Detection of spatial repolarization abnormalities in patients with LQT1 and LQT2 forms of congenital long-QT syndrome

Kandori, Akihiko; Shimizu, Wataru; Yokokawa, Miki; Maruo, Takeshi; Kanzaki, Hideaki; Nakatani, Satoshi; Kamakura, Shiro; Miyatake, Kunio; Murakami, Masahiro; Miyashita, Tsuyoshi; Ogata, Kiyoshi; Tsukada, Keiji

doi:10.1088/0967-3334/23/4/301

Cited by 17 publications

(25 citation statements)

References 37 publications

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“…From MCG signals, a great deal of useful information concerning cardiac disease can be obtained: QT and QRS prolongation caused by myocardial abnormalities were studied using the late fields of MCG signals; [1][2][3]25 T wave deviation of MCG signal is used to detecting IHD. [1][2][3]26 These characteristics indicated MCG recording can provide value information for clinicians.…”

Section: Resultsmentioning

confidence: 99%

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A simplified HTc rf SQUID to analyze the human cardiac magnetic field

Zhang

Tang

et al. 2014

AIP Advances

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We have developed a four-channel high temperature radio-frequency superconducting quantum interference device (HTc rf SQUID) in a simple magnetically shielded room (MSR) that can be used to analyze the cardiac magnetic field. It is more robust and compact than existing systems. To achieve the high-quality magnetocardiographic signal, we explored new adaptive software gradiometry technology constructed by the first-order axial gradiometer with a baseline of 80mm, which can adjust its performance timely with the surrounding conditions. The magnetic field sensitivity of each channel was less than 100fT/√Hz in the white noise region. Especially, in the analysis of MCG signal data, we proposed the total transient mapping (TTM) technique to visualize current density map (CDM), then we focused to observe the time-varying behavior of excitation propagation and estimated the underlying currents at T wave. According to the clear 3D imaging, isomagnetic field and CDM, the position and distribution of a current source in the heart can be visualized. It is believed that our four-channel HTc rf SQUID magnetometer based on biomagnetic system is available to detect MCG signals with sufficient signal-to-noise (SNR) ratio. In addition, the CDM showed the macroscopic current activation pattern, in a way, it has established strong underpinnings for researching the cardiac microscopic movement mechanism and opening the way for its use in clinical diagnosis.

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Section: Resultsmentioning

confidence: 99%

“…Successful results have been reported in clinically relevant applications. [1][2][3][25][26][27][28] Our practical studies can provide 3D imaging, isomagnetic field maps and CMDs at T wave with sufficient spatial resolution. These results are considered as a major argument for IHD.…”

Section: Resultsmentioning

confidence: 99%

A simplified HTc rf SQUID to analyze the human cardiac magnetic field

Zhang

Tang

et al. 2014

AIP Advances

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“…Kandori et al calculated current arrow maps from MCG signals of fetuses and adults and identified spatial current dispersions in both the QRS complex and T-wave, which could be used to make a prenatal diagnosis and to distinguish between different LQTS forms in adults [47][48][49]. It was also the group around Kandori who used a whole-heart electrical-activation diagram (W-HEAD) model for visualization of the spatial time-variant activation of the whole heart.…”

Section: Rozkład Prądów Nasierdziowych U Pacjenta Z Ciasnym Zwężenimentioning

confidence: 99%

Special article Magnetocardiography in clinical cardiology. Status quo and future applications

Leithäuser¹,

Jung²,

Park³

2011

pwki

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215Magnetocardiography in clinical cardiology. Status quo and future applications Magnetokardiografia w kardiologii klinicznej. Stan obecny i przyszłe zastosowania B Bo or ri is s L Le ei it th hä äu us se er r 1 1 , , F Fr ri ie ed dr ri ic ch h J Ju un ng g 2 2 , , J Ja ai i--W Wu un n P Pa ar rk k Special article/Artykuł specjalny A b s t r a c tMagnetocardiography (MCG) is a non-contact, non-invasive technique for the assessment of electromagnetic activity of the human heart. Theoretical considerations and comparative studies indicate different information content between MCG and electrocardiography (ECG). Although many questions about cardiac pathophysiology and electrophysiology can be answered by MCG studies, measurement of biomagnetism is still only marginally recognized as a valuable tool. Although MCG instrumentation (SQUIDs, MSR) and operation (liquid helium) are expensive and not available at the bedside, the gain of information drawn from the cardiac magnetic field is worth the effort. The MCG has superior sensitivity for ischaemic myocardium both at rest and under stress. Therefore, it may change one's ideas of decision making about invasive procedures. Compared to scintigraphy, which is a cumbersome method with the need of radioactivity exposure to the patient, MCG is as easy as bicycle ergometry but with higher sensitivity. In terms of risk stratification for sudden cardiac death, it seems to be possible that MCG in the future will provide additional information as to which patient will not benefit from prophylactic defibrillator implantation. However, appropriate clinical studies are lacking. Most interestingly, MCG appears to be practical and informative in the diagnosis of cardiac arrhythmias, and has sufficient spatial accuracy necessary for clinical purposes. It seems realistic that MCG-based localization of arrhythmogenic spots may guide the operator's ablation catheter, e.g. in patients with relapsing AF after a first successful ablation procedure. There is enough room for fantasy which question in clinical cardiology remains to be answered by MCG. K Ke ey y w wo or rd ds s: : magnetocardiography, coronary heart disease, ischaemia, risk stratification, arrhythmia, atrial fibrillation S t r e s z c z e n i e Magnetokardiografia (ang. magnetocardiography, MCG) jest bezkontaktową, nieinwazyjną metodą pomiaru pola magnetycznego ludzkiego serca. Założenia teoretyczne oraz badania porównawcze wskazują, że MCG i EKG dostarczają odmiennych informacji. Pomiar pola magnetycznego jest nadal w niewielkim stopniu uważany za wartościowe narzędzie, pomimo że badania MCG mogą udzielić odpowiedzi na wiele pytań dotyczących patofizjologii serca i elektrofizjologii. Chociaż oprzyrządowanie konieczne do MCG (SQUIDs, MSR) i jego obsłu-ga (ciekły hel) są drogie i nie są dostępne jako badania przyłóżkowe, to informacja uzyskiwana z badań pola magnetycznego serca jest warta tych wysiłków. Magnetokardiografia charakteryzuje się większą czułością w wykrywaniu niedokrwienia miokardium zarówno w warunkach spoczynkow...

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“…A two-dimensional (2-D) current-arrow map (CAM) [13] has been proposed as a method for calculating pseudo-cardiac electrical current from MCG signals. Maps of this type are providing the basis for a new method of analyzing atrial excitation of normal subject [14], arrhythmia [15,16] and ischemic heart disease [17]. Furthermore, multiple activated regions during the ventricular depolarization have been visualized by using the anterior and posterior CAMs [18].…”

Section: Introductionmentioning

confidence: 99%

Visualization of three-dimensional cardiac electrical excitation using standard heart model and anterior and posterior magnetocardiogram

Ogata

Kandori

Miyashita

et al. 2006

Int J Cardiovasc Imaging

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Our aim in this study is to obtain novel three-dimensional (3-D) images of cardiac electrical excitation that include morphological information on the whole heart. We obtain these 3-D images by projecting anterior and posterior two-dimensional (2-D) current-arrow maps (CAMs) onto a 3-D standard heart model. This standard heart model is adjusted to the individual subject's heart position by using the coordinates of the sinus node, which are obtained from magnetocardiogram (MCG) signals. The anterior and posterior CAMs are calculated by taking the orthogonal partial derivatives of the normal component of the anterior and posterior MCGs. After adjusting the base current values of the anterior and posterior CAMs, the adjusted CAMs are projected onto the standard heart model. We generated the projected CAMs (PCAMs) of the six phases (atrial, and ventricular, excitation) for seven healthy subjects. The validity of PCAM was evaluated by extracting the maximal current directions and positions from the PCAMs. The maximal current directions and positions during each excitation phase were almost in the same in the seven healthy subjects. Therefore, the PCAMs give us a clear view of the anterior and posterior myocardial excitation for the respective electrophysiological phases.

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Detection of spatial repolarization abnormalities in patients with LQT1 and LQT2 forms of congenital long-QT syndrome

Cited by 17 publications

References 37 publications

A simplified HTc rf SQUID to analyze the human cardiac magnetic field

A simplified HTc rf SQUID to analyze the human cardiac magnetic field

Special article Magnetocardiography in clinical cardiology. Status quo and future applications

Visualization of three-dimensional cardiac electrical excitation using standard heart model and anterior and posterior magnetocardiogram

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