Document Detail


Two-dimensional mapping of impedance magnetocardiograms.
MedLine Citation:
PMID:  12083307     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A new method for measuring two-dimensional (2-D) impedance magnetocardiograms (I-MCGs) and magnetocardiograms (MCGs) above the heart simultaneously, has been developed. The I-MCG's and MCG's signals are recorded by using a superconducting interference device (SQUID) system. To measure the I-MCG and MCG signals, four first-order gradiometers with an 18-mm diameter and a 50-mm baseline were used. The SQUIDs are driven by a flux-locked-loop circuit with a frequency range higher than that of an ac-current (40 kHz) with constant amplitude passed through a subject. The output of the circuit is filtered through two circuits: one for measuring the I-MCG signals and one for measuring the MCG signals. The I-MCG signals are obtained by demodulating the magnetic field, which is detected by the gradiometers, at the frequency of the ac current. As a result, the I-MCG signal reflects the change in spatial distribution of conductivity caused by the movement of the heart muscle and blood volume. A contour map of the 2-D I-MCG signals showed the largest signals occur above the right ventricle and right atrium. In a corresponding current-arrow map, it was found that the large current arrows occurred above the right side of the right ventricle. Furthermore, it was found that the systole and diastole timings obtained from the first-derivative I-MCG signal and the phonocardiogram were different. These results show that primitive 2-D I-MCG signal can provide much physiological information on the circulatory movement of the heart.
Authors:
Akihiko Kandori; Tsuyoshi Miyashita; Daisuke Suzuki; Koichi Yokosawa; Keiji Tsukada
Related Documents :
1218957 - Diode pump cochlear audition theory.
6738027 - Laryngograph as a measure of vocal fold contact area.
11014937 - A method to measure speaking time and speech sound pressure level.
23018027 - Center of pressure progression characteristics under the plantar region for elderly adu...
19169667 - An improved boussignac device for the delivery of non-invasive cpap: the super-boussignac.
3891717 - Respiratory muscle fatigue: a cause of ventilatory failure in septic shock.
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  IEEE transactions on bio-medical engineering     Volume:  49     ISSN:  0018-9294     ISO Abbreviation:  IEEE Trans Biomed Eng     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-06-26     Completed Date:  2002-08-02     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0012737     Medline TA:  IEEE Trans Biomed Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  721-8     Citation Subset:  IM    
Affiliation:
Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo, Japan. kandori@crl.hitachi.co.jp
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adult
Body Surface Potential Mapping / methods*
Carbon
Cardiac Output / physiology
Cardiography, Impedance / instrumentation*,  methods*,  statistics & numerical data
Electrodes
Humans
Image Processing, Computer-Assisted / instrumentation,  methods
Magnetic Resonance Imaging
Magnetics / diagnostic use*,  instrumentation*
Male
Models, Cardiovascular*
Phonocardiography
Sensitivity and Specificity
Chemical
Reg. No./Substance:
7440-44-0/Carbon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Quantification of 3-D field effects during 2-D microwave imaging.
Next Document:  Heart rate indication using musical data.