Magnetic measurements of cardiac mechanical activity

Roman Maniewski; Toivo Katila; Torsti Poutanen; Pentti Siltanen; Timo Varpula; John Wikswo

doi:10.1109/10.7267

Magnetic measurements of cardiac mechanical activity

Roman Maniewski, Toivo Katila, Torsti Poutanen, Pentti Siltanen, Timo Varpula, John Wikswo

VTT Technical Research Centre of Finland

Research output: Contribution to journal › Article › Scientific › peer-review

4 Citations (Scopus)

Abstract

The origin of the magnetic susceptibility signal caused by mechanical activity of the heart is studied. Magnetic signals were measured with a second order SQUID (superconductor quantum interface device) gradiometer by applying a homogeneous external magnetic field with magnitude up to 260 A/m. Three experimental methods were used to separate the different components in the magnetic susceptibility signal. First, the thorax of the subject was surrounded by water solution of MnCl₂ with various magnetic susceptibilities, then a plastic bag containing a similar solution was placed on the chest of the subject, and finally the chest wall of the subject was immobilized during the measurements by using a special vacuum casting. The results suggest that usually about 65-80% of the signal measured near the heart originates directly from cardiac volume changes.
This cardiac plethysmogram can be separated easily by immobilizing the subject's chest or by surrounding the chest with the liquid, whose magnetic susceptibility is about -5*10^-6.

Original language	English
Pages (from-to)	662-670
Journal	IEEE Transactions on Biomedical Engineering
Volume	35
Issue number	9
DOIs	https://doi.org/10.1109/10.7267
Publication status	Published - 1988
MoE publication type	A1 Journal article-refereed

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title = "Magnetic measurements of cardiac mechanical activity",

abstract = "The origin of the magnetic susceptibility signal caused by mechanical activity of the heart is studied. Magnetic signals were measured with a second order SQUID (superconductor quantum interface device) gradiometer by applying a homogeneous external magnetic field with magnitude up to 260 A/m. Three experimental methods were used to separate the different components in the magnetic susceptibility signal. First, the thorax of the subject was surrounded by water solution of MnCl2 with various magnetic susceptibilities, then a plastic bag containing a similar solution was placed on the chest of the subject, and finally the chest wall of the subject was immobilized during the measurements by using a special vacuum casting. The results suggest that usually about 65-80% of the signal measured near the heart originates directly from cardiac volume changes. This cardiac plethysmogram can be separated easily by immobilizing the subject's chest or by surrounding the chest with the liquid, whose magnetic susceptibility is about -5*10-6.",

author = "Roman Maniewski and Toivo Katila and Torsti Poutanen and Pentti Siltanen and Timo Varpula and John Wikswo",

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doi = "10.1109/10.7267",

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T1 - Magnetic measurements of cardiac mechanical activity

AU - Maniewski, Roman

AU - Katila, Toivo

AU - Poutanen, Torsti

AU - Siltanen, Pentti

AU - Varpula, Timo

AU - Wikswo, John

PY - 1988

Y1 - 1988

N2 - The origin of the magnetic susceptibility signal caused by mechanical activity of the heart is studied. Magnetic signals were measured with a second order SQUID (superconductor quantum interface device) gradiometer by applying a homogeneous external magnetic field with magnitude up to 260 A/m. Three experimental methods were used to separate the different components in the magnetic susceptibility signal. First, the thorax of the subject was surrounded by water solution of MnCl2 with various magnetic susceptibilities, then a plastic bag containing a similar solution was placed on the chest of the subject, and finally the chest wall of the subject was immobilized during the measurements by using a special vacuum casting. The results suggest that usually about 65-80% of the signal measured near the heart originates directly from cardiac volume changes. This cardiac plethysmogram can be separated easily by immobilizing the subject's chest or by surrounding the chest with the liquid, whose magnetic susceptibility is about -5*10-6.

AB - The origin of the magnetic susceptibility signal caused by mechanical activity of the heart is studied. Magnetic signals were measured with a second order SQUID (superconductor quantum interface device) gradiometer by applying a homogeneous external magnetic field with magnitude up to 260 A/m. Three experimental methods were used to separate the different components in the magnetic susceptibility signal. First, the thorax of the subject was surrounded by water solution of MnCl2 with various magnetic susceptibilities, then a plastic bag containing a similar solution was placed on the chest of the subject, and finally the chest wall of the subject was immobilized during the measurements by using a special vacuum casting. The results suggest that usually about 65-80% of the signal measured near the heart originates directly from cardiac volume changes. This cardiac plethysmogram can be separated easily by immobilizing the subject's chest or by surrounding the chest with the liquid, whose magnetic susceptibility is about -5*10-6.

U2 - 10.1109/10.7267

DO - 10.1109/10.7267

M3 - Article

SN - 0018-9294

VL - 35

SP - 662

EP - 670

JO - IEEE Transactions on Biomedical Engineering

JF - IEEE Transactions on Biomedical Engineering

IS - 9

ER -

Magnetic measurements of cardiac mechanical activity

Abstract

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