1. Normal ECG: Rate and Rhythm
Read chapters 4 and 22

2. ECG Interpretation* *See Chapter 22 Standardization Rate RR interval
Heart rate
Rhythm
PP interval
P wave
width, height, shape, etc.
PR interval
QRS
width (and height)
axis
R wave progression
abnormal Q waves
ST segment
T waves
QT interval
U waves
*See Chapter 22

4. ECG Interpretation Univ. of Wisconsin Medical School

5. The Normal ECG
Normal = normal sinus rhythm

6. Rate R-R interval Is it regular? What is the heart rate?
300, 150, 100, 75, 60, 50
300 / (# of large boxes)
1500 / (# of small boxes)
Count the number of cardiac cycles in 10 seconds and multiple by 6.

8. Rate
Bradycardia
less than 60 bpm
Tachycardia
greater than 100 bpm

9. Rate
P-P interval

10. Rhythm
P wave
PR interval
QRS

11. 4. P Wave Lead II and aVR Positive in II Negative in aVR
< 2.5 mm in amplitude
< 0.12 sec. in width

12. Normal P Wave aVR? II? Figures 4-2 and 4-3
Normal direction of atrial depolarization
aVR?
II?
Figures 4-2 and 4-3

13. Abnormal P Wave
Direction of atrial depolarization with junction rhythm
aVR?
II?
This is an example of a retrograde conduction

15. P wave The same direction as QRS Only one P wave in front of QRS
Do all the P waves look alike?

16. 5. PR interval
seconds

17. 6. QRS Complex What is the width? (less than 0.10 seconds)
Do all the QRS waves in the same lead look alike?
R wave progression
Axis
Abnormal Q waves (infarction)

20. QRS Complex
Q waves

21. Normal QRS
Two phases
brief phase; depolarization of ventricular septum
longer phase; depolarization of both ventricles but the left is larger

22. First Phase
Depolarization of ventricular septum

23. Second Phase
Depolarization of both ventricles but the left is larger

24. Precordial Leads V6 V1

25. Normal QRS
V6?
V6?
V1?
V1?
Fig. 4-6

26. Normal QRS V1 V6

27. Normal QRS
Septal r wave
Septal q wave

28. 6. QRS Complex
R wave progression

29. Normal R Wave Progression
Transition Zone?

30. R Wave Progression
Transition Zone?

31. Transition Zone
Figure 4-7

32. Early & Delayed Transition
V V V V V V6
Figure 4-7

33. 6. QRS Complex What is the electrical axis? normal left axis deviation
right axis deviation
extreme axis deviation

34. 7. St Segment
ST segment elevation or depression
(see chapters 8 & 9)

35. 8. T Wave Normally positive where QRS wave is positive
V3- V6 and II, but negative in aVR
Abnormally tall T waves

36. Practice ECG Library http://www.ecglibrary.com/ecghome.html
ECG: The Art of Interpretation

37. Normal

38. Not normal PR interval -
Mobitz Type II block

39. Not normal
LAD, R wave progression
RBB w/inferior MI

40. Not normal -
First degree block, left atrial enlargement, left bundle branch block, & inferior MI

41. Not normal
Atrial fibrillation

42. Normal

43. Not normal
Junctional rhythm

44. LAD, late R wave progression
Not normal
LAD, late R wave progression
Acute MI

45. Premature ventricular contractions
Not normal
Premature ventricular contractions

46. Ventricular tachycardia: note fast rate and wide bizarre QRS.
Not normal
Ventricular tachycardia: note fast rate and wide bizarre QRS.

47. Normal

48. Second degree AV block - type II
Not normal
Second degree AV block - type II

49. Not normal
RAD, R wave progression

50. Not normal
Third degree AV block

51. Right bundle branch block. Note the wide QRS waves
Not normal
Right bundle branch block. Note the wide QRS waves

52. Normal

53. Left bundle branch block. Note the wide QRS waves
Not normal
Left bundle branch block. Note the wide QRS waves

54. a. yes
b. vertical
c. V3
d. yes
e. yes
f. yes

55. 2. No. Although there are P waves, they are negative
2. No. Although there are P waves, they are negative. negative P waves indicate a retrograde conduction likely coming from the AV junction.