Magnetocardiographic studies of ventricular repolarization in old inferior myocardial infarction

Nomura, Masahiro; Nakaya, Yutaka; Fujino, Kazuya; Ishihara, S; Katayama, Megumi; Takeuchi, Akemi; Watanabe, Kenya; Hiasa, Yoshikazu; Aihara, Tsukasa; Mori, Hiromu

doi:10.1093/oxfordjournals.eurheartj.a059385

Cited by 22 publications

(7 citation statements)

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“…Although MCGs have unique fundamental principles, can be quantified using absolute scales [4] , and are less affected by the body tissues compared with 12-lead electrocardiograms (ECGs) [5] , their clinical utility has not been established. Several reports have described MCGs studies of His potentials [6,7] , ventricular repolarization abnormalities during sinus rhythm [8][9][10] , and arrhythmic foci in patients with premature contractions or Wolff-Parkinson-White syndrome [11][12][13][14] . However, there are very few MCG studies of reentrant arrhythmias.…”

Section: Introductionmentioning

confidence: 99%

Noninvasive, direct visualization of macro-reentrant circuits by using magnetocardiograms: initiation and persistence of atrial flutter

et al. 2003

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Aims We analysed the cardiac magnetic fields on the body surface to visualize electrical currents noninvasively during reentrant arrhythmias.Methods and results Seven patients with counterclockwise atrial flutter (AFL) were studied during 17 episodes of AFL using 64-channel magnetocardiograms (MCGs) and electrophysiological study. Eight of the episodes were paroxysmal AFL, in which MCGs were recorded from the time of spontaneous onset to the time of termination. We constructed iso-magnetic field maps of the tangential components and produced MCG animations. With respect to AFL initiation, an atrial premature complex induced AFL. Prior to the initiation of AFL, atrial fibrillation (AF) transiently occurred. The cardiac magnetic fields revealed a single peak during sinus rhythm or with premature complexes but a disorganized pattern during AF. When AF transformed to AFL, the magnetic fields changed from a disorganized pattern to a single peak at first and then evolved to a circular pattern. During persistent AFL, the magnetic source moved in a counterclockwise circuit.Conclusion MCG animation can be used to visualize the sequence in which a premature complex transforms sinus rhythm to AFL via AF. Our findings indicate that MCGs can be used to identify noninvasively the mechanisms responsible for atrial tachyarrhythmias.

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Section: Introductionmentioning

confidence: 99%

Noninvasive, direct visualization of macro-reentrant circuits by using magnetocardiograms: initiation and persistence of atrial flutter

et al. 2003

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“…The authors completed the concept of risk prediction in patients with dilated cardiomyopathy, showing that the prolongation of the end part of the T wave was related to malignant ventricular arrhythmias [64]. In terms of ischaemic heart disease, the results were in line with smaller studies on MCG late potentials done by other groups [65][66][67]. However, the clinical value of late potential analysis is under discussion [68] and analysis with MCG appears not to be of significant advantage when compared to highresolution ECG recordings [69].…”

Section: Boris Leithäuser Et Al Magnetocardiography In Clinical Cardmentioning

confidence: 52%

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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“…The results degrade slightly when using stress data. In this case induced ischemia appears in the repolarization phase, the ST segment of the MCG signals 19) . This alteration of the normal excitation can be well described by a distributed current model 5) , and what is usually done is to identify the area of the myocardium corresponding to the site of the conduction disturbances.…”

Section: Discussionmentioning

confidence: 99%

Single and Distributed Dipole Models Analysis of Cardiac Source Activation using MCG Signals

2010

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In biomagnetic inverse problems different models of the source activation can be used depending on the physiology of the problem. In this study we compared different source models to perform current source reconstruction in MCG. We first considered a single dipole source model using a non linear minimization algorithm to localize the source of the heart activity in different segments of the MCG signals. We then repeated the same analyses using a distributed sources model and calculated an equivalent dipole located in the center of mass of all dipoles to compare it with the results of the single dipole model localization. The differences in the positions and orientations were evaluated under different conditions, for normal subjects at rest and after stress exercise test, using normal component and vector component data. Different configurations of the volume conductor model were used, to evaluate the influence of the geometry and of the conductivity inhomogeneities on the inverse solution. The results show that 3D data allow finding smaller differences between the single dipole and the equivalent dipole localized solutions.

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Magnetocardiographic studies of ventricular repolarization in old inferior myocardial infarction

Cited by 22 publications

References 0 publications

Noninvasive, direct visualization of macro-reentrant circuits by using magnetocardiograms: initiation and persistence of atrial flutter

Noninvasive, direct visualization of macro-reentrant circuits by using magnetocardiograms: initiation and persistence of atrial flutter

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

Single and Distributed Dipole Models Analysis of Cardiac Source Activation using MCG Signals

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