ECG is the recording of the electrical impulses that are generated in the heart displaying them in a wave form. It is important for health personnel to have basic knowledge regarding ECG and can be able to detect any abnormalities reflected in the ECG graph It helps to monitor the patients treatment efficacy also helps to detect any cardiac abnormalities or diseases .

1. AARATI PAHARI

2. ECTROCARDIOGRAM AND ITS BASIC
INTERPREATATION
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3. SPECIFIC OBJECTIVE
At the end of the session participants will be able to :
• define electrography .
• identify and relate waveforms to conduction system of the heart .
• explain the different lead placements in 12 lead ECG
• utilize a systematic process when approaching the interpretation of the ECG
• identify normal waveform in ECG graph
• identify common abnormalities in waveforms in ECG graph
• explain each type of artifact and how it can be eliminated
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4. ELECTROCARDIOGRAM AND CARDIAC
CONDUCTION SYSTEM
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5. HISTORY
• Willem Einthoven
(21 May 1860 – 29
September 1927)
is considered the
founder and
father of modern
ECG (1895).
Willem Einthoven (21 May 1860 – 29
September 1927) is considered the founder
and father of modern ECG (1895).
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6. INTRODUCTION
• It is the recording of the electrical impulses that are generated in the heart
displaying them in a wave form
• These impulses initiate the contraction of cardiac muscles
• Aids in diagnosis of arrhythmias and coronary artery diseases
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7. CONDUCTION SYSTEM OF HEART
Sino-atrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
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8. ECG WAVEFORMS (1/4)
Einthoven named the prominent waves alphabetically, P,Q,R, S, andT
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9. P wave
• Atrial depolarization
• Small bump upwards from the baseline
• Amplitude : 0.05 to 0.25mV (0.5 to 2.5 small boxes).
• Normal duration is 0.06-0.11 sec (1.5 to 2.5 small boxes).
PR Interval
• Interval from where the P wave begins until the beginning of
the QRS complex.
• Normal 0.12 to 0.20 seconds (3 to 5 small boxes).
ECG WAVEFORMS (2/4)
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10. ECG WAVEFORMS (3/4)
QRS complex
• Ventricular depolarization.
• End of the PR interval to the end of the S wave.
• 0.06 to 0.12 seconds (1.5 to 3 boxes).
ST segment
• Early part of ventricular repolarization
• End of the QRS complex to beginning of the T wave.
• Isoelectric line
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11. ECG WAVEFORMS (4/4)
T Wave
• Repolarization of the ventricles
U-wave
• Small upright, rounded bump.
• When observed, it follows the T-wave.
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12. LEAD PLACEMENT
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13. Introduction
• A 12 lead electrocardiogram is standard and conventional because it records the
electrical activity of the heart from 12 different views in two planes i.e frontal and
horizontal.
• Limb leads: I, II, III, aVR, aVL and aVF.
• Precordial leads: V1 to V6
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14. PRECORDIAL LEAD PLACEMENT
ELECTRODE PLACEMENT
V1 4th Intercostal space to the right of the sternum
V2 4th Intercostal space to the left of the sternum
V3 Midway between V2 and V4
V4 5th Intercostal space at the midclavicular line
V5 Anterior axillary line at the same level as V4
V6 Midaxillary line at the same level as V4 and V5
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15. LIMB LEAD PLACEMENT
ELECTRODE PLACEMENT
RL Anywhere above the right ankle and below the torso
RA Anywhere between the right shoulder and the wrist
LL Anywhere above the left ankle and below the torso
LA Anywhere between the left shoulder and the wrist
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16. LIMB LEADS
STANDARD BIPOLAR LIMB LEAD
• LEAD I
• LEAD II
• LEAD III
AGUMENTED UNIPOLAR LEAD
• aVR
• aVF
• aVL
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17. AARATI PAHARI

18. Augmented Leads
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19. BASIC INTERPRETATION OF
ELECTROCARDIOGRAM
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20. THE ECG PAPER
Horizontally
• One small box - 0.04 s
• One large box - 0.20 s
Vertically
• One large box - 0.5 mV
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21. AARATI PAHARI

22. SIX SECOND STRIP
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23. NORMAL SINUS RHYTHM
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24. STEPS OF ECG INTERPRETATION
1. Validity
2. Rhythm
3. Rate
4. P Wave
5. PR Interval
6. QRS Interval
7. T Wave
8. ST Segment
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25. 1. VALIDITY
Standardization
• Limb Lead II is mirror of aVR
• Vertical mark : two big squares(10 mm or 1mV)
• Paper speed = 25 mm/s
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26. AARATI PAHARI

27. 2. RHYTHM (1/2)
• Identify the R wave
• Lead II : rhythm lead
• Using a six second strip, measure the R to R intervals (using a scale or
markings on a pen or paper).
• Regular (are they equidistant apart)? Occasionally irregular? Regularly
irregular? Irregularly irregular
R R
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28. RHYTHM (2/2)
• If in doubt, use a paper strip to map out consecutive beats and see whether the
rate is the same
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29. 2. RATE
1. Count the no of R waves in a 6 second rhythm strip, then multiply by 10. 9 x10
=90 beats per minute
2. Count the number of small boxes for a typical R-R interval. Divide this number
into 1500 to determine heart rate
1500/15.5 = 96 beats per minute
3 sec 3 sec
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30. Rate =
For example:
300
3
1500
15
Rate =
or
Rate = 100 beats per minute
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31. For example:
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32. SINUS TACHYCARDIA
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33. SINUS BRADYCARDIA
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34. Normal P- wave
• 3 small square wide, and 2.5 small square high.
• Always positive in lead I and II in NSR
• Always negative in lead aVR in NSR
• Commonly biphasic in lead V1
3. ASSESS THE P WAVES(1/2)
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35. ASSESS THE P WAVES(2/2)
• Are there P waves?
• Do the P waves all look alike?
• Do the P waves occur at a regular rate?
• Is there one P wave before each QRS?
Normal P waves with 1 P wave for every QRS
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36. Left Atrial Enlargement
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37. 4. DETERMINE PR INTERVAL
Normal: 0.12 - 0.20 seconds.
(3 - 5 boxes)
Interpretation?
0.12 seconds
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38. (Prolonged PR Interval ) Heart Block
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39. 5. QRS DURATION
Normal: 0.04 - 0.12 seconds.
(1 - 3 boxes)
Interpretation? 0.04 seconds
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40. Narrow QRS complex (Atrial Flutter )
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41. 6. ST SEGMENT
The ST segment is the flat, isoelectric section of the ECG between the
end of the S wave and the beginning of the T wave.
ST segment depression
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42. ST segment elevation
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43. 7. T WAVE
• One fourth of R wave
• Normally >2mm in height
• >5 mm in limb leads and more than 10 mm in precordial leads
• Upright in most leads(exceptions : aVR and V1)
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44. HYPOKALEMIA
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45. NORMAL SINUS RHYTHM
PARAMETERS
• Rate 60 - 100 bpm
• Regularity regular
• P waves normal
• PR interval 0.12 - 0.20 s
• QRS duration 0.04 - 0.12 s
Any deviation from above is sinus tachycardia, sinus bradycardia or an arrhythmia
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46. RHYTHM SUMMARY
• Rate
• Regularity
• P waves
• PR interval
• QRS duration
Interpretation
• 100 bpm
• Regular
• Normal
• 0.08 s
• 0.04 sec
Normal sinus rhythm
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47. INTERPRETATION OF COMMON
ARRHYTHMIAS
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48. ATRIAL FIBRILLATION
• No organized atrial depolarization, so no normal P waves (impulses are not
originating from the sinus node).
• Atrial activity is chaotic (resulting in an irregularly irregular rate).
• Atrial rate: 300-600
• Ventricular rate: usually 120 to 200
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49. 100 bpm
• Rate?
• Regularity? irregularly irregular
none
0.06 s
• P waves?
• PR interval? none
• QRS duration?
Interpretation? Atrial Fibrillation
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50. ATRIAL FLUTTER
• No P waves. Instead flutter waves (note “sawtooth” pattern) are formed at a rate of
250 - 350 bpm.
• Ventricular rate: usually 70 to 150
• Only some impulses conduct through the AV node (usually every other impulse).
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51. 70 bpm
• Rate?
• Regularity? regular
flutter waves
0.06 s
• P waves?
• PR interval? none
• QRS duration?
Interpretation? Atrial Flutter
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52. VENTRICULAR TACHYCARDIA
• Impulse is originating in the ventricles (no P waves, wide QRS).
• Usual ventricular rate: 160 to 240
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53. 160 bpm
• Rate?
• Regularity? regular
none
wide (> 0.12 sec)
• P waves?
• PR interval? none
• QRS duration?
Interpretation? Ventricular Tachycardia
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54. none
• Rate?
• Regularity? irregularly irreg.
none
wide, if recognizable
• P waves?
• PR interval? none
• QRS duration?
Interpretation? Ventricular Fibrillation
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55. 1ST DEGREE AV BLOCK
• PR Interval- > 0.20 s (five small squares)
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56. 60 bpm
• Rate?
• Regularity? regular
normal
0.08 s
• P waves?
• PR interval? 0.36 s
• QRS duration?
Interpretation? 1st Degree AV Block
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57. 2ND DEGREE AV BLOCK, TYPE I
PR interval progressively lengthens, then the impulse is completely blocked
(P wave not followed by QRS).
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58. 50 bpm
• Rate?
• Regularity? regularly irregular
normal, but 4th no QRS
0.08 s
• P waves?
• PR interval? lengthens
• QRS duration?
Interpretation? 2nd Degree AV Block, Type I
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59. 2ND DEGREE AV BLOCK
• Occasional P waves are completely blocked (P wave not followed by QRS).
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60. 40 bpm
• Rate?
• Regularity? regular
2 of 3 no QRS
0.08 s
• P waves?
• PR interval? 0.14 s
• QRS duration?
Interpretation? 2nd Degree AV Block , Type II
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61. 3RD DEGREE AV BLOCK
P waves are completely blocked in the AV junction; QRS complexes originate
independently from below the junction.
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62. 40 bpm
• Rate?
• Regularity? regular
no relation to QRS
wide (> 0.12 s)
• P waves?
• PR interval? none
• QRS duration?
Interpretation? 3rd Degree AV Block
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63. ASYSTOLE
• No electrical activity is seen
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64. AARATI PAHARI

65. MONITOR READINGS
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66. Atrial fibrillation
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67. Ventricular fibrillation
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68. Ventricular tachycardia
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69. NURSES RESPONSIBILITIES
AND COMMON ARTIFACTS
ENCOUNTERED
PRESENTED BY : AARATI PAHARI
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70. NURSES RESPONSIBILITIES
• Gain consent
• Explain the procedure
• Expose their chest as well as limbs .
• Proper positioning
• Skin Preparation
• Swab the electrode placement
• Maintain privacy
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71. ARTIFACTS
• ECG abnormalities which are a measurement of cardiac potential on the body
surface and are not related to electrical activity of the heart.
• As a result of artifacts, normal components of the ECG can be distorted.
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72. LOOSE LEAD ARTIFACT
• Diaphoretic patient :electrodes simply does not stick to the patient’s body.
• Placement of the electrode over hair.
• To troubleshoot this problem make sure you prep the skin carefully!
• In this example loose lead artifact can be seen in leads I and II.
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73. WANDERING BASELINE ARTIFACT
Wandering baseline artifact presents as a slow, undulating baseline on the
electrocardiogram. It can be caused by patient movement, including breathing
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74. MUSCLE TREMOR ARTIFACT
• It is a type of motion artifact. Usually it’s occurs because when patient is cold and
shivering. It can also occur when patients prop themselves up by their arms.
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75. ELECTROMAGNETIC INTERFERENCE
It usually results from electrical power lines, electrical equipment, and mobile
telephones.
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76. REDUCING ARTIFACTS
• Perform good skin preparation
• Check the electrodes
• Make sure the patient is warm, relaxed and does not move or speak
• Proper placement of electrodes
• Check the Patient cable connection to the ECG device
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77. DISCUSSION
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78. CASE SCENARIO 1
A 58-year-old male presents to the ED after experiencing intermittent chest pain for
2 days. He describes substernal chest pressure radiating to his jaw. He is short of
breath and diaphoretic. His temperature is 100.0, blood pressure is 140/90 mm Hg,
respirations are 22 per minute, heart rate is 70 beats per minute and oxygen is 92%
on room air. His ECG is below
What are the main findings according to the ECG tracing?
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79. AARATI PAHARI

80. FINDINGS
• Rate
• Regularity
• P wave
• PR interval
• QRS duration
• ST segment
• 100 bpm
• Regular
• Normal
• Normal
• Normal
• Elevation
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81. CASE SCENARIO 2
A patients presents at emergency department with sudden onset of weakness and
pre-syncope. He is experiencing shortness of breath, diaphoresis and feels
significant palpitations. He is afebrile with a blood pressure of 80/40 mm Hg, heart
rate of 240 beats per minute, respirations 26 beats per minute and oxygen 88% on
room air. His ECG is below
What are the main findings according to the ECG tracing?
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82. AARATI PAHARI

83. FINDINGS
• Rate
• Regularity
• P wave
• PR interval
• QRS duration
• 160 bpm
• Regular
• None
• None
• Wide
Ventricular Tachycardia
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84. CASE SCENARIO 3
A 55-year-old male with a history of hypertension and diabetes presents to the
emergency department with substernal chest pain radiating to his left arm. He has
diaphoresis and shortness of breath. He has vomited twice and now is intermittently
feeling lightheaded. His temperature is 37.4°C, heart rate is 70 bpm, blood pressure
is 110/70 mm Hg and respiratory rate is 24 breaths per minute. His ECG is below.
What are the main findings according to the ECG tracing?
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85. AARATI PAHARI

86. FINDINGS
• Rate
• Regularity
• P wave
• PR interval
• QRS duration
• ST segment
• 60 bpm
• Irregular
• Normal
• Prolonged
• Normal
• Elevation , depression
2nd degree type I AV block
ST elevation (leads II, III, and aVF)
ST depression (leads I and aVL)
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87. ANY QUERIES ????
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88. Thank You !!
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