Apparatus and Method for Measuring Electric Non-Contact Electrocardiogram in Everyday Life

• US 20070255152A1
• Filed: 08/31/2005
• Published: 11/01/2007
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Seoul National University Industry Foundation (Seoul National University)
• Original Assignee: Seoul National University Industry Foundation (Seoul National University)
• Inventors: Park, Kwang-Suk, Lim, Yong-Kyu, Kim, Ko-Keun
• Granted Patent: US 7,684,854 B2
• Time in Patent Office: Days
• US Class Current: 600/513
• CPC Class Codes: A61B 5/28 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices
• CPC Class Codes: A61B 5/6892 Mats

Abstract

The present invention relates generally to an electric non-contact apparatus and method for taking electrocardiograms and, more particularly, to an electric non-contact apparatus and method for taking electrocardiograms, in which an examinee can have an electrocardiogram taken in a comfortable position because the apparatus and method are applied to a chair, a bed or a vehicle seat, which are widely used in daily life, and in which the examinee can unnoticeably have an electrocardiogram taken without being conscious of the taking of the electrocardiogram because the taking of the electrocardiogram is performed on the body of a human wearing clothes without directly contacting the body.

Claims

1. An apparatus for taking ElectroCardioGrams (ECGs), the apparatus being attached to a human body, comprising:

one or more amplifier-attached electrodes (10) installed adjacent to appropriate locations of clothes (5) without directly contacting a body (3);

one or more filter and amplifier units (30) connected to first sides of the amplifier-attached electrodes (10) and configured to filter out external noise and amplify filtered signals;

one or more Analog/Digital (A/D) converters (50) connected to first sides of the filter and amplifier units (30);

a digital signal processing unit (70) provided to first sides of the A/D converter (50) and configured to transmit a taken ECG to a display and a post-processing device; and

a ground plate (80) installed adjacent to an appropriate location on the clothes (5) without directly contacting the body (3).

2. The apparatus as set forth in claim 1, wherein each of the amplifier-attached electrodes (10) comprises an electrode face (11) provided on one side of the amplifier-attached electrode (10), a preamplifier (13) for amplifying and impedance-converting a biosignal input through the electrode face (11), and a shield (15) provided around the preamplifier (13).

3. The apparatus as set forth in claim 1, wherein each of the filter and amplifier units (30) comprises a high pass filter circuit (31) for filtering out variation of offset accompanying the biosignal input to the preamplifier (13) of the amplifier-attached electrode (10) in displacement current form, a band stop filter circuit (33) for filtering out 60 Hz band common-mode noise from a biosignal input through the high pass filter circuit (31), an amplification circuit (35) for amplifying a biosignal, which is input through the band stop filter circuit (33), at a predetermined amplification ratio, and a low pass filter circuit (37) for extracting a low band signal of 100 Hz or lower frequency from a biosignal input through the amplification circuit (35) and outputting the lower band signal as an analog signal.

4. The apparatus as set forth in claim 1, wherein each of the A/D converters (50) is configured to convert the biosignal-based analog signal, which is input through the filter and amplifier unit 30, into a digital signal.

5. The apparatus as set forth in claim 1, wherein the digital signal processing unit (70) comprises a subtractor (71) for obtaining a difference between the digitized biosignals input through the A/D converters (50), and a subtraction filter (73) for filtering out noise, which is generated during the subtraction, from the digital signals input through the subtractor (71).

6. The apparatus as set forth in any one of claims 1 to 5, wherein, when the electric non-contact ECG apparatus (1) is applied to a chair (91),

the amplifier-attached electrodes (10) are installed on appropriate sides of a backrest part (97) of the chair (91) on which both shoulders of an examinee are placed, and the ground plate (80) is installed at a predetermined location on a seat part (99) of the chair (91) on which buttocks of the examinee are placed.

7. The apparatus as set forth in any one of claims 1 to 5, wherein, when the electric non-contact ECG apparatus (1) is applied to a chair (91),

the amplifier-attached electrodes (10) are installed on appropriate sides of a seat part (99) of the chair (91) where both thighs of an examinee are placed, and the ground plate (80) is installed at a predetermined location on a backrest part (97) of the chair (91) on which both shoulders of the examinee are placed.

8. The apparatus as set forth in any one of claims 1 to 5, wherein, when the electric non-contact ECG apparatus (1) is applied to a bed (93),

the amplifier-attached electrodes (10) are installed on a first side of an upper surface of a mattress of the bed (93) on which both shoulders of an examinee are placed, and the ground plate (80) is installed on a second side of the upper surface of the mattress of the bed (93) on which buttocks of the examinee are placed.

9. The apparatus as set forth in any one of claims 1 to 5, wherein, when the electric non-contact ECG apparatus (1) is applied to a bed (93),

the amplifier-attached electrodes (10) are installed on a first side of an upper surface of a mattress of the bed (93) on which thighs of an examinee are placed, and the ground plate (80) is installed on a second side of the upper surface of the mattress of the bed (93) on which both shoulders of the examinee are placed.

10. The apparatus as set forth in any one of claims 1 to 5, wherein, when the electric non-contact ECG apparatus (1) is applied to a driver'"'"'s seat of a vehicle,

the amplifier-attached electrodes (10) are installed on appropriate sides of a steering wheel (96), which is provided in front of the driver'"'"'s chair and is used to steer the vehicle, to enable direct contact, and the ground plate (80) is installed at a predetermined location on a seat part (99) of the driver'"'"'s seat (95).

11. The apparatus as set forth in any one of claims 1 to 5, wherein, when the electric non-contact ECG apparatus (1) is applied to a driver'"'"'s seat of a vehicle,

the amplifier-attached electrodes (10) are installed on appropriate sides of a seat part (99) of the driver'"'"'s seat (95) where thighs of a driver are placed, and the ground plate (80) is installed on a steering wheel (96), which is provided in front of the driver'"'"'s chair and is used to steer the vehicle, to enable direct contact.

12. A method of taking ECGs of examinees based on an ECG apparatus (1), the ECG apparatus (1) having one or more amplifier-attached electrodes (10), one or more filter and amplifier units (30), one or more A/D converters (50), a digital signal processing unit (70) and a ground plate (80), comprising:

the step (S1) at which biosignals, which are generated in an examiner'"'"'s body (3), are input to the amplifier-attached electrodes (10) across worn clothes (5) via displacement current;

the step (S2) at which the input biosignals are amplified and impedance-converted by the amplifier-attached electrodes (10);

the step (S3) at which the biosignals, which are converted by the amplifier-attached electrodes (10), are input to the filter and amplifier units (30);

the step (S4) at which the input biosignals are filtered and amplified by the filter and amplifier units (30);

the step (S5) at which biosignal-based analog signals, which are output from the filter and amplifier units (30), are input to the A/D converters (50);

the step (S6) at which the biosignal-based analog signals are converted into digital signals by the A/D converters (50);

the step (S7) at which the digital signals, which are obtained by the A/D converters (50), are input to the digital signal processing unit (70); and

the step (S8) at which an ECG, on which subtraction and filtering are performed by the digital signal processing unit (70), is displayed on a display.

13. The method as set forth in claim 12, wherein the biosignals input to the amplifier-attached electrodes (10) are detected by electrode faces (11) and the biosignals are amplified and impedance-converted by preamplifiers (13).

14. The method as set forth in claim 12, wherein variation of offset is eliminated and filtered out from the biosignals, which are input to the amplifier-attached electrodes (10), by high pass filter circuits (31), 60 Hz band common-mode noise passed through the high pass filter circuit (31) is eliminated and filtered out by a low pass filter circuit (37), the biosignals passed through the low pass filter circuit (37) are amplified at a predetermined amplification ratio by an amplification circuit (35), and the amplified biosignals amplified by the amplification circuit (35) are output as analog signals in a low signal band.

15. The method as set forth in claim 12, wherein the digital signals input to the digital signal processing unit (70) are subtracted by the subtractor (71), and noise, which is generated during the subtraction through the subtractor (71), is eliminated by a subtraction filter (73).

16. The method as set forth in claim 12, wherein the ground plate (80) eliminates common-mode noise of the body in such a way as to detect the common-mode noise by performing subtraction and addition on the signals input from the amplifier-attached electrodes (10), and connect to the amplifier-attached electrodes (10) in a negative feedback fashion.