How to read ECG systematically with practice strips

This lecture simplifies the steps of reading ECG systematically. It starts with a simple heart anatomy and the logical steps that should be followed to perfect ECG reading without missing any abnormality. Finally, there are some practice ECG strips that include but not only MI, STEMI, Wellens syndrome, Pulmonary embolism, LVH, arrhythmias... and others

1. Dr. Khaled H Alkhodari Clinical Teaching Assistant at IUG 2020-2021 ECG revision & Practice

2. https://litfl.com/ecg-library/

3. All Limb Leads

4. Precordial Leads

5. Anatomic Groups (Septum)

6. Anatomic Groups (Anterior Wall)

7. Anatomic Groups (Lateral Wall)

8. Anatomic Groups (Inferior Wall)

9. Anatomic Groups (Summary)

10. https://ecgwaves.com/topic/localization-localize-myocardial-infarction-ischemia-coronary-artery-occlusion-culprit-stemi/

11. Interpretation Steps Hx and Examination Name and Date Calibration Detect errors Cardiac Axis Rhythm Rate P wave PR interval QRS complex T wave ST segment QT interval

12. speed of 25mm /sec Small square = 1 mm = 0.04 s = 40 ms Large square = 5 mm = 0.2 s = 200 ms

13. Determining the Axis The Quadrant Approach The Equiphasic Approach

14. 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)

15. Determining the Axis Predominantly Positive Predominantly Negative Equiphasic

16. The Quadrant Approach 1. Examine the QRS complex in leads I and aVF to determine if they are predominantly positive or predominantly negative. The combination should place the axis into one of the 4 quadrants below. Or normal

17. The Quadrant Approach 2. In the event that LAD is present, examine lead II to determine if this deviation is pathologic. If the QRS in II is predominantly positive, the LAD is non-pathologic (in other words, the axis is normal). If it is predominantly negative, it is pathologic.

18. Quadrant Approach: Example 1 Negative in I, positive in aVF  RAD The Alan E. Lindsay ECG Learning Center http://medstat.med.utah.edu/kw/ecg/

19. Quadrant Approach: Example 2 Positive in I, negative in aVF  Predominantly positive in II  Normal Axis The Alan E. Lindsay ECG Learning Center http://medstat.med.utah.edu/kw/ecg/

20. Left axis deviation

21. Right Axis Deviation

22. Normal Axis: (-30 – 90) degree Left Axis deviation (LAD): < - 30 degree Normal variant / mechanical shift (high diaphragm) Left anterior hemiblock / LBBB / WPW / Inferior MI LVH / Ostium primum ASD Right Axis Deviation (RAD): > 90 degree Normal variant (tall & thin persons) / Chronic Lung Disease Left posterior hemiblock / RVH / PHTN (PE) Ostium secondum ASD / VSD / Anterolateral MI / WPW

23. Interpretation Steps Hx and Examination Name and Date Calibration Detect errors Cardiac Axis Rhythm Rate P wave PR interval QRS complex T wave ST segment QT interval

24. Rhythm

25. Rate

26. Rate Regular 300/no of large squares 300/4.5 = 67b/m

27. Irregular

28. Short P-R WPW Long P-R 1 st degree HB

29. Normal QRS 110 ms <3 small sq

30. Normal QRS

31. Sinus rhythm + LBBB

32. Sinus rhythm + RBBB

33. ST Depression

34. Benign with tachycardia Ischemic in 99% Ischemic in 50%

35. Peaked T wave

36. T inversion T inversion : normal variant in black patents, hypertrophy (HOCM) ischemia, digoxin

37. (CULPRIT LESION): LM: Widespread horizontal ST depression, most prominent in leads I, II and V4-6 or ≥ 8 LEADS ST elevation in aVR ≥ 1mm ST elevation in aVR ≥ V1 Except Tachycardia-Related ST Depression Widespread ST depression (with reciprocal STE in aVR ) is a common finding in patients with supraventricular tachycardias such as AVNRT or atrial flutter .  and may be due to: Rate-related ischaemia (O2 demand > supply) Unmasking of underlying coronary artery disease (i.e. tachycardia as a “stress test”) A pure electrical phenomenon (e.g. the young patient with SVT who is relatively asymptomatic and has normal coronary arteries)

38. However, ST elevation in aVR is not entirely specific to LMCA occlusion. It may also be seen with: Proximal left anterior descending artery (LAD) occlusion Severe triple-vessel disease (3VD) Diffuse subendocardial ischaemia – e.g. due to O2 supply/demand mismatch

39. Anterior MI ST elevation v1-4 Several ECG criteria have been reported to indicate a LAD artery occlusion proximal to the first septal perforator branch : (1) ST elevation in lead aVR (2) right bundle branch block (3) ST depression in lead V5 or Q wave in aVL (4) ST elevation in lead V1 of greater than 2.5 mm (5) ST depression in lead II,III and aVF

40. BLOCKS AND MI

41. LAD

42. Inferior MI RCA 1.ST↑ V3R, V4R 2. Ratio of ST↓ V3 to ST↑ III, <0.5 = proximal RCA , 0.5–1.2 = distal RCA 3. S:R wave ratio aVL >3 4. ST↑ III > II 5. ST↓ aVL > I

43. Inferior LCX 1. No ST↓ aVL 2. Ratio of ST↓ V3 to ST↑ III > 1.2 3. S:R wave ratio aVL < 3 4. V4R: ST depression and inverted T wavs 5. ST elevation in posterior leads

44. ACCORDING TO V4R: RCA or LCX

45. LCX

46. RCA

47. SUMMARY Rate Rhythm Axis Intervals Hypertrophy Infarct To summarize: Calculate RATE Determine RHYTHM Determine QRS AXIS Normal Left axis deviation Right axis deviation Right superior axis deviation

48. SUMMARY Rate Rhythm Axis Intervals Hypertrophy Infarct To summarize: Calculate RATE Determine RHYTHM Determine QRS AXIS Calculate INTERVALS PR QRS QT

49. SUMMARY Rate Rhythm Axis Intervals Hypertrophy Infarct To summarize: Calculate RATE Determine RHYTHM Determine QRS AXIS Calculate INTERVALS Assess for HYPERTROPHY Right and left atrial enlargement Right and left ventricular hypertrophy

50. SUMMARY Rate Rhythm Axis Intervals Hypertrophy Infarct To summarize: Calculate RATE Determine RHYTHM Determine QRS AXIS Calculate INTERVALS Assess for HYPERTROPHY Look for evidence of INFARCTION Abnormal Q waves ST elevation or depression Peaked, flat or inverted T waves

51. SUMMARY Rate Rhythm Axis Intervals Hypertrophy Infarct To summarize: Calculate RATE Determine RHYTHM Determine QRS AXIS Calculate INTERVALS Assess for HYPERTROPHY Look for evidence of INFARCTION Now to finish this module lets analyze a 12-lead ECG!

52. 27

53. 27- pericaditis

54. 26

55. 26- Dextrocardia

56. Detect errors Lead I + ve normally If Lead I – ve + - ve aVR with normal R progression  Missed lead If Lead I – ve + + ve aVR with poor R progression  dextrocardia If Lead I + ve with poor R progression think about  AMI, DCM, HTN If V1 R tall  (dextrocardia, postMI , WPW A, RBBB, RVH)

57. 25

58. 25- Missed lead If Lead I – ve with normal R progression

59. 24

60. 24 Normal

61. 23

62. 23

63. 23

64. 22-

65. 22-S brady

66. 21-

67. 21-S tachy

68. 20

69. 20-PVCs Etiology: One or more ventricular cells are depolarizing and the impulses are abnormally conducting through the ventricles.

70. 19

71. AFib

72. 18

73. Rhythm #18 60 bpm Rate? Regularity? regular normal 0.08 s P waves? PR interval? 0.36 s QRS duration? Interpretation? 1st Degree AV Block

74. 17

75. Rhythm #17 50 bpm Rate? Regularity? regularly irregular nl , but 4th no QRS 0.08 s P waves? PR interval? lengthens QRS duration? Interpretation? 2nd Degree AV Block, Type I

76. 18-2nd Degree AV Block, Type I Deviation from NSR PR interval progressively lengthens, then the impulse is completely blocked (P wave not followed by QRS).

77. 17

78. Rhythm #17 40 bpm Rate? Regularity? regular nl , 2 of 3 no QRS 0.08 s P waves? PR interval? 0.14 s QRS duration? Interpretation? 2nd Degree AV Block, Type II

79. 17-2nd Degree AV Block, Type II Deviation from NSR Occasional P waves are completely blocked (P wave not followed by QRS).

80. 16

81. 16-3rd Degree AV Block

82. 15

83. 15-Interpretation Yes , this person is having an acute anterior wall myocardial infarction.

84. 14-Putting it all Together

85. 14-Inferior Wall MI This is an inferior MI. Note the ST elevation in leads II, III and aVF.

86. 13

87. 13-Anterolateral MI This person’s MI involves both the anterior wall (V 2 -V 4 ) and the lateral wall (V 5 -V 6 , I, and aVL)!

88. 12

89. 12-Left Ventricular Hypertrophy

90. ECG Diagnostic Criteria for LVH Sensitivity Specificity Sokolow -Lyon Index SV1 + (RV5 or RV6)>35mm 22 100 Cornell Voltage Criteria SV3+RaVL>28 mm (men), 20mm(women) 42 96 R1 + SIII>25 mm 11 100 R in aVL > 11mm 11 100 Other Criteria include Romhilt and Estes Point Score System Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; 2005.

91. 11

92. 11 Pulmonary Embolism Clues: Sinus tachycardia S1Q3T3 pattern Incomplete RBBB with R precordial T wave inversions

93. 10

94. 10-Ant Inf MI Anterior-inferior STEMI ST elevation is present throughout the precordial and inferior leads. There are hyperacute T waves, most prominent in V1-3. Q waves are forming in V1-3, as well as leads III and aVF . This pattern is suggestive of occlusion occurring in “type III” or “wraparound” LAD (i.e. one that wraps around the cardiac apex to supply the inferior wall)

95. 9

96. 9-Posterior MI

97. 8

98. 8 extensive Anterior STEMI (acute) ST elevation in V1-6 plus I and aVL (most marked in V2-4). Minimal reciprocal ST depression in III and aVF . Q waves in V1-2, reduced R wave height (a Q-wave equivalent) in V3-4. There is a premature ventricular complex (PVC) with “R on T’ phenomenon at the end of the ECG; this puts the patient at risk for malignant ventricular arrhythmias.

99. 7

100. 7 Extensive anterior MI (“ tombstoning ” pattern) Massive ST elevation with “tombstone” morphology is present throughout the precordial (V1-6) and high lateral leads (I, aVL ). This pattern is seen in proximal LAD occlusion and indicates a large territory infarction with a poor LV ejection fraction and high likelihood of cardiogenic shock and death.

101. 6-A

102. 6-A Inferolateral STEMI. Posterior extension is suggested by: Horizontal ST depression in V1-3 Tall, broad R waves (> 30ms) in V2-3 Dominant R wave (R/S ratio > 1) in V2 Upright T waves in V2-3

103. 6-B

104. 6 Marked ST elevation in V7-9 with Q-wave formation confirms involvement of the posterior wall, making this an inferior-lateral-posterior STEMI (= big territory infarct!).

105. 5

106. 5-LM

107. 4

108. 4-Wellens

109. 3

110. 3-LBBB with acute MI V3: 4/-12= - 0.33

111. 2

112. 2

113. 1

114. 1 BER

115. A 60- year- old woman presents with acute- onset chest pain for 45 minutes with the electrocardiography findings as shown in This ECG. Examination shows heart rate at 105 beats per minute; blood pressure, 95/ 60 mm Hg; increased jugular venous pressure (JVP); clear lungs; and no murmurs or gallops. Which of the following treatments is a class III (evidence or general agreement that the treatment is not useful or effective) indication? Intravenous fluids Dobutamine Nitroglycerin Dopamine

116. A-66-year old man known to have heart failure on Bisoprolol, furosemide, and digoxin presented to you for follow up. His ECG is shown, what is the most likely cause of his ECG finding? Ischemic changes Bisoprolol effect Digoxin effect Left ventricular hypertrophy No answer is true.

117. Atrial ectopic beats

118. Focal atrial tachycardia Focal atrial tachycardia (focal AT) is characterized as a rapid regular rhythm arising from a discrete area within the atria. It occurs in a wide range of clinical conditions, including catecholamine excess, digoxin toxicity, pediatric congenital heart disease, and cardiomyopathy. Focal AT is a regular tachycardia and is often confused with other regular supraventricular tachycardias, specifically re-entry tachycardias, sinus tachycardia, and atrial flutter. It may be difficult to diagnose by ECG alone. The diagnosis of focal AT is usually based on ECG, clinical history, and response to interventions such as vagal maneuvers and adenosine. ECG shows a regular atrial tachycardia with P-wave morphology different from that in sinus tachycardia.

119. Atrial flutter

120. A Fib

121. Orthodromic atrioventricular re-entry tachycardia (AVRT)

122. AVRT

123. WPW

124. Ventricular Tachycardia – Monomorphic VT

125. The patient has NO pulse

126. The patient has NO pulse- PEA

127. V Fib ECG Findings Chaotic irregular deflections of varying amplitude No identifiable P waves, QRS complexes, or T waves Rate 150 to 500 per minute Amplitude decreases with duration (coarse VF -> fine VF)

128. Pericarditis Diffuse ST elevations Typically, no reciprocal changes PR displacement

129. Cardiac Tamponade Tamponade Triad (specific, not sensitive): Sinus tachycardia except in? Low voltage QRS Electrical alternans

130. 210

131. 211 Electrical Alternans

132. Wolff-Parkinson-White WPW Triad : Short PR interval Wide QRS Delta wave