Multichannel biomagnetic system for study of electrical activity in the brain and heart.

Schneider, Sebastian; Hoenig, E; Reichenberger, Helmut; Abraham-Fuchs, K.; Moshage, Werner; Oppelt, A; Stefan, Hermann; Weikl, A; Wirth, Axel

doi:10.1148/radiology.176.3.2389043

Cited by 72 publications

(16 citation statements)

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“…The system is based on 37 first-order gradiometers arranged in a planar array with a diameter of 19 cm [11]. The measurements were conducted inside a magnetically shielded room.…”

Section: Instrumentationmentioning

confidence: 99%

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Clinical magnetocardiography: Experience with a biomagnetic multichannel system

et al. 1991

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The magnetic fields caused by the human heart's electrical activity were coherently recorded with a biomagnetic multichannel system (KRENIKON) during 1 to 10 minutes in 49 patients. 31 to 37 magnetic channels were recorded simultaneously with the ECG and respiration. Comparison of a magnetic index and the Sokolow-Lyon index to echocardiographic findings in the quantification of left ventricular hypertrophy demonstrated the superiority of the magnetocardiogram (MCG) as compared to the ECG. The magnetocardiographic investigation of patients with WPW-Syndrome, ventricular extrasystoles, ventricular tachycardia, and paced ventricular beats demonstrated that multichannel magnetocardiography permits the non-invasive three dimensional localization of arrhythmogenic tissue with high spatial accuracy.

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“…The system is based on 37 first-order gradiometers arranged in a planar array with a diameter of 19 cm [11]. The measurements were conducted inside a magnetically shielded room.…”

Section: Instrumentationmentioning

confidence: 99%

“…In 1988, a multichannel system KRENIKON ® was introduced. With up to 37 magnetic channels, it permits the coherent real-time registration of a sufficiently large field map for localization without repositioning of the sensors or the patient [11].…”

Section: Introductionmentioning

confidence: 99%

Clinical magnetocardiography: Experience with a biomagnetic multichannel system

et al. 1991

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“…However, it was not until the availability of multichannel SQUID systems installed in magnetically shielded rooms that the registration quality was sufficient for the development of clinical applications [7][8][9]. Making use of the available technology, we investigated the applicability and accuracy of multichannel magnetocardiographic recordings for non-invasive 3-dimensional localization in phantom and patient studies, by comparison to established reference methods, and, as a gold standard, by the confirmation of localization results through successful high frequency catheter ablation.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the non-invasive localization accuracy of cardiac arrhythmias attainable by multichannel magnetocardiography (MCG)

et al. 1996

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The accuracy of multichannel magnetocardiography (MCG) for the non-invasive localization of cardiac arrhythmias was investigated. A non-magnetic catheter was used in phantom studies and for cardiac pacing of 6 patients. In a clinical setting, 32 patients with WPW-syndrome, 37 patients with premature ventricular complexes and 12 patients with ventricular tachycardia were studied and the MCG results compared to reference methods, including invasive electrophysiological mapping. Phantom and pacing studies demonstrated the spatial localization accuracy to be better than 15 mm for a dipole-to-dewar distance below 15 cm. In all patients with structural cardiac disease, the ectopic focus was localized at the margin of the damaged area, serving as a proof of MCG localization. Invasive mapping confirmed the MCG result whenever performed (42 patients). In 11 patients (9 WPW, 2 VT) the MCG localization result was verified by successful HF catheter ablation as a gold standard. MCG permits the non-invasive localization of cardiac arrhythmias with high spatial accuracy. MCG guided HF catheter ablation constitutes a new concept of non-invasive localization and minimally invasive causal therapy.

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“…The technical details are described elsewhere [9]. The essential features of the equipment are: -Magnetocardiograph and patient within a magnetically shielded room (two layers of soft magnetic material with one layer of aluminium in between) -Multichannel sensor with 37 gradiometers equally distributed over a disk of 19 cm in diameter linked to SQUIDs -Recording of magnetocardiograms, electrocardiograms and respiratory cycles simultaneously -Calculation of the site of abnormal ventricular excitation [10] by approximating the human chest as a homogeneous infinite half space, the equivalent current dipole (ECD) is found in a non-linear optimization procedure by minimizing the difference between the measured and calculated magnetic field distribution (field maps) -Site of dipole depicted in 1ms intervals in the frontal and axial plane -Anatomic localization of the calculated site of the current dipole by magnetic resonance imaging (MRI), using four anatomically defined markers on the surface of the thorax -Improvement of source localization in WPW patients by subtraction of atrial background activity by adaptive subtraction of the slowly changing magnetic field of the atria…”

Section: Double Angulated Ispect (Da-ispect)mentioning

confidence: 99%

Localization of ectopic ventricular depolarization by ISPECT-radionuclide ventriculography and by magnetocardiography

et al. 1991

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Since catheter or surgical techniques for ablating the arrhythmogenic substrate in patients with SVT due to accessory pathways or those with VT are now available, exact localization of the substrate is mandatory. We report preliminary results of two new non-invasive techniques for localizing either the site of earliest ventricular contraction using ISPECT, or the site of initial ventricular depolarization by magnetocardiography (MCG) in WPW syndrome and in VT patients. Thirteen patients with WPW syndrome and 8 patients with sustained VTs were studied with ISPECT. In 9/13, comparative catheter mapping data were available. Two patients had two Kent bundles. 13/15 Kent bundles could be localized by ISPECT. In 5/9 patients the area of Kent bundle insertion was identical with ISPECT and catheter mapping, in 3 correlation was fair, and in 2 patients with 2 Kent bundles ISPECT failed to localize their insertion. In 3/8 patients with VT catheter mapping could not be performed for hemodynamic reasons. In 2/5 patients the area of VT focus was identical with both methods, in one patient it was adjacent to each other, and in 2/5 patients a larger anatomic distance of the focus was found with both methods. In 3/7 patients with WPW the MCG showed the site of Kent bundle insertion, which was identical to that seen by catheter mapping. In one patient the area was adjacent, and in 3 more distant from the site determined by catheter mapping. In 1/2 patients with 2 Kent bundles, one of these could be detected by MCG. In 1/3 patients with VT, the site of VT focus was identical with both methods, but in the remaining two a distance of 3-4 cm was observed between the area seen with MCG and that with catheter mapping. In 4 further VT patients with stable and uniform ventricular late potentials, ventricular late magnetic activity was found with different QRS lengths within the single MCG channels. From our results we conclude that both ISPECT and MCG seem to become very promising non-invasive techniques for localizing ectopic ventricular depolarization in WPW syndrome and VT patients. However, these methods have to be refined, improved and validated by further systematical studies.

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Multichannel biomagnetic system for study of electrical activity in the brain and heart.

Cited by 72 publications

References 0 publications

Clinical magnetocardiography: Experience with a biomagnetic multichannel system

Clinical magnetocardiography: Experience with a biomagnetic multichannel system

Evaluation of the non-invasive localization accuracy of cardiac arrhythmias attainable by multichannel magnetocardiography (MCG)

Localization of ectopic ventricular depolarization by ISPECT-radionuclide ventriculography and by magnetocardiography

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