failure.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
| | - Yin W. F. Chan
- Department of Psychology, School of Biological Sciences, University of CambridgeCambridge, UK
| | - Xiao Yu Tian
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
| | - Yu Huang
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
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32
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Tse G, Sun B, Wong ST, Tse V, Yeo JM. Anti-arrhythmic effects of hypercalcemia in hyperkalemic, Langendorff-perfused mouse hearts. Biomed Rep 2016; 5:301-310. [PMID: 27588173 PMCID: PMC4998139 DOI: 10.3892/br.2016.735] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/31/2016] [Indexed: 12/25/2022] Open
Abstract
The present study examined the ventricular arrhythmic and electrophysiological properties during hyperkalemia (6.3 mM [K+] vs. 4 mM in normokalemia) and anti-arrhythmic effects of hypercalcemia (2.2 mM [Ca2+]) in Langendorff-perfused mouse hearts. Monophasic action potential recordings were obtained from the left ventricle during right ventricular pacing. Hyperkalemia increased the proportion of hearts showing provoked ventricular tachycardia (VT) from 0 to 6 of 7 hearts during programmed electrical stimulation (Fisher's exact test, P<0.05). It shortened the epicardial action potential durations (APDx) at 90, 70, 50 and 30% repolarization and ventricular effective refractory periods (VERPs) (analysis of variance, P<0.05) without altering activation latencies. Endocardial APDx and VERPs were unaltered. Consequently, ∆APDx (endocardial APDx-epicardial APDx) was increased, VERP/latency ratio was decreased and critical intervals for reexcitation (APD90-VERP) were unchanged. Hypercalcemia treatment exerted anti-arrhythmic effects during hyperkalemia, reducing the proportion of hearts showing VT to 1 of 7 hearts. It increased epicardial VERPs without further altering the remaining parameters, returning VERP/latency ratio to normokalemic values and also decreased the critical intervals. In conclusion, hyperkalemia exerted pro-arrhythmic effects by shortening APDs and VERPs. Hypercalcemia exerted anti-arrhythmic effects by reversing VERP changes, which scaled the VERP/latency ratio and critical intervals.
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Affiliation(s)
- Gary Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, SAR, P.R. China
| | - Bing Sun
- Department of Cardiology, Tongji University Affiliated Tongji Hospital, Shanghai 200065, P.R. China
| | | | - Vivian Tse
- Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Jie Ming Yeo
- School of Medicine, Imperial College London, London SW7 2AZ, UK
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Tse G, Lai ETH, Yeo JM, Tse V, Wong SH. Mechanisms of Electrical Activation and Conduction in the Gastrointestinal System: Lessons from Cardiac Electrophysiology. Front Physiol 2016; 7:182. [PMID: 27303305 PMCID: PMC4885840 DOI: 10.3389/fphys.2016.00182] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/06/2016] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal (GI) tract is an electrically excitable organ system containing multiple cell types, which coordinate electrical activity propagating through this tract. Disruption in its normal electrophysiology is observed in a number of GI motility disorders. However, this is not well characterized and the field of GI electrophysiology is much less developed compared to the cardiac field. The aim of this article is to use the established knowledge of cardiac electrophysiology to shed light on the mechanisms of electrical activation and propagation along the GI tract, and how abnormalities in these processes lead to motility disorders and suggest better treatment options based on this improved understanding. In the first part of the article, the ionic contributions to the generation of GI slow wave and the cardiac action potential (AP) are reviewed. Propagation of these electrical signals can be described by the core conductor theory in both systems. However, specifically for the GI tract, the following unique properties are observed: changes in slow wave frequency along its length, periods of quiescence, synchronization in short distances and desynchronization over long distances. These are best described by a coupled oscillator theory. Other differences include the diminished role of gap junctions in mediating this conduction in the GI tract compared to the heart. The electrophysiology of conditions such as gastroesophageal reflux disease and gastroparesis, and functional problems such as irritable bowel syndrome are discussed in detail, with reference to ion channel abnormalities and potential therapeutic targets. A deeper understanding of the molecular basis and physiological mechanisms underlying GI motility disorders will enable the development of better diagnostic and therapeutic tools and the advancement of this field.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Eric Tsz Him Lai
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Jie Ming Yeo
- School of Medicine, Imperial College LondonLondon, UK
| | - Vivian Tse
- Department of Physiology, McGill UniversityMontreal, QC, Canada
| | - Sunny Hei Wong
- Department of Medicine and Therapeutics, Institute of Digestive Disease, LKS Institute of Health Sciences, Chinese University of Hong KongHong Kong, China
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Tse G, Lai ETH, Yeo JM, Yan BP. Electrophysiological Mechanisms of Bayés Syndrome: Insights from Clinical and Mouse Studies. Front Physiol 2016; 7:188. [PMID: 27303306 PMCID: PMC4886053 DOI: 10.3389/fphys.2016.00188] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/10/2016] [Indexed: 12/11/2022] Open
Abstract
Bayés syndrome is an under-recognized clinical condition characterized by inter-atrial block (IAB). This is defined electrocardiographically as P-wave duration > 120 ms and can be categorized into first, second and third degree IAB. It can be caused by inflammatory conditions such as systemic sclerosis and rheumatoid arthritis, abnormal protein deposition in cardiac amyloidosis, or neoplastic processes invading the inter-atrial conduction system, such as primary cardiac lymphoma. It may arise transiently during volume overload, autonomic dysfunction or electrolyte disturbances from vomiting. In other patients without an obvious cause, the predisposing factors are diabetes mellitus, hypertensive heart disease, and hypercholesterolemia. IAB has a strong association with atrial arrhythmogenesis, left atrial enlargement (LAE), and electro-mechanical discordance, increasing the risk of cerebrovascular accidents as well as myocardial and mesenteric ischemia. The aim of this review article is to synthesize experimental evidence on the pathogenesis of IAB and its underlying molecular mechanisms. Current medical therapies include anti-fibrotic, anti-arrhythmic and anti-coagulation agents, whereas interventional options include atrial resynchronization therapy by single or multisite pacing. Future studies will be needed to elucidate the significance of the link between IAB and atrial tachyarrhythmias in patients with different underlying etiologies and optimize the management options in these populations.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Eric Tsz Him Lai
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Jie Ming Yeo
- School of Medicine, Imperial College LondonLondon, UK
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, The Chinese University of Hong KongHong Kong, China
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
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Chang YC, Wu CC, Lin CH, Wu YW, Yang YC, Chang TJ, Jiang YD, Chuang LM. Early Myocardial Repolarization Heterogeneity Is Detected by Magnetocardiography in Diabetic Patients with Cardiovascular Risk Factors. PLoS One 2015; 10:e0133192. [PMID: 26185995 PMCID: PMC4505945 DOI: 10.1371/journal.pone.0133192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 06/23/2015] [Indexed: 11/18/2022] Open
Abstract
Multi-channel magnetocardiography (MCG) is a sensitive technique to map spatial ventricular repolarization with high resolution and reproducibility. Spatial ventricular repolarization heterogeneity measured by MCG has been shown to accurately detect and localize myocardial ischemia. Here, we explored whether these measurements correlated with cardiovascular risk factors in patients with type 2 diabetes. Two hundreds and seventy-seven type 2 diabetic patients without known coronary artery disease (CAD) and arrhythmia were recruited consecutively from the outpatient clinic of National Taiwan University Hospital. The spatially distributed QTc contour maps were constructed with 64-channel MCG using the superconducting quantum interference device (SQUID) system. Indices of myocardial repolarization heterogeneity including the smoothness index of QTc (SI-QTc) and QTc dispersion were derived and analyzed for association with conventional cardiovascular risk factors. SI-QTc correlated strongly with the QTc dispersion (r = 0.70, p <0.0001). SI-QTc was significantly higher in patients with presence of metabolic syndrome in comparison to those without metabolic syndrome (8.56 vs. 7.96 ms, p = 0.02). In univariate correlation analyses, QTc dispersion was associated with smoking status (average 79.90, 83.83, 86.51, and 86.00 ms for never smokers, ex-smokers, current smokers reporting less than 10 cigarettes daily, and current smoker reporting more than 10 cigarettes daily, respectively, p = 0.03), body weight (r = 0.15, p = 0.01), and hemoglobin A1c (r = 0.12, p = 0.04). In stepwise multivariate regression analyses, QTc dispersion was associated with smoking (p = 0.02), body weight (p = 0.04), total cholesterol levels (p = 0.05), and possibly estimated glomerular filtration rate (p = 0.07). In summary, spatial heterogeneity of myocardial repolarization measured by MCG is positively associated cardiovascular risk factors including adiposity, smoking, and total cholesterol levels.
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Affiliation(s)
- Yi-Cheng Chang
- Graduate Institute of Medical Genomics and Proteomics, National Taiwan University, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, HsinChu branch, HsinChu, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medicine, College of Medicine, National Taiwan University, Taipei; Taiwan
| | - Chau-Chung Wu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Primary Care Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Hung Lin
- Department of Internal Medicine, Taipei Medical University Hospital, Taipei Taiwan
| | - Yen-Wen Wu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Nuclear Medicine and Cardiology Division of Cardiovascular Medical Center, Far Eastern Memorial Hospital, New Taipei City, Taiwan
- Departments of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
- National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Ying-Chieh Yang
- Department of Internal Medicine, National Taiwan University Hospital, HsinChu branch, HsinChu, Taiwan
| | - Tien-Jyun Chang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medicine, College of Medicine, National Taiwan University, Taipei; Taiwan
| | - Yi-Der Jiang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medicine, College of Medicine, National Taiwan University, Taipei; Taiwan
| | - Lee-Ming Chuang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medicine, College of Medicine, National Taiwan University, Taipei; Taiwan
- Institute of Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- * E-mail:
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Mäntynen V, Konttila T, Stenroos M. Investigations of sensitivity and resolution of ECG and MCG in a realistically shaped thorax model. Phys Med Biol 2014; 59:7141-58. [PMID: 25365547 DOI: 10.1088/0031-9155/59/23/7141] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Solving the inverse problem of electrocardiography (ECG) and magnetocardiography (MCG) is often referred to as cardiac source imaging. Spatial properties of ECG and MCG as imaging systems are, however, not well known. In this modelling study, we investigate the sensitivity and point-spread function (PSF) of ECG, MCG, and combined ECG+MCG as a function of source position and orientation, globally around the ventricles: signal topographies are modelled using a realistically-shaped volume conductor model, and the inverse problem is solved using a distributed source model and linear source estimation with minimal use of prior information. The results show that the sensitivity depends not only on the modality but also on the location and orientation of the source and that the sensitivity distribution is clearly reflected in the PSF. MCG can better characterize tangential anterior sources (with respect to the heart surface), while ECG excels with normally-oriented and posterior sources. Compared to either modality used alone, the sensitivity of combined ECG+MCG is less dependent on source orientation per source location, leading to better source estimates. Thus, for maximal sensitivity and optimal source estimation, the electric and magnetic measurements should be combined.
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Affiliation(s)
- Ville Mäntynen
- Department of Biomedical Engineering and Computational Science, Aalto University, Espoo, PO Box 12200, FI-00076, AALTO, Finland. BioMag Laboratory, HUS Medical Imaging Center, Helsinki, PO Box 340, FI-00029, HUS, Finland
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Ha T, Kim K, Lim S, Yu KK, Kwon H. Three-dimensional reconstruction of a cardiac outline by magnetocardiography. IEEE Trans Biomed Eng 2014; 62:60-9. [PMID: 25020011 DOI: 10.1109/tbme.2014.2336671] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A 3-D cardiac visualization is significantly helpful toward clinical applications of magnetocardiography (MCG), but the cardiac reconstruction requires a segmentation process using additional image modalities. This paper proposes a 3-D cardiac outline reconstruction method using only MCG measurement data without further imaging techniques. The cardiac outline was reconstructed by a combination of both spatial filtering and coherence mapping method. The strength of cardiac activities was first estimated by the array-gain constraint minimum-norm spatial filter with recursively updated gram matrix (AGMN-RUG). Then, waveforms were reconstructed at whole source grids, and the maximum source points of an atrium and ventricle were selected as a reference, respectively. Next, the coherence between each maximum source point and whole source points was compared by the coherence mapping method. A reconstructed cardiac outline was validated by comparing with an overlapped volume ratio when the reconstructed volume was identically matched with the original volume. The results obtained by the AGMN-RUG were compared to the results by other spatial filters. The accuracy of numerical simulation and phantom experiment by the AGMN-RUG was superior 10% and 8%, respectively, than the accuracy by the standardized low-resolution electromagnetic tomography. This accuracy demonstrated the efficacy of the proposed 3-D cardiac reconstruction method.
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Zhang X, Cheng X, Liu H, Zheng C, Rao K, Fang Y, Zhou H, Xiong S. Identification of key genes and crucial modules associated with coronary artery disease by bioinformatics analysis. Int J Mol Med 2014; 34:863-9. [PMID: 24969630 DOI: 10.3892/ijmm.2014.1817] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 05/28/2014] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to identify key genes associated with coronary artery disease (CAD) and to explore the related signaling pathways. Gene expression profiles of 110 CAD and 112 non-CAD, healthy patients [CAD index (CADi) >23 and =0, respectively] were downloaded from the Gene Expression Omnibus (GEO) database (accession: GSE12288). The differentially expressed genes (DEGs) in CAD were identified using t-tests, and protein-protein interaction (PPI) networks for these DEGs were constructed using the Search Tool for the Retrieval of InteractiNg Genes (STRING) database. The Database for Annotation, Visualization and Integrated Discovery (DAVID) tool was used to identify potentially enriched biological processes (BP) among the DEGs using Gene Ontology (GO) terms, and to identify the related pathways using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. In addition, expression-activated subnetworks (crucial modules) of the constructed PPI networks were identified using the jActiveModule plug-in, and their topological properties were analyzed using NetworkAnalyzer, both available from Cytoscape. The patient specimens were classified as grade I, II and III based on CADi values. There were 151 DEGs in grade I, 362 in grade II and 425 in grade III. In the PPI network, the gene GRB2, encoding the growth factor receptor-bound protein 2, was the only common DEG among the three grades. In addition, 10 crucial modules were identified in the PPIs, 4 of which showed significant enrichment for GO BP terms. In the 12 nodes with the highest betweenness centrality, we found two genes, encoding GRB2 and the heat shock 70 kDa protein 8 (HSPA8). Moreover, the chemokine and focal adhesion signaling pathways were selected based on their relative abundance in CAD. The GRB2 and HSPA8 proteins, as well as the chemokine and focal adhension signaling pathways, might therefore be critical for the development of CAD.
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Affiliation(s)
- Xuemei Zhang
- Department of Cardiology, Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
| | - Xiaoshu Cheng
- Department of Cardiology, Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
| | - Huifeng Liu
- Department of Cardiology, Xiaolan People's Hospital, Zhongshan, Guangdong 528415, P.R. China
| | - Chunhua Zheng
- Department of Cardiology, Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
| | - Kunrui Rao
- Department of Cardiology, Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
| | - Yi Fang
- Department of Cardiology, Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
| | - Hairong Zhou
- Department of Cardiology, Second People's Hospital, Mudanjiang, Heilongjiang 157000, P.R. China
| | - Shenghe Xiong
- Department of Cardiology, Third Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330008, P.R. China
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Kucuk U, Olgun Kucuk H, Balta S, Arslan Z. Tiny magnetomers and future of magnetocardiography. Int J Cardiol 2014; 172:e268. [PMID: 24508109 DOI: 10.1016/j.ijcard.2013.12.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/27/2013] [Indexed: 11/19/2022]
Affiliation(s)
- Ugur Kucuk
- Van Army District Hospital, Department of Cardiology, Van, Turkey
| | - Hilal Olgun Kucuk
- Education and Research Hospital, Department of Cardiology, Van, Turkey
| | - Sevket Balta
- Gulhane Military Medical Academy, Department of Cardiology, Ankara, Turkey
| | - Zekeriya Arslan
- Gulhane Military Medical Academy, Department of Cardiology, Ankara, Turkey
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Spatial repolarization heterogeneity detected by magnetocardiography correlates with cardiac iron overload and adverse cardiac events in beta-thalassemia major. PLoS One 2014; 9:e86524. [PMID: 24475137 PMCID: PMC3903540 DOI: 10.1371/journal.pone.0086524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 12/10/2013] [Indexed: 11/19/2022] Open
Abstract
Background Patients with transfusion-dependent beta-thalassemia major (TM) are at risk for myocardial iron overload and cardiac complications. Spatial repolarization heterogeneity is known to be elevated in patients with certain cardiac diseases, but little is known in TM patients. The purpose of this study was to evaluate spatial repolarization heterogeneity in patients with TM, and to investigate the relationships between spatial repolarization heterogeneity, cardiac iron load, and adverse cardiac events. Methods and Results Fifty patients with TM and 55 control subjects received 64-channel magnetocardiography (MCG) to determine spatial repolarization heterogeneity, which was evaluated by a smoothness index of QTc (SI-QTc), a standard deviation of QTc (SD-QTc), and a QTc dispersion. Left ventricular function and myocardial T2* values were assessed by cardiac magnetic resonance. Patients with TM had significantly greater SI-QTc, SD-QTc, and QTc dispersion compared to the control subjects (all p values<0.001). Spatial repolarization heterogeneity was even more pronounced in patients with significant iron overload (T2*<20 ms, n = 20) compared to those with normal T2* (all p values<0.001). Loge cardiac T2* correlated with SI-QTc (r = −0.609, p<0.001), SD-QTc (r = −0.572, p<0.001), and QTc dispersion (r = −0.622, p<0.001), while all these indices had no relationship with measurements of the left ventricular geometry or function. At the time of study, 10 patients had either heart failure or arrhythmia. All 3 indices of repolarization heterogeneity were related to the presence of adverse cardiac events, with areas under the receiver operating characteristic curves (ranged between 0.79 and 0.86), similar to that of cardiac T2*. Conclusions Multichannel MCG demonstrated that patients with TM had increased spatial repolarization heterogeneity, which is related to myocardial iron load and adverse cardiac events.
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Juárez-Aguirre R, Domínguez-Nicolás SM, Manjarrez E, Tapia JA, Figueras E, Vázquez-Leal H, Aguilera-Cortés LA, Herrera-May AL. Digital signal processing by virtual instrumentation of a MEMS magnetic field sensor for biomedical applications. SENSORS 2013; 13:15068-84. [PMID: 24196434 PMCID: PMC3871138 DOI: 10.3390/s131115068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/24/2013] [Accepted: 10/28/2013] [Indexed: 11/16/2022]
Abstract
We present a signal processing system with virtual instrumentation of a MEMS sensor to detect magnetic flux density for biomedical applications. This system consists of a magnetic field sensor, electronic components implemented on a printed circuit board (PCB), a data acquisition (DAQ) card, and a virtual instrument. It allows the development of a semi-portable prototype with the capacity to filter small electromagnetic interference signals through digital signal processing. The virtual instrument includes an algorithm to implement different configurations of infinite impulse response (IIR) filters. The PCB contains a precision instrumentation amplifier, a demodulator, a low-pass filter (LPF) and a buffer with operational amplifier. The proposed prototype is used for real-time non-invasive monitoring of magnetic flux density in the thoracic cage of rats. The response of the rat respiratory magnetogram displays a similar behavior as the rat electromyogram (EMG).
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Affiliation(s)
- Raúl Juárez-Aguirre
- Micro and Nanotechnology Research Center, Universidad Veracruzana, Calzada Ruiz Cortines 455, Boca del Río 94294, Veracruz, Mexico; E-Mails: (R.J.-A.); (S.M.D.-N.)
| | - Saúl M. Domínguez-Nicolás
- Micro and Nanotechnology Research Center, Universidad Veracruzana, Calzada Ruiz Cortines 455, Boca del Río 94294, Veracruz, Mexico; E-Mails: (R.J.-A.); (S.M.D.-N.)
- Depto. Control Automático, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Av. IPN 2508, Col. Zacatenco 07360, D.F., Mexico
| | - Elías Manjarrez
- Institute of Physiology, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Colonia San Manuel, Puebla 72570, Puebla, Mexico; E-Mails: (E.M.); (J.A.T.)
| | - Jesús A. Tapia
- Institute of Physiology, Benemérita Universidad Autónoma de Puebla, 14 Sur 6301, Colonia San Manuel, Puebla 72570, Puebla, Mexico; E-Mails: (E.M.); (J.A.T.)
| | - Eduard Figueras
- Microelectronic Institute of Barcelona IMB-CNM, CSIC, Bellaterra 08193, Spain; E-Mail:
| | - Héctor Vázquez-Leal
- Electronic Instrumentation and Atmospheric Sciences School, Universidad Veracruzana, Gonzalo Aguirre Beltran S/N, Xalapa 91000, Veracruz, Mexico; E-Mail:
| | - Luz A. Aguilera-Cortés
- Depto. Ingeniería Mecánica, DICIS, Universidad de Guanajuato/Carretera Salamanca-Valle de Santiago km 3.5+1.8 km, Salamanca 36885, Guanajuato, Mexico; E-Mail:
| | - Agustín L. Herrera-May
- Micro and Nanotechnology Research Center, Universidad Veracruzana, Calzada Ruiz Cortines 455, Boca del Río 94294, Veracruz, Mexico; E-Mails: (R.J.-A.); (S.M.D.-N.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +52-229-775-2000 (ext. 11956); Fax: +52-229-921-6532
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Brisinda D, Venuti A, Sorbo AR, Fenici R. Magnetocardiographic demonstration of complex ventricular preexcitation resulting in ablation failure. Int J Cardiol 2013; 168:5046-8. [PMID: 23932861 DOI: 10.1016/j.ijcard.2013.07.215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 07/20/2013] [Indexed: 10/26/2022]
Affiliation(s)
- D Brisinda
- Clinical Physiology - Biomagnetism Center, Catholic University of Sacred Heart, Rome, Italy
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Fenici R, Brisinda D, Venuti A, Sorbo A. Thirty years of clinical magnetocardiography at the Catholic University of Rome: Diagnostic value and new perspectives for the treatment of cardiac arrhythmias. Int J Cardiol 2013; 168:5113-5. [PMID: 23958422 DOI: 10.1016/j.ijcard.2013.07.238] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 07/20/2013] [Accepted: 07/25/2013] [Indexed: 10/26/2022]
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