This document provides an overview of electrocardiography (ECG), including the conduction system of the heart, types of ECG monitoring, basics of ECG interpretation including key waves and intervals, methods for determining heart rate, cardiac rhythm determination, normal ECG patterns, common arrhythmias, and electrode placement for 12-lead ECGs. The objectives are to review heart electrical conduction, describe ECG monitoring and interpretation, identify normal and abnormal ECG patterns, and understand factors such as rate, rhythm, P waves, and intervals that are used to interpret ECGs.

1. ELECTROCARDIOGRAPHY

2. OBJECTIVES
• Review the anatomy and physiology of
the electrical conduction of the heart
• Interpret the term elecrocardiography
• Describe the types of ecg monitoring
• Interprets the basics of ecg
• Determine the heart rate from ecg
• Explain the cardiac rhythm determinatation
• Understand the 12 lead ecg
• Differentiate the electrode placement
• Distinguish abnormal ecg from normal ecg

3. CONDUCTING SYSTEM OF HEART

4. ELECTROCARDIOGRAM
ECG is a graphic representation of the
electrical currents of the heart

5. TYPES OF ECG MONITORING
• Continuous electrocardiographic monitoring
• Hardwire cardiac monitoring
• Telemetry
• Ambulatory elecrocardiography
• Transtelephonic monitoring
• Wireless mobile cardiac monitoring systems

6. BASIC ELECTROCARDIOGRAPHY

7. P WAVE
• First wave seen
• Small rounded,
upright
(positive) wave
indicating atrial
depolarization
(and
contraction)
• < 0.12 sec

8. QRS COMPLEX
• Three deflections following P wave
• Indicates ventricular depolarization
(andcontraction)
• Q Wave: First negative deflection
• R Wave: First positive deflection
• S Wave: First negative deflection after R wave
• < 0.10 sec

10. PR INTERVAL
• Distance between beginning of P wave and
beginning of QRS complex
• Measures time during which a depolarization
wave travels from the atria to the ventricles
• 0.12 – 0.20 sec

12. ST SEGMENT
• Distance between S wave and beginning of
T wave
• Measures time between ventricular
depolarization and beginning of repolarization

14. T WAVE
• Rounded upright (positive) wave following
QRS
• Represents ventricular repolarization

16. U WAVE
• Small rounded, upright wave following
T wave
• Most easily seen with a slow HR.
• Represents repolarization of Purkinje fibers

18. QT INTERVAL
• Measured from beginning of QRS to end of
T wave.
• Represents total ventricular activity

20. RATE DETERMINATION
LARGE BOX METHOD
• Regular rhythms can be quickly determined by
counting the number of large graph boxes
between two R waves. That number is divided
INTO 300 to calculate bpm..

21. SMALL BOX METHOD
• Sometimes it is necessary to count the
number of small boxes between two R waves
for fast heart rates. That number isdivided into
1500 to calculate bpm.

22. 6 SEC STRIP
• The best method for measuring irregular rates
with varying R-R intervals is to count the
number of R waves in a 6-sec strip and
multiply by 10.This gives the average number
of bpm.

23. CARDIAC RHYTHM DETERMINATION
• REGULARITY
Measure R-R intervals and P-P intervals.
Regular: Intervals consistent
Regularly irregular: Repeating pattern
Irregular: No pattern

24. • RATE
The bpm is commonly the ventricular rate.
If atrial and ventricular rates differ, as in a 3rd
degree block, measure both rates.
Normal: 60–100 bpm
Slow (bradycardia): 60 bpm
Fast (tachycardia): 100 bpm

25. P WAVES
• If present: Same in size, shape, position?
• Does each QRS have a P wave?
• Normal: Upright (positive) and uniform
• Inverted: Negative
• Notched: P'
• None: Rhythm is junctional or ventricular

26. • P R INTERVAL
• Constant: Intervals are the same.
• Variable: Intervals differ.
• Normal: 0.12–0.20 sec and constant

27. • QRS COMPLEX
• Normal: 0.06–0.10 sec
• Wide: 0.10 sec
• None: Absent

28. LEADS OF ECG

31. LEAD PLACEMENT

35. NORMAL SINUS RHYTHM

36. SINUS BRADYCARDIA

37. SINUS TACHYCARDIA

38. PREMATURE ATRIAL COMPLEX

39. ATRIAL FLUTTER

40. ATRIAL FIBRILLATION

41. PREMATURE VENTRICULAR COMPLEX

42. VENTRICULAR TACHYCARDIA
• MONOMORHIC

43. • POLYMORHIC

44. VENTRICULAR FIBRILLATION

45. VENTRICULAR ASYSTOLE

46. FIRST DEGREE AV BLOCK

47. SECOND DEGREE A.V BLOCK
• TYPE 1

48. • TYPE 2

49. THIRD DEGREE A.V BLOCK

50. BUNDLE BRANCH BLOCK

51. ISCHEMIA ,INJURY,INFARCTION

54. ENLARGEMENTS
• LEFT ATRIAL

55. LEFT VENTRICULAR

56. RIGHT VENTRICULAR

57. ELECTROLYTE IMBALANCES

58. JOURNAL
TIME

60. ANSWERS

61. • RATE:214 bpm
• RHYTHM: regular
• P WAVE: none
• PR INTERVAL: none
• QRS COMPLEX: >0.12 bizarre
• INTERPRETATION: VT- MONOMORHIC

62. • RATE: 75 bpm
• RHYTHM: regular
• P WAVE: normal
• PR INTERVAL:0.16
• QRS COMPLEX:0.08
• INTERPRETATION: NORMAL SINUS RHYTHM

63. • RATE:50 -75 bpm
• RHYTHM: irregular
• P WAVE: normal
• PR INTERVAL:0.12- 0.28
• QRS COMPLEX:0.08
• INTERPRETATION:2nd DEGREE A.V BLOCK
TYPE 1

64. • RATE: 35 BPM
• RHYTHM: regular
• P WAVE: normal
• PR INTERVAL: 0.16
• QRS COMPLEX:0.10
• INTERPRETATION: SINUS BRADYCARDIA

65. REFERENCES
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Cardiology.3rd ed.Philadelphia:Elsevier
publication;2010.
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Internal Medicine.17th ed (vol I).USA:McGraw
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Nursing.7th edn.Missouri:Saunders;2005
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