1. ECG
M.Bayat
Ph.D

2. Galvanometer
Willem Einthoven (1860–1927), known as the creator of the electrocardiograph, won a Nobel Prize in 1924 for his contributions to the field of electrocardiography.

5. string galvanometer
Willem Einthoven (1860–1927), known as the creator of the electrocardiograph, won a Nobel Prize in 1924 for his contributions to the field of electrocardiography.

6. The location of 10 electrodes

7. aVR, aVL, aVF (augmented limb leads)
Summary of Leads
Limb Leads
Precordial Leads
Bipolar
I, II, III
(standard limb leads) -
Unipolar
aVR, aVL, aVF (augmented limb leads)
V1-V6

8. The 12-Lead view
Leads are electrodes which measure the difference in electrical potential between either
Each limb lead I, II, III, AVR, AVL, AVF records from a different angle
All six limb leads intersect and visualize a frontal plane
The six chest leads (precordial) V1, V2, V3, V4, V5, V6 view the body in the horizontal plane to the AV node
The 12 lead ECG forms a camera view from 12 angles

9. Electrical potential differences are measured between the poles
Limb leads I, II, III are bipolar and have a negative and positive pole
Electrical potential differences are measured between the poles
Right II
III I + + +

10. Augmented voltage + + +

11. Voltage wilson=Vw

15. Views from Augmented and Limb Leads- Frontal

17. Precordial Leads

18. Right ventricle
Left ventricle
septal

19. Precordial lead snapshots
Think of each precordial lead as a horizontal view of the heart at the AV node
With the limb leads and the precordial leads you have a snapshot of heart portions

21. II, III and AVF
I and AVL
V3 & v4
V5 & v6
V1 & v2
Where the positive electrode is positioned, determines what part of the heart is seen!

22. V5,V6

24. Inferior MI
II, III, AVF

25. Lateral MI
I, AVL, V5, V6

26. Septal wall MI
V2,v3

27. Posterior MI
V1, V2

28. Anterior MI
V3,V4

29. Anatomic Groups (Summary)
Right ventricle
Apex

30. The ECG Tracing: Waves P- wave QRS- Complex T- wave
Marks the beginning of the cardiac cycle and measures the electrical impulse that causes atrial depolarization and mechanical contraction
QRS- Complex
Measures the impulse that causes ventricular depolarization
Q-wave- the first downward deflection following the P-wave
R-wave- first upward deflection following P wave
S-wave- the first downward deflection following the R-wave
T- wave
Marks ventricular repolarization that ends the cardiac cycle

33. BASIC TERMINOLOGY Arrhythmia: Abnormal rhythm
Baseline: Flat, straight, isoelectric line
Waveform: Movement away from the baseline, up or down
Segment: A line between waveforms
Interval: A waveform plus a segment
Complex: Combination of several waveforms

34. V3
aVR
aVL
V1,V2 I - +
Why do Recorded waves by various types of leads have different shape ?

35. II

36. Depolarization and repolarization in ventricles- 1 2 + 5 3 4 - +

37. Views from Augmented and Limb Leads- Frontal
III I II
III
III

38. R R r s Q S

39. V5,V6

40. I+III=II

41. R R r s Q S

42. R R R R r r s s s S S S

43. Do you know determining the Heart Rate by ECG recording?

44. Determining the Heart Rate
Rule of 300
10 Second Rule
60/RR interval sec
Lead V1,I,II are the best lead for evaluation of P wave and heart rate
300
1500
Large square in RR
Small square in RR

45. What is the heart rate? (300 / 6) = 50 bpm
(300 / 6) = 50 bpm
If paper speed is 25 mm/s each small square is 0.04 s

46. What is the heart rate?
(300 / ~ 4) = ~ 75 bpm

47. What is the heart rate?
(300 / 1.5) = 200 bpm

50. The Rule of 300 It may be easiest to memorize the following table:
# of big boxes
Rate 1
300 2
150 3
100 4 75 5 60 6 50

51. 10 Second Rule
As most EKGs record 10 seconds of rhythm per page, one can simply count the number of beats present on the EKG and multiply by 6 to get the number of beats per 60 seconds. This method works well for irregular rhythms.

52. The QRS Axis
Do you know determining the QRS axis by ECG recording?

54. The QRS Axis
the normal QRS axis is defined as ranging from +20° to +100°.
+20° to -90° is referred to as a left axis deviation (LAD)
+100° to +180° is referred to as a right axis deviation (RAD)
LAD
+20
+100

55. The Quadrant Approach
1. Examine the QRS complex in leads I and aVF to determine if they are predominantly positive or predominantly negative. The combination should place the axis into one of the 4 quadrants below. In the event that LAD is present, examine lead II to determine if this deviation is pathologic. If the QRS in II is predominantly positive, the LAD is non-pathologic (in other words, the axis is normal). If it is predominantly negative, it is pathologic.

56. Quadrant Approach: Example 1
The Alan E. Lindsay ECG Learning Center
Negative in I, positive in aVF  RAD

57. Quadrant Approach: Example 2
The Alan E. Lindsay ECG Learning Center
Positive in I, negative in aVF  Predominantly positive in II 
Normal Axis (non-pathologic LAD)

58. The Equiphasic Approach
1. Determine which lead contains the most equiphasic QRS complex. The fact that the QRS complex in this lead is equally positive and negative indicates that the net electrical vector (i.e. overall QRS axis) is perpendicular to the axis of this particular lead. 2. Examine the QRS complex in whichever lead lies 90° away from the lead identified in step 1. If the QRS complex in this second lead is predominantly positive, than the axis of this lead is approximately the same as the net QRS axis. If the QRS complex is predominantly negative, than the net QRS axis lies 180° from the axis of this lead.

59. Determining the Axis Predominantly Positive Predominantly Negative
Equiphasic

60. Equiphasic Approach: Example 1
The Alan E. Lindsay ECG Learning Center ;
Equiphasic in aVF  Predominantly positive in I  QRS axis ≈ 0°

61. Equiphasic Approach: Example 2
Equiphasic in II  Predominantly negative in aVL  QRS axis ≈ +150°

62. Equiphasic Approach: Example 2
aVL
150
III
II 60

63. Please calculate Net potential
aVR
aVF

64. Left ventricular hypertrophy
LAD