Normal ECG: Rate and Rhythm

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

2. ECG Interpretation* • 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 • http://www.fammed.wisc.edu/pcc/ecg/

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 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 • 0.12 - 0.20 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 V1 V2 V3 V4 V5 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 • http://www.12leadecg.com/full/

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. Not normal LAD, late R wave progression Acute MI

45. Not normal Premature ventricular contractions

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

47. Normal

48. Not normal Second degree AV block - type II

49. Not normal RAD, R wave progression

50. Not normal Third degree AV block