This document provides an overview of ECG interpretation. It discusses key elements like rhythm, axis, intervals, complexes and segments. Specific conditions are highlighted like inferior posterior STEMI and RV infarct. The importance of systematic analysis is emphasized. Pattern recognition, trends over serial ECGs and correlating findings with the clinical scenario are important skills. Confirming posterior STEMI with lateral precordial lead placement is advised. Overall it is a comprehensive guide to the fundamentals of ECG interpretation and applications in patient care.

1. ECG 101

2. ECG 101
Inferior posterior STEMI
Likely RV infarct
Avoid GTN and morphine
May need a fluid load

3. The eyes may be the window to the
soul
But the ECG is the window to the heart,
lungs, toxicology, electrolytes, body
temperature and sometimes even the
brain

4. Pattern recognition

6. An ECG is put under your nose
Immediately
Interpret
Time
Name stamp
Covers nurse/HCA’s arse
Makes you read it
We know who to educate if it’s wrong

7. Be systematic
One system

8. Patient’s name
Presenting complaint

9. ECG machine
RR interval big squares: 300, 150, 100, 75, 60, 50
total number of complexes across the page x 6
Rate

10. ECG machine
RR interval big squares: 300, 150, 100, 75, 60, 50
total number of complexes across the page x 6
Rate
SVT

11. Rhythm

12. Rhythm
Atrial flutter with 2:1 block
Atrial flutter with 2:1 block

13. Same patient after
treatment for sepsis
A
Atrial flutter with variable block

14. Frontal axis

15. Frontal axis
h R atrial abnormality (P pulmonary) and extr

16. Why else do we care
about axis?
CQC

17. Why else do we care
about axis?
CQC
Incomplete Trifasicular block:
RBBB, LAD and 1˚HB

18. Incomplete trifascilar block
RBBB, LAD and 1˚HB
1 myocyte away from complete heart block
Don’t send this post syncope patient home

19. Then proceed through
the complexes

20. p waves

21. p waves
P mitrale: mitral stenosis

22. PR interval

23. PR interval
1˚HB
Lown-Ganong-Levine syndrome
with short PR interval
Mobitz type 2 2˚HB
PR depression II, V5, V6,
PR elevation aVR
Saddle shaped ST elevation II, v5, V6
Inverted saddle shaped ST elevation aVR
= pericarditits

25. QRS complex

26. QRS complex
Wide complex tachy, probably VT
LBBB
RBBB

27. QRS complex

28. QRS complex
Hyperkalaemia
Sodium channel blockade
eg tricyclic overdose

29. QRS complex

30. QRS complex
Severe hyperkalaemia

31. Killer Qs
Pathological Qs
> 40 ms (1 mm) wide
> 2 mm deep
> 25% of depth of QRS complex
Seen in leads V1-3

32. Killer Qs
Pathological Qs
> 40 ms (1 mm) wide
> 2 mm deep
> 25% of depth of QRS complex
Seen in leads V1-3
Q waves 2˚ to MI
May still be thrombolysable
HOCM

33. ST segment

34. ST segment
LBBB
LVHBrugada

36. ST
segment
R

37. ST
segment
R
Right ventricular infarct
Posterior STEMI

38. ST segment

39. ST segment
Inferior-posterior-high lateral STEMI

40. ST
segment

41. ST
segment
Paced rhythm with Sgarbossa
+ve anterior ST depression and
> 5mm ST elevation in III
LBBB

42. Original Sgarbossa Criteria
Concordant ST-segment elevation ≥ 1 mm in any lead (5 points)
oncordant ST-segment depression ≥ 1 mm in lead V1 – V3 (3 poin
Discordant ST-segment elevation ≥ 5 mm in any lead (2 points)

43. ST segment

44. ST segment
Critical left main coronary occlusion or
extensive triple vessel disease
avoid clopidogrel

45. T waves

46. T waves
Hyperactue Ts in ischaemia
Wellens’ Type A
Wellen’s type B

47. Repeat
ECGs
13 minutes later, pain free:

48. Repeat
ECGs
Same patient 13 minutes later, pain free:
Biphasic T in V2
T wave inversion aVL
Deep anterior T wave inversion
Wellen’s syndrome (type B)
Don’t put a Wellen’s patient on a treadmill
they tend to drop dead

49. T waves

50. T wavesAnterior and inferior TWI
Right heart strain
PE
Lateral T wave inversion due to LVH
Lateral T wave inversion due to LBBB

51. T waves

52. T wavesAnterior and lateral
T wave inversion
HOCM
Flattened T waves
Ischaemia

53. T waves

54. T waves
Lateral and high lateral
T wave inversion
due to ischaemia
T wave inversion due to
subarachnoid haemorrhage
(rare)
Hyperkalaemia

55. QTc
Long QT syndrome (genetic)
Drugs incl amiodarone, digoxin, macrolides,
antipsychotics, tricyclics, SSRIs, loratidine
Hypothermia
HyperCa
HypoK, hypoMag
Myocardial ischaemia
ICH
+ others
> 440ms in men or
> 460ms in women

56. QTc
Long QT syndrome (genetic)
Drugs incl amiodarone, digoxin, macrolides,
antipsychotics, tricyclics, SSRIs, loratidine
Hypothermia
HyperCa
HypoK, hypoMag
Myocardial ischaemia
ICH
+ others
> 440ms in men or
> 460ms in women
Prolonged QT
Prolonged QT
leading to
Torsades de pointes

57. Just to reinforce …

58. Just to reinforce …
Anterior-septal marked ST depression
(reciprocal ST elevation)
and prominent S R waves
(reciprocal Qs)
=probable posterior STEMI

59. Posterior STEMI

60. Posterior STEMI
Confirm by moving V4-6
to the posterior chest

61. Methodical read
Record your interpretation
Time
Name stamp
Further actions esp
repeat ECGs q10min x 3 for CP
eg Trodat Printy 4910
http://www.selfinkingstamps.co.nz/shop/trodat-4910-26x9mm/
$20 delivered

62. References and images
Most facts checked with and images obtained from
Life in The Fast Lane
http://lifeinthefastlane.com/