1. Advanced ECG’s for MLA’s
Cathie Cousins, RN, BScN, CCN(C)

2. Cathie Cousins,RN BScN CCN(C)
Objectives
1. To review Basic Concepts for the 12-Lead ECG
To discuss the following on the 12-Lead ECG
2. Bradycardia
3. Tachycardia
4. Ventricular Ectopy
5. ST and T wave changes
6. Pacemakers
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

3. Cathie Cousins,RN BScN CCN(C)
1. Basic Concepts
The heart is a pump with an electrical conduction system
2 basic types of cardiac cells in the heart
Myocardial cells or “muscle” cells
Specialized cells of the conduction system or “pacemaker” cells
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

4. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

5. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

6. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

7. Electrical Axes and Vectors
Each of the 12 leads on the ECG has a different pattern because each lead views the hearts electrical axis from a different position
Atrial and ventricular depolarization and repolarization generate an electric current known as an electrical axis or vector (different from the axis of a lead)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

8. Cathie Cousins,RN BScN CCN(C)
Average of all the ventricular vectors points to the left and downward
Knowing the electrical axis of the heart enables us to determine the normal pattern of each lead and the cause for altered patterns in each lead
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

9. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

10. Cathie Cousins,RN BScN CCN(C)
Rate
Both the atrial and ventricular rates should be measured
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

11. The Grid Method for Rate
Uses the distance between 2 sequential complexes on the ECG
Each small square represents 0.04 seconds
small squares in 1 minute
large squares in 1 minute
Count the large squares between P waves for atrial rate and R waves for ventricular rate
300 ÷ number of large squares = number of beats/min
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

12. Cathie Cousins,RN BScN CCN(C)
Quick Tips
300 ÷ 5 large squares = 60 bpm
5 or > large squares per minute = Bradycardia
300 ÷ 3 large squares = 100 bpm
3 or > large squares per minute = Tachycardia ÷
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

13. Cathie Cousins,RN BScN CCN(C)
2. Bradycardia
Bradycardia is a heart rate < 60/min
Bradycardia can be due a slow sinus rate, the origin of the rhythm or an AV block:
- Sinus Bradycardia
- Junctional Rhythm
- Idioventricular Rhythm
- 2° AV Block Type I
- 2° AV Block Type II
- 3° AV Block
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

14. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

15. Cathie Cousins,RN BScN CCN(C)
Sinus Bradycardia
Sinus node is pacing at a rate < 60/min
P wave, QRS normal
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

16. Cathie Cousins,RN BScN CCN(C)
Junctional Rhythm
Sinus node and atria fail to pace the heart.
AV junction paces at → 40-60/min
No P wave or PR interval < 0.12, QRS normal
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

17. Idioventricular Rhythm
Sinus node, atria, and AV junction fail to pace. Ectopic pacemaker in the ventricles paces at → 20-40/min
No P wave, QRS wide, ST & T waves often abnormal
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

18. Cathie Cousins,RN BScN CCN(C)
AV Blocks
2° Type I and 2°Type II AV Blocks, sinus node paces the heart
Not ever P wave results in QRS,
QRS normal or wide
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

19. Cathie Cousins,RN BScN CCN(C)
3° AV Block, sinus node paces the heart
P waves do not result in QRS
AV junction paces, QRS normal
Ventricles pace, QRS wide
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

20. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

21. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

22. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

23. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

24. Cathie Cousins,RN BScN CCN(C)
3. Tachycardia
Tachycardia is a heart rate > 100/min
Tachycardia can be due to:
- Sinus Tachycardia
- Supraventricular Tachycardia
- Ventricular Tachycardia
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

25. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

26. Cathie Cousins,RN BScN CCN(C)
Sinus Tachycardia
Sinus node is pacing at a rate > 100/min
P wave, QRS normal
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

27. Superventricular Tachycardia
Ectopic focus in atria or AV junction paces the heart
or Abnormal conduction thru AV node
or Accessory pathway
P wave or no P wave, QRS narrow or wide,
rate > 150/min
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

28. Ventricular Tachycardia
Ectopic pacemaker in ventricles paces the heart
No P wave, QRS wide and bizarre
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

29. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

30. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

31. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

32. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

33. 4. Premature Ventricular Contractions
QRS Duration
QRS duration - depolarization of right and left ventricles, from the endocardium to epicardium
Normal QRS duration sec
QRS duration > sec, a conduction delay exists in the bundle branches, Purkinjie network or ventricular myocardium, or ventricular ectopic conduction exists
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

34. Cathie Cousins,RN BScN CCN(C)
PVC’s, premature ventricular complexes:
the premature beat originates in an ectopic
focus in one ventricle, it depolarizes that
ventricle, then the other
No P wave, QRS wide & bizarre, ST often abnormal, T wave often opposite the rhythm
Multifocal PVC’s come from more than one ectopic focus, each foci has a different shape
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

35. Cathie Cousins,RN BScN CCN(C)
1 PVC = a PVC
2 PVC’s = couplet
3 PVC’s = triplet
4 PVC’s = ventricular tachycardia
Every 2nd PVC = bigeminy
Every 3rd PVC = trigeminy
Bigeminy or trigeminy can refer to any ectopic beat so clarify -
eg. bigeminal PVC’s or bigeminal PAC’s, etc.
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

36. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

37. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

38. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

39. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

40. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

41. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

42. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

43. Cathie Cousins,RN BScN CCN(C)
5a. ST Segments
ST segment = end of ventricular repolarization + early part of ventricular repolarization
ST segment normally isoelectric
Ischemic + injured myocardial cells altered membrane potentials, this allows a current to flow as seen in ST elevation + depression
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

44. Cathie Cousins,RN BScN CCN(C)
Measuring ST Segments
ST measurement = vertical difference between the isoelectric line + end of QRS complex, the “J” point”
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

45. Cathie Cousins,RN BScN CCN(C)
ST Segment Elevation
ST segment elevation = >1 mm (>0.1 mV) above baseline after the J point
ST segment elevation due to severe injury temporary until ischemia resolved or injured heart tissue heals or dies
ST segments elevate in leads facing the injury
ST segments depress in leads opposite (reciprocal ) leads
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

46. Types of ST Elevation in AMI
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

47. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

48. Other Common Causes of ST Segment Elevation
Coronary artery vasospasm
Acute pericarditis
Ventricular aneursym
Hyperkalemia
Non-specific ST-T wave changes
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

49. Cathie Cousins,RN BScN CCN(C)
ST Segment Depression
ST segment depression = > 1 mm below baseline after the J point
ST segment depression due to severe ischemia temporary until ischemia resolved or heart tissue heals
ST segments depress in leads facing the ischemia
ST segments elevate in opposite (reciprocal) leads
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

50. Types of ST Depression in AMI
Different types of
ST depression in AMI:
- downsloping
- horizontal
- upsloping
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

51. Other Common Causes of ST Segment Depression
Left and right ventricular hypertrophy
Left and right bundle branch block
Digitalis in therapeutic and toxic doses
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

52. Acute MI Facing Leads Opposite Leads
Anterior
Septal V1-V None
Anterior V3-V None
Lateral I, aVL, & V5 or V II, III, & aVF
Inferior II, III, & aVF I & aVL
Posterior V7,V8, V9 on 18 lead V1-V4
Right Ventricle V4R, V5R, V6R on 18 lead None
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

53. Cathie Cousins,RN BScN CCN(C)
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Cathie Cousins,RN BScN CCN(C)

54. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

55. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

56. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

57. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

58. Cathie Cousins,RN BScN CCN(C)
5b. T waves
A T wave represents ventricular depolarization
T waves normally upright, rounded, and slightly asymmetrical. Normally negative in aVR.
Normally 1/8 to 2/3 the height of the QRS complex
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

59. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

60. Cathie Cousins,RN BScN CCN(C)
Abnormal T Waves in AMI
Normal Heart -
positive T wave
Subendocardial
Ischemia -
symmetrically
positive tall,
peaked T wave
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

61. Cathie Cousins,RN BScN CCN(C)
Subepicardial
Ischemia -
symmetrically
negative deep T wave
Late phases in AMI -
deeply inverted
T waves with
abnormal Q waves
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

62. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

63. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

64. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

65. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

66. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

67. Cathie Cousins,RN BScN CCN(C)
6. Pacemakers
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

68. The 3 Functions of Pacing
1. Sensing – the ability of the pacemaker to recognize the patient’s intrinsic heartbeat
2. Pacing – the pacemaker produces a stimulus either when the sensing circuit does not detect an intrinsic heartbeat or at a predetermined time interval
3. Capturing – the depolarization of the myocardium in response to pacing
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

69. Cathie Cousins,RN BScN CCN(C)
Pacemaker Codes
I Chamber(s) paced
II Chamber(s) sensed
III Response to sensing
IV Programmable function(s)
V Antitachyarrhythmia function(s)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

70. Pacing Leads Sites - Permanent
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

71. Pacing Leads Sites - Temporary
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

72. Pacemaker Sites - Temporary
Transcutaneous
– External Pacing
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

73. Cathie Cousins,RN BScN CCN(C)
Pacemaker Strip 1
1. Sensing
2. Pacing
3. Capturing
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

74. Cathie Cousins,RN BScN CCN(C)
Pacemaker Strip 2
1. Sensing
2. Pacing
3. Capturing
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

75. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

76. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

77. Cathie Cousins,RN BScN CCN(C)
May 13, 2006
Cathie Cousins,RN BScN CCN(C)

78. Cathie Cousins,RN BScN CCN(C)
Thank You
Remember: It is the team that assists the patient in achieving wellness.
Thank you and enjoy the exciting world of 12 Lead ECG’s.
May 13, 2006
Cathie Cousins,RN BScN CCN(C)