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Heart Activity Measurements Edit Varga Heart Activity Measurements Pulse rate ECG/EKG – electrocardiogram Impedance cardiogram, IKG -- impedance cardiography EchoKG – echocardiogram Magnetocardiography (MCG) Artery’s pulsation Heart Activity Measurements Pulse rate

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Heart activity measurements2 l.jpg
Heart Activity Measurements

  • Pulse rate

  • ECG/EKG – electrocardiogram

  • Impedance cardiogram, IKG -- impedance cardiography

  • EchoKG – echocardiogram

  • Magnetocardiography (MCG)

Heart Activity Measurements



Heart activity measurements4 l.jpg
Heart Activity Measurements

  • Pulse rate

  • ECG/EKG – electrocardiogram

  • Impedance cardiogram, IKG -- impedance cardiography

  • EchoKG – echocardiogram

  • Magnetocardiography (MCG)

Heart Activity Measurements


Ekg ecg electrocardiogram l.jpg
EKG/ECG -- electrocardiogram

Williem Einthoven: in 1924 Nobel prize

ECK -- electrocardiogram



Slide8 l.jpg

ATRIUM

VENTRICLE

ECK -- electrocardiogram


The conduction system of the heart l.jpg
The conduction system of the heart.

ECK -- electrocardiogram


Animation of a normal ekg wave l.jpg
Animation of a normal EKG wave

ECK -- electrocardiogram


D ifferent waveforms for each of the specialized cells found in the heart l.jpg
Different waveforms for each of the specialized cells found in the heart

ECK -- electrocardiogram


Information from ekg l.jpg
Information from EKG

  • If the electric or muscular function of the heart is disturbed for some reason, it will affect how the electric signals spread through the heart muscle.

ECK -- electrocardiogram


Slide13 l.jpg

Lead I.

Lead III.

Lead II.

ECK -- electrocardiogram


Slide14 l.jpg
EKG of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • These three bipolar limb leads roughly form an equilateral triangle (with the heart at the center) that is called Einthoven's triangle in honor of Willem Einthoven who developed the electrocardiogram in 1901.

ECK -- electrocardiogram


Negative electrode on the right arm and the positive electrode on the left arm l.jpg

Different directions during the EKG measurement of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

Negative electrode on the right arm and the positive electrode on the left arm

Negative electrode on the right arm and the positive electrode on the left leg.

Negative electrode on the left arm and the positive electrode on the left leg.

Maximal positive deflection is obtained in lead III when the depolarization wave

travels parallel to the axis between the left arm and left leg.

ECK -- electrocardiogram


Slide16 l.jpg

ECK -- electrocardiogram of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.


Slide17 l.jpg

The realtively small P of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

wave is produced by

electrical currents

generated just before

contraction of the atria

EKG

Accoustic

QRS complex is caused by

currents generated in the

ventricles during depolarization

just prior to venticular contraction.

R is the most prominent

component of this wave complex.

ECK -- electrocardiogram


Slide18 l.jpg

160 ms of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

300 ms

370 ms

ECK -- electrocardiogram

830 ms


Slide19 l.jpg

positive of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

deflection

on the ECG

negative

deflection

on the ECG

equiphasic

complex

deflection

on the ECG

External snap

Snap coated with Ag/AgCl

Gel soaked sponge

Adhesive layer

ECK -- electrocardiogram


Slide20 l.jpg

ECK -- electrocardiogram of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.


The ecg system l.jpg
The ECG system of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

Instrumentation amplifier, which has a very high CMRR (90dB) (common-mode rejection ratio)

and high gain (1000), with power supply +9V and -9V.

An opto-coupler to isolate

the In-Amp and Output.

A transducer AgCl electrode,

which convert ECG into electrical voltage.

The voltage is in the range of 1 mV ~ 5 mV

Bandpass filter of 0.04 Hz to

150 Hz filter. It’s implemented

by cascading a low-pass filter

and a high pass filter

ECK -- electrocardiogram


Heart activity measurements22 l.jpg
Heart Activity Measurements of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • Pulse rate

  • ECG/EKG – electrocardiogram

  • Impedance cardiogram, IKG -- impedance cardiography

  • EchoKG – echocardiogram

  • Magnetocardiography (MCG)

Heart Activity Measurements


Impedance cardiogram l.jpg
Impedance cardiogram of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

Impedance changes

Differentiatior

Amplifier

dZ/dt

Z0 value is the total impedance

between the two inner leads

High-frequency = 40-100 KHz

Constant current = 4 mA

Impedance cardiogram


Impedance cardiogram24 l.jpg
Impedance cardiogram of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

R-Z is the time interval from

the R wave of the ECG to

maximum ejection as indicated

by the peak of dZ/dt

ventricular ejection time

Impedance cardiogram


Slide25 l.jpg

  • Part of automated external defibrillator of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • Investigate circulatory system problems: valve defects, right-left shunting, congestive failure

  • Impedance of the thorax can be considered to be divided into two parts:

    • the impedance of both tissue and fluids

    • the amount and distribution of blood The amount of blood in the thorax changes as a function of the heart cycle. The changes in the distribution of blood in the thorax as a function of the heart cycle can be determined by measuring the impedance changes of the thorax.

Band electrodes

ECK -- electrocardiogram


Heart activity measurements26 l.jpg
Heart Activity Measurements of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • Pulse rate

  • ECG/EKG – electrocardiogram

  • Impedance cardiogram, IKG -- impedance cardiography

  • EchoKG – echocardiogram

  • Magnetocardiography (MCG)

Heart Activity Measurements


Slide27 l.jpg

EchoKG of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

Echocardiogram

Ultrasound waves: 2.5–18 MHz

EchoKG -- Echocardiogram


Slide28 l.jpg

ECK -- electrocardiogram of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.


Echokg echocardiogram l.jpg
EchoKG of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane. -- Echocardiogram

EchoKG -- Echocardiogram


Transducer l.jpg
Transducer of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

EchoKG -- Echocardiogram


40 khz ultrasound receiver l.jpg
40 kHz Ultrasound receiver of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

A X100 transistor amplifier is followed by a zero cross detector circuit, using a

voltage comparator. The output is a TTL logic signal, corresponding to the

received 40KHz signal.

ECK -- electrocardiogram


Medium power 40khz ultrasound transducer driver l.jpg
Medium Power 40KHz Ultrasound Transducer Driver of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

This crystal controlled circuit drives a 40KHz piezoelectric transducer with a 30v peak to peak signal.

ECK -- electrocardiogram


Heart activity measurements33 l.jpg
Heart Activity Measurements of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • Pulse rate

  • ECG/EKG – electrocardiogram

  • Impedance cardiogram, IKG -- impedance cardiography

  • EchoKG – echocardiogram

  • Magnetocardiography (MCG)

Heart Activity Measurements


Dc squids l.jpg
dc SQUIDs of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

Scanning electron micrograph of the SQUID ring with step-edge Josephson junctions.

  • Magnetometers based on dc SQUIDs are currently the most sensitive sensors for magnetic fields, achieving a magnetic field resolution which is about a billion times below the earth's magnetic field.

  • A dc SQUID basically consists of a superconducting ring interrupted by two weak links called Josephson junctions.

  • SQUID can be viewed as a flux-to-voltage converter.

ECK -- electrocardiogram


Noise spectrum of the magnetic field l.jpg
Noise spectrum of the magnetic field of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

noise in an industrial environment,

measured with an unshielded

multiloop magnetometer

The magnetometer's

intrinsic noise level is

several orders of magnitude lower.

ECK -- electrocardiogram


Dc squids38 l.jpg
dc SQUIDs of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

A multiloop SQUID magnetometer. The diameter of this device is 8.5 mm.

  • The SQUID ring itself is enlarged and it consists of several identical pickup loops, which are connected in parallel to reduce the inductance. The 16 loops are arranged to the cart-wheel like shape of the device. A multilayer technology is needed for the preparation.

ECK -- electrocardiogram


Block diagram of a squid magnetometer l.jpg
Block diagram of a SQUID magnetometer of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

transform the applied

flux into a room temperature

voltage output

senses changes in the

external magnetic field

and transforms them

into an electrical current

acquiring, storing

analyzing data

transforms the resulting

current into a magnetic

flux in the SQUID sensor

ECK -- electrocardiogram


68 channel dc squid system l.jpg
68-channel dc-SQUID system of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

SQUID maps the axial (BZ) component

ECK -- electrocardiogram


Real time magnetocardiogram recorded with a multiloop magnetometer l.jpg
Real-time of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane. magnetocardiogram recorded with a multiloop magnetometer.

ECK -- electrocardiogram


Magnetocardiography mcg l.jpg
Magnetocardiography of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane. (MCG)

  • Magnetic field: x, y, z component

  • Grid measurement

  • Similar sensitivity to EKG

  • Higher SNR than EKG

Magnetocardiography (MCG)


Slide43 l.jpg

magnode of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

Solenoid coil

Ir = reciprocal current

ΦLM = reciprocal magnetic scalar potential field

HLM = reciprocal magnetic field

BLM = reciprocal magnetic induction field

ELM = reciprocal electric field

JLM = lead field  

VLM = voltage in the lead due to the volume source i in the volume conductor  

Magnetocardiography (MCG)


Slide44 l.jpg

Measurement of the of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane. x-component

of the magnetic heart vector

The general construction of

the measurement system

Baule-McFee lead system

Measurement of the z-component

of the magnetic heart vector

Measurement of the y-component

of the magnetic heart vector

Magnetocardiography (MCG)


Unipolar bipolar measurement locations on the anterior and posterior sides l.jpg
Unipolar of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane. & Bipolar measurement locations on the anterior and posterior sides

ECK -- electrocardiogram


Schematic illustration of the generation of the x component of the mcg signal l.jpg
Schematic illustration of the generation of the of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane. x component of the MCG signal.

ECK -- electrocardiogram


Advantages l.jpg
Advantages of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • Insulating barriers such as the skull, varying layers of tissue, anatomical open spaces, do not attenuate or distort magnetic fields. The magnetic permeability of the tissue = free space. Therefore the sensitivity of the MCG is not affected by the high electric resistivity of lung tissue.

  • different sensitivity distribution with EKG

  • the magnetic detector is not in contact with the subject

  • SQUID magnetometer is readily capable of measuring DC signals. Such signals can be obtained electrically only with great difficulty.

Magnetocardiography (MCG)


Disadvantages l.jpg
Disadvantages of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • ECG is easier to use

  • Technologically more complicated, requires complex and expensive equipment: SQUID magnetometer, liquid helium, and a low-noise environment

  • Because of the development of the SQUID technology, a shielded room is no longer needed in magnetocardiography.

  • Future: at the liquid nitrogen temperature which decreases the operational costs

Magnetocardiography (MCG)


References l.jpg
References of the heart's depolarization wavefront (or mean electrical vector) in the frontal plane.

  • MCG:

    • http://butler.cc.tut.fi/~malmivuo/bem/bembook/20/20.htm

    • http://www.kreynet.de/asc/squids.html

  • EchoKG:

    • http://www.heartsite.com/html/echocardiogram.html#what_US

    • http://www.discovercircuits.com/DJ-Circuits/ultra40khzxtr1.htm

  • EKG

    • http://en.wikipedia.org/wiki/Electrocardiogram

    • http://www.ecglibrary.com/

    • http://www.americanheart.org/presenter.jhtml?identifier=3005172

    • http://www.medmovie.com/mmdatabase/MediaPlayer.aspx?ClientID=68&TopicID=600

    • John L. Andreassi: Psychophysiology

    • http://www.cisl.columbia.edu/kinget_group/student_projects/ECG%20Report/E6001%20ECG%20final%20report.htm


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