ECG.ppt in this ppt heart rate rhythm, ecg waves all can study

mrs.nagarani
medical -surgical nursing dept

1. ELECTROCARDIOGRAM
BY
MRS. NAGARANI
M.SC NURSING
MEDICAL-SURGICAL NURSING

2. ECG
INTTRPRETATION

3. OBJECTIVES
After completion of session participants will be able to
Introduce the ECG interpretation
Define ECG interpretation
Explain about obtaining the ECG
Explain about the ECG interpretation
Explain about the waves, complex, interval and
segments
Explain the strategies to determine the heart rate and
rhythm from ECG

4. INTRODUCTIONINTRODUCTION
It is a process of recording the electrical
activity of the heart over a period of
time using the electrodes placed on the
skin.
It is a test that checks the problems with
the electrical activity of the heart.
It show the electrical activity of the
heart a line tracing on the paper
Waves: the spikes and dips in the
tracing are called the waves.

6. Obtaining an ECG
Electrodes are attach to cable wires which are
connected to one of the following
ECG monitor
Cardiac monitor
Telemetry
Ambulatory ECG monitor or Holter monitor

7. Cardiac telemetry
Cardiac telemetry monitoring is
a way to get facts about your
heart's electrical activity
continuously in a hospital's
cardiac telemetry unit.
 It collects data from a device
that uses electrodes a healthcare
provider sticks on your chest.
Providers can look at the
readings to find abnormal heart
rhythms (arrhythmias).

9. For a standard 12 lead ECG
10 electrodes ( 6 on the chest and 4 on the
limbs )are placed on the body.
To prevent inference from electrical
activity of the skeletal muscle, limbs
electrodes are usually placed on the areas that
not bony and don’t have any significant
movement.
These limb electrodes provide the first 6
leads –lead I,II,III or aVR, aVL, aVF.
Six chest electrodes are applied to the chest
at a very specific area.
Provide the v or precordial leads, V1 to V6
Obtaining an
ECG

10. There are 3 sets of leads
•Standard limb or bipolar le
ads (I,II,III) Utilize three el
ectrodes these leads from a
triangle known as Einthove
n's triangle.
•Augmented unipolar leads
(aVr, aVl, aVf)
•Precordial unipolar leads
(V1, V2,V3,V4,V5,V6)

14. Einthoven’s law
Einthoven's triangle is
 an imaginary
triangle formed by three electrodes
placed on the chest to record the
heart's electrical activity.
 It's used in
electrocardiograms (ECGs) to
measure the heart's potential
difference.
 

15. Explanation
The triangle is formed by the shoulders and the
pubic symphysis.
 
The heart is at the center of the triangle. 
The triangle is made up of three leads: lead I, lead
II, and lead III.
 
The leads are placed on the right arm, left arm,
and left leg.
 
The information gathered between the leads is
called "bipolar".
 
The triangle is named after Willem Einthoven, the
Dutch doctor who invented the first ECG in
1895 . 

16. How it's used
 
•The triangle is used to measure the
heart's potential difference.
•The triangle is used to record
heartbeats
•The triangle is used to determine the
electric axis of the heart.

19. Heart structure
The heart is made up of four
chambers:
two upper chambers known
as the left atrium and right
atrium and two lower
chambers called the left and
right ventricles.
It is also made up of four
valves: the tricuspid,
pulmonary, mitral and aortic
valves.

20. Layers of the heart
The heart has three layers:
The endocardium, myocardium,
and epicardium.
The heart also has a fourth layer
called the pericardium, which
surrounds the heart.

22. The heart's conduction
system is a network of
specialized muscle cells
that sends electrical
signals throughout the
heart.
 These signals determine
the timing of the
heartbeat.

24. INTERPRETION
OF ECG
RATE
RYTHAM
AXIS
P WAVES
PR INTERVAL
QRS
ST SEGMENT
T WAVES
QT INTERVAL
RR INTERVAL

25. HEART RATE
Normal Heart Rate Is 72b/m

Normal range of heart rate is 60-100
b/m
Bradycardia < 60b/m
Tachycardia>100b/m
How to calculate heart rate :
1.QRS complex x 6=BPM
2.Rate =60/(R-R interval time)
3.Rate =300(# of large boxes
between R-R interval

26. INTERPRETING
THE ECG
ECG waveforms reflects the function of the heart conduction systeECG waveforms reflects the function of the heart conduction syste
m which normally initiate and conduct the electrical activity.m which normally initiate and conduct the electrical activity.
Wave are printed on the graph paper that is divided by light and d
ark vertical and horizontal lines at standard interval.
Time and rate are measured on the horizontal x axis of the graph,
and voltage is measured on the vertical Y axis.
When an ECG waveforms moves towards the top of the paper. It i
s called a positive deflection.
When an ECG waveforms moves towards the bottom of the paper.
It is called a negative deflection.

28. ECG INTERPETATION

29. PQRST WAVE
P WAVE= Atrial Depolarization
QRS COMPLEX= Ventricular Depolariza
tion
T WAVE =Ventricular Repolarization
U WAVE =Purkinje Fiber Repolarization

30. Segments & Interval
PR interval
ST segment
QT interval
TP interval
PP interval
RR interval

32. P WAVE
It represent the atrial depolarization
It arise when the impulse from the SA
node over the atria.
Atrial depolarization is
 the electrical
activation of the atria, which are the
upper chambers of the heart.
 It's the
process that causes the atria to contract,
which pumps blood into the ventricles. 
It is normally 2.5mm or less than 0.11
seconds or less than duration

33. QRS complex
QRS complex is represents
ventricular depolarization
Ventricular depolarization
is
 the electrical activation of
the ventricles of the heart,
which causes them to
contract.
 It's represented on an
electrocardiogram (ECG) as
the QRS complex.
 
Q wave is the first negative
deflection after the P wave.
R wave is the first positive
deflection after the p wave

34. QRS complex
S wave is the first negative deflection
after the R wave.
When a wave less than 5mm in height
, small letters are used (q,r,s)
When a wave is taller than 5mm, capi
tal letters are used ( Q,R,S).
QRS complex is normally less than 0.
12 seconds in duration.

35. T wave
It represents the ventricular
repolarization (resting stage) or
relaxation of ventricular muscle.
Atrial repolarization is also occurs
but not visible on ECG because of
it is occurs at the same time as the
QRS or ventricular depolarization.

36. U wave
The depolarization of Purkinje fibers is
primarily seen as the "S wave" within the
QRS complex on an ECG, although the
entire complex represents the combined
depolarization of the ventricles, including
the Purkinje fibers.

37. PR INTERVAL
It measured from beginning of the p wave
to the beginning of QRS complex.
It present the time needed for sinus node
stimulation, atrial depolarization and
conducting through the AV node before
ventricle depolarization.

38. ST segment
The end of ST segment is very difficulty to
identify because it merge into the T wave.
The ST segment is normally iso-electric.
It is analysed to identify whether it is above
or below the iso-electric line which may be
sign of cardiac ischemia.

39. St segment
It measured from the end of the QRS complex to the beginning of
T wave.
It represents the early ventricular depolarization
The ST segment on an electrocardiogram (ECG)represents
 the
period between the end of ventricular depolarization and the
beginning of ventricular repolarization.
 
Normal ST segment: A flat line that's isoelectric, meaning it's
neither positive nor negative.

40. Qt interval
It represents the time required for
the ventricular depolarization and
repolarization.
It measured from the beginning of
QRS complex to the end of T wave.
QT interval is usually 0.32 -0.42
second in duration. If the heart rate
is 65-90 b/m.

41. Qt interval
It varies according to the heart rate,
gender and age, measured interval need
to be corrected for these variable through
specific calculation.
If the QT interval become prolonged, the
patient may be at risk for lethal
ventricular dysrhythmias called the
torsade's de points.
 a pattern of twisting QRS complexes.
 
It's characterized by a prolonged QT
interval, which is the time between the
QRS complex and the T wave on an
ECG

42. Tp interval
It measured from the end of the T
wave to the beginning of the next
P waves , an iso-electric period.
When no electrical activity is
detected, the line on the graph
remains flats, this called iso-
electric line.

43. PP interval
It measured from the
beginning of P wave to
the beginning of next
P wave.
It is used to determine
the atrial rhythm and
rate.

44. RR interval
It measured from the o
ne QRS complex to the
next QRS complex.
It is used to determine t
he ventricular rhythm a
nd rate

45. DETERMINIG
THE HEART RATE FROM ECG
It can be obtained from the ECG strip by
several methods.
1 minute strip contain 300 large box and
1500 small boxes.
An easy and accurate method to determine
the heart rate with a regular rhythm is to
count the number of small boxes within an
RR interval and divide 1500 by that number.
EXAMPLE: 22 small boxes between the R
waves. The heart rate is 1500/21 heart rate
71b/m

46. An alternate and less
accurate method for
estimating the heart rate,
which is used when the
sinus rhythm is irregular
is to count the number of
RR interval in 6 seconds
and multiply by the 10.
6x10=60 b/m

47. DETERMINING
THE HEART RHYTHAM FROM ECG
Rhythm is defined at the same time, heart
rate is determined.
The PP interval is used to determine the
atrial rhythm.
The RR interval is used to determine the
ventricular rhythm.
To determine the atrial rate, count the
number of P waves in 6 second and multiply
by 10 to obtain full heart rate Eg:
7X10=70B/M

48. To determine the ventricles rate,coun
t the number of R& QRS waves in 6
second and multiply by 10 to obtain f
ull heart rate Eg:7x10=70b/m
If the interval are the same or if the di
fference between the interval is less t
han the 0.8 second throughout the stri
p, the rhythm is called regular.
If the interval is difference, the rhyth
m is called irregular.

49. NORMAL ECG

52. Sinus rhythm

53. Tachycardia

54. Bradycardia

55. Ventricular tachycardia

56. Atrial fibrillation

57. Right bundle branch block

59. Heart block

60. Myocardial infraction

61. Cardiac asystole