This document provides an overview of electrocardiography (ECG), including how an ECG works, the basics of recording an ECG, ECG leads, normal ECG waveforms and intervals, interpreting an ECG, common abnormalities, and how to report an ECG. It discusses topics such as the cardiac conduction system, Einthoven's triangle, the 12-lead ECG, determining heart rate and axis, normal sinus rhythm, P waves, QRS complex, ST segment, T waves, and the QT interval.

1. Basics of Electrocardiography Dr.K.Subramanyam 23-3-2009

5. Recording ECG William Einthoven

7. Recording an ECG

9. ECG Paper: Dimensions 5 mm 1 mm 0.1 mV 0.04 sec 0.2 sec Speed = rate Voltage ~Mass

14. Standard Limb Leads

15. Precordial Leads

16. Precordial Leads

17. Summary of Leads V 1 -V 6 aVR, aVL, aVF (augmented limb leads) Unipolar - I, II, III (standard limb leads) Bipolar Precordial Leads Limb Leads

18. Limb Leads (Einthoven leads) Einthoven triangle Einthoven Rule I+II+III==0 I+(-II)+III=0 I+III=II

20. Arrangement of Leads on the EKG

21. Anatomic Groups (Septum)

22. Anatomic Groups (Anterior Wall)

23. Anatomic Groups (Lateral Wall)

24. Anatomic Groups (Inferior Wall)

25. Anatomic Groups (Summary)

26. Localising the arterial territory Inferior II, III, aVF Lateral I, AVL, V5-V6 Anterior / Septal V1-V4

32. Interpretation of an ECG

34. Wave forms

40. QRS axis Dr.K.Subramanyam 9-4-2009

59. The QRS Axis By near-consensus, the normal QRS axis is defined as ranging from -30 ° to +90 ° . -30 ° to -90 ° is referred to as a left axis deviation (LAD) +90 ° to +180 ° is referred to as a right axis deviation (RAD)

62. Determining the Axis Predominantly Positive Predominantly Negative Equiphasic

65. Example 1 Negative in I, positive in aVF  RAD

66. Example 2 Positive in I, negative in aVF  Predominantly positive in II  Normal Axis (non-pathologic LAD)

68. Example 1 Equiphasic in aVF  Predominantly positive in I  QRS axis ≈ 0°

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

70. Using leads I, II, III NEGATIVE NEGATIVE UPRIGHT Pathological Left Axis UPRIGHT UPRIGHT BIPHASIC NEGATIVE NEGATIVE Right Axis NEGATIVE NEGATIVE NEGATIVE Extreme Right Axis NEGATIVE UPRIGHT / BIPHASIC UPRIGHT Physiological Left Axis UPRIGHT UPRIGHT UPRIGHT Normal LEAD 3 LEAD 2 LEAD 1

73. The Normal ECG Dr.K.Subramanyam 30-3-2009

76. Sinus Arrhythmia ECG Characteristics: Presence of sinus P waves Variation of the PP interval which cannot be attributed to either SA nodal block or PACs When the variations in PP interval occur in phase with respiration, this is considered to be a normal variant. When they are unrelated to respiration, they may be caused by the same etiologies leading to sinus bradycardia.

78. Normal P wave

103. Normal Variants in the ECG

105. Persistent juvenile pattern

108. Reporting an ECG

109. 1. Patient Details “ Whose ECG is it ?!”

110. 2. Standardisation and lead placement “Is it properly taken ?”

115. 3. Analysis of Rate, Rhythm and Axis

118. 4. Segment and wave form analysis

121. 5. Chamber enlargements

122. Final Impression “ Does the ECG correlate with the clinical scenario ?”

123. Thank you !