Download electrocardiogram (ecg)

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Heart failure wikipedia , lookup

Cardiac surgery wikipedia , lookup

Cardiac contractility modulation wikipedia , lookup

Myocardial infarction wikipedia , lookup

Arrhythmogenic right ventricular dysplasia wikipedia , lookup

Atrial fibrillation wikipedia , lookup

Heart arrhythmia wikipedia , lookup

Electrocardiography wikipedia , lookup

Transcript
‫بسم هللا الرحمن الرحيم‬
Cardiovascular System (CVS 227)
ELECTROCARDIOGRAM (ECG)
BASIC PRINICPLES
Dr.Mohammed Sharique Ahmed Quadri
Asst. professor in physiology
Al Maarefa College
1
2
CONDUCTION SYSTEM OF THE HEART
3
PRINCIPLE OF RECORDING ECG
The body is a good conductor of electricity
Battery
4
ELECTROCARDIOGRAM

Electrocardiogram:
Measure of the electrical activity of the heart per unit
time.
 Potential
differences generated by heart are conducted
to body surface where they can be recorded on
electrodes on the skin.

Does NOT measure the flow of blood through the
heart.

Electrocardiograph : device that records the electrical
activity of the heart
5
ELECTROCARDIOGRAPH
6
ECG
What is Lead?
 ECG recorded on the paper after putting the
electrode.

What is Electrode?
 It is a metallic plate which conducts electricity.

7
LEADS ARE LIKE PICTURES OF THE HEART
8
LEADS ARE LIKE PICTURES OF THE HEART
9
BE CAREFUL !! DON’T PUT WRONG LEADS
10
STANDARD 12-LEAD ELECTROCARDIOGRAM

Six Limb Leads :
Frontal plane currents (right, left, inferior, superior)
 Three Bipolar Limb Leads( standard limb leads)
 named
 Three


as , I, II , III
Unipolar Limb Leads ( augmented limb leads)
named as aVR, aVL, aVF
Six precordial (chest) leads
Horizontal plane (anterior, posterior, right and left
forces)
11
BIPOLAR / STANDARD LIMB LEADS
Record the electrical potential difference in the
frontal plane
 In bipolar lead, we record potential difference
between two active electrodes.

12
UNIPOLAR (AUGMENTED) LEADS
Record electrical potential in the frontal
plane
 In Unipolar lead, we record potential
difference between active electrode and
other electrode at zero potential.

13
EINTHOVEN’S TRIANGLE
The axis of the limb
leads form an
equilateral triangle
around the heart’s
electrical field
14
PRECORDIAL (CHEST) LEADS
15
HEART IN THREE DIMENSION
16
ELECTRODES & WAVES
If current is flowing towards the recording electrode,
we get upward deflection.
If current is flowing away from the recording
electrode, we get downward deflection.
17
Standard 12 Lead ECG
18
THE ECG PAPER

Horizontally
 One
small box - 0.04 s
 One large box - 0.20 s

1mm
Vertically
 One
large box - 0.5 mV
19
BASIC COMPONENTS

Waves

Segments & intervals
20
BASIC COMPONENTS
NORMAL IMPULSE CONDUCTION
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
22
IMPULSE CONDUCTION & THE ECG
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
23
THE “PQRST”
• P wave - Atrial
Depolarization
• QRS - Ventricular
Depolarization
• T wave - Ventricular
Repolarization
24
THE PR INTERVAL
Atrial depolarization
+
delay in AV junction
(AV node/Bundle of His)
(delay allows time for
the atria to contract
before the ventricles
contract)
25
SEGMENTS & INTERVALS

PR interval: 0.12 – 0.20 sec

QRS interval : 0.08 – 0.10sec

QT interval : 0.40-0.43sec

ST interval :0.32 - sec
26
THE ELCTRICAL AXIS OF THE HEART

Vector is diagrammatic way to show strength &
direction of impulse
27
MEAN ELECTRICAL AXIS

Is some total of all
vectors generated by
the action potential of
individual ventricular
myocytes.

we measure the way
the vectors looks as it
travels under each of
various electrode
28
MEAN ELECTRICAL AXIS OF THE HEART:
QRS AXIS

Normal range
29
Axis
Determination of Mean Electrical
The QRS axis is determined by overlying a circle, in the frontal
plane. By convention, the degrees of the circle are as shown.
The normal QRS axis lies between -30o and +110o.
A QRS axis that falls between -30o
and -90o is abnormal and called left
axis deviation.
-90o
-60o
-120o
-150o
A QRS axis that falls between
+110o and +180o is abnormal and
called right axis deviation.
-30o
180o
o
A QRS axis that falls between +180
and -90o is abnormal and called
Indeterminant (extende rt axis ) .
0o
30o
150o
120o
90o
60o
REFERENCES

Text book of medical physiology by GUYTON &
HALL 11th edition

Text book physiology by GANONG

The ECG made Easy by John R.Hampton sixth
edition
31