Download Methodical instructions (indication)

"Affirmed"
At methodical session of the chair of medical
and biological physics
2007. The report №
chief of chair
Shaplavskij M.V.
Methodical instructions (indication)
for plan students self- preparation
“The physical basis of electrocardiography”
Module 2: Basic regularities of biomechanics and electricity and use of them in
medical diagnostic and treatment
Pithy module 5. Electrical properties of cells, tissue, organs and methods of
fixation of medical and biological information
Chernivtsi-2007
Objective: To Study find derivative to function and to can her apply attached to decision of
medical-biological tasks.
Introduction:
Derivative functions one of basic notions of higher mathematics. On base of this notion can
be calculated basic flowing descriptions of different medical-biological processes, in particular
flowing speeds of these processes /bacterium reproduction speed, blowing speed about bacterium,
diffusion speed of infectious disease/.
Background:
1. Notion of function.
2. Function. Border and regulations of her finding.
3. Basic elementary functions /sedate, model, logarithmic, trigonometrical functions their basic
properties and graphs.
Basic question:
1. Determination of function and derivative function.
2. Physical and geometrical maintenance derivative.
Practical exercise:
1. To analyze the basic typical tasks on finding derivative and to learn a methods of
their decision.
2. To find derivative functions, which offer by teacher /as attached to decision on
board
so
and
independently
to
clear
up
herewith
the
incomprehensible
questions
and decisions receptions and to clear up them by the medium of teacher.
Final knolege and skills:
Students should know:
1. Governed finding derivative of basic functions.
2. Governed finding of derivative sum, work, particle and complicated function.
Students should be able:
1. To Find derivative functions.
2. To Apply derivative for finding of speed flowing different processes.
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Contents of theme
1. Electrophysiology.
2. Heart.
3. Bioelectricity of the heart.
1) Cardiac cells;
2) Cardiac muscle;
3) Cardiac action potentials
4) The heart's electrical conduction system;
5) Peculiarities of the heart's electrical conduction system;
6) Electrical behavior of the heart
4. The physical basis of electrocardiography.
5. Source models.
6. Einthoven's electrocardiographic model.
Literature
1. Raymond A.Serway, Jerry S. Faughn Colloge physics, Fifth Edition.-Saunders College
Publishing.- 1999.-1029 p.
2. Marzeniuk V.P., Diduch V.D., Vakulenko D.V. et al. Biophysics and medical informatics.Ternopil: Ukrmedkniha, 2004.-480p.
3. Hugh D. Young, Roger A. Freedman University physics with modern physics, 11 th edition.Pearson education.-2004.-1714p.
4.Frank J. Blatt Modern Physics .-McGRAW-HILL, INC.-1992.- 517 p.
5. Methodical instructions (indication) for student’s preparation, lecture.
Questions for self-preparation of students:
1.What is electrophysiology?
2.Bioelectricity of the heart (cardiac cells, cardiac muscle, cardiac action potentials,
3.The heart's electrical conduction system
4.The physical basis of electrocardiography
5.Source models
6.Einthoven's electrocardiographic model
Tests.
1. One of thesises of Endhoven’s theory consist in that proections of electrical vector of
heart on equilateral triangle of Endhoven are:
a.
b.
c.
d.
quadratic
inversely proportional
proportional
exponentional
to corresponding difference
potential (voltage) in tree
standart leads
2. Choose right unique characteristics of cardiac electrical cells:
a) automaticity ; b) conductivity; c) contractility; d) excitability; e)
3 An electrical stimulus is generated:
a. by the sinus node
b. by the atrioventricular node
c. by the bundle of His
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Class independent work
A cardiac vector is a diagnostic measure that has the properties of representing the direction
and magnitude of electrical current moving across and within the heart at any moment in time. Any
two of the three leads can be used to determine the cardiac vector. The most common technique
for this calculation involves the use of Einthoven's Triangle:
a. Construct an equilateral triangle with a point directed down (as below). Each corner
represents one of the electrode positions (right arm, left arm, lower left abdomen; compare the
figure with table above). Each side represents the recording electrodes for each of the three “lead”
orientations. For example, the left arm and right arm are the two recording electrodes for lead I; the
side of the triangle between them represents lead I in Einthoven’s triangle.
b. Draw perpendicular lines from the center of each side to determine the geometric center of
the triangle (dotted lines).
For two of the three leads (usually Lead I and Lead III), calculate the "resultant deflection"
For each of the two resultant deflections determined (e.g. Lead I and Lead III), draw a line
proportional in length to the resultant deflections. If the sign of the resultant deflection is
POSITIVE, direct the arrow towards the corner of the triangle representing the POSITIVE electrode
for that lead; vice versa if the resultant deflection has a negative sign.
c.
d.
Draw a second pair of lines. These are perpendicular to the baseline of each Lead's trace
and extend toward the inside of the triangle.
e.
f.
g.
These two lines will intersect somewhere inside the triangle.
The cardiac vector extends from the center of the triangle to this intersection point.
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This arrow is a representation of the direction (θ) and intensity (in mV) of combined electrical
activity present in the heart at that moment.
Voltages measured by the three limb leads are proportional to the projections of the
electric heart vector on the sides of the lead vector triangle
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