1. EKG 101 (Help, I’m a Doctor!)
Scott Ewing, D.O.
July 5, 2006

11. The EKG Paper
Time intervals indicated for the thick and thin vertical grid lines on the ECG paper are appropriate for the standard paper speed of 25 mm/sec
Amplitudes indicated for the thick and thin horizontal grid lines are appropriate for the standard gain of 10 mm/mV
Each small square is therefore 0.04 s × 0.1 mV, and each large square is 0.20 s × 0.5 mV

12. Normal EKG
Normal individual's 12-standard ECG leads are presented in the classical format of four columns consisting of three leads each
Arrows indicate the small Q waves that may normally occur in leads I, II, aVL, V4, V5, and V6
Asterisk in lead V3 indicates the minute Q wave that may rarely occur normally

13. Rate

14. Rhythm

15. Axis Normal axis (NA) Right-axis deviation (RAD)
Left-axis deviation (LAD)
Extreme axis deviation (EAD)
+60 degrees
+150 degrees
–30 degrees
–60 degrees
–120 degrees

16. P Wave

17. PR Interval

18. QRS Complex

19. ST Segment

20. Normal R Wave Progression
Typical panoramic display of the six precordial leads of the ECG, illustrating the normal progression and regression of R- and S-wave amplitudes

21. Normal QRS Complex 25-year-old normal woman
48-year-old man with acute chest pain of noncardiac origin
54-year-old woman with acute chest pain of noncardiac origin
20-year-old normal man
63-year-old man with aortic valve disease

22. Acute Ischemia – ST Depression

23. Acute Ischemia – ST Depression

24. Acute Ischemia – ST Depression

25. Acute Ischemia - T Wave Changes

26. Infarct - ST Elevation

27. Inferior Infarct – ST Elevation

28. Inferior Infarct – ST Elevation

29. Posterior Infarct – ST Elevation!!!

30. Old Infarct - Anterior Q Waves

31. Old Infarct - Inferior Q Waves

32. Persistent ST Changes

33. Persistent T Wave Changes

34. 34 Year Old Male With Chest Pain

35. 60-year-old Male

36. Anterior Ischemia
ECG shows sinus rhythm with ventricular ectopy, left axis deviation, consistent with left anterior fascicular block (hemiblock), and T wave inversions in V2-V5 with subtle upward bowing of the ST segments
ST-T abnormalities in I and aVL
Symmetric T wave inversions, especially with upward bowing of the ST segments is highly suggestive of ischemia in the left anterior descending distribution (LAD) in this context
Most expeditious test to order is a cardiac catheterization, which showed significant LAD (and obtuse marginal) disease

37. Elderly Male

38. Severe Ischemia
ECG shows sinus rhythm at about 65 bpm with profound ischemic ST segment depression, most marked in the precordial leads, consistent with severe subendocardial ischemia and probable non-Q wave myocardial infarction
QT interval is not prolonged (0.41 second at rate of 65 bpm) and the PR interval is at the upper limits of normal (0.20 second)
Broad P waves are present (biphasic in lead V1) consistent with left atrial abnormality
Q waves in the infero-lateral leads are consistent with prior myocardial infarction(s)
Profound ST depressions of this type usually indicate severe multivessel disease, and sometimes left main coronary disease
The patient experienced severe chest pain and was transferred from an outside facility in cardiogenic shock
En route to the cardiac catheterization laboratory, he developed refractory pulseless electrical activity and ventricular fibrillation.

39. 84-year-old Female

40. NQWMI
ECG shows left ventricular hypertrophy (LVH) plus left atrial abnormality (LAA)
QRS axis is somewhat leftward (-7 degrees)
Although LVH alone may be associated with ST-T abnormalities (sometimes referred to as a "strain pattern"), like those in lead aVL, the prominent horizontal or downsloping ST depressions in other leads (I, II, aVF, V5, V6) here are strongly suggestive of ischemia superimposed on LVH
The patient had positive cardiac enzymes and underwent cardiac catheterization showing left main and three vessel coronary disease, followed by coronary artery bypass graft surgery.

41. 34-year-old male

42. Acute Anterior MI
Classic findings of acute anterior wall Q wave myocardial infarction
Reciprocal inferior ST depressions
Hyperacute T waves
Distribution of changes is consistent with a proximal LAD occlusion
Confirmed at cardiac catheterization and treated with PTCA and stenting
Premature atherosclerosis with multiple risk factors including hypertension, hyperlipidemia, family history and tobacco.

43. 68-year-old female

44. Acute Anterior MI Note Q waves and loss of R waves V1 - V4
ST elevation in V2 - V5/V6
Left anterior fascicular block is also present, but does not account for the loss of R wave progression
The patient had had a very recent anterior MI
Cardiac catheterization revealed 3-vessel disease with a 90% mid-LAD "culprit" lesion

45. 53-year-old female

46. Acute Lateral MI ST elevations in I and aVL
Probable reciprocal ST depressions inferiorly consistent with acute lateral MI
Remember: ST elevations like this are never reciprocal but indicate the primary region of ischemia (diagonal or circumflex lesion)
Confirmed left circumflex occlusion at catheterization

47. 36-year-old male

48. Acute Pericarditis
Always consider myocardial infarction first when you see ST elevations
But don't forget the differential diagnosis of ST elevations
Ischemic heart disease
Pericarditis
Left bundle branch block (LBBB)
Normal ("early repolarization") variant
Two features here point to pericarditis
First, diffuseness of the ST elevations (I, II, III, aVF, V3-V6)
Second, PR depression in II, aVF, V4-V6 and PR elevation seen in aVR (attributed to subepicardial atrial injury)

49. 49-year-old male

50. Acute Pericarditis Diffuse ST segment elevations (I, II, aVF, V2-V6)
Subtle PR segment deviations (elevated in aVR and depressed in the inferolateral leads)
ST elevations are due to a ventricular current of injury from the pericardial inflammation
PR changes are due to an associated atrial current of injury
Note that the PR and ST segment vectors point in opposite directions, i.e., PR up and ST down in aVR and PR down and ST up in inferolateral leads
Resting sinus tachycardia is noted. The patient had a fever but no pericardial effusion

51. Middle aged female

52. Acute Myocardial Infarction
Marked inferior and lateral ST segment elevation
ST segment depression in anterior leads V1-V4
ST elevations (“current of injury” pattern) indicate transmural ischemia of the infero-lateral wall
ST depression most consistent with reciprocal change from the ST elevation generated by the acute posterior and lateral ischemia
Remember, acute pericarditis causes diffuse ST segment elevation (e.g., leads I, II, III, aVL, aVF, and the precordial leads)
Reciprocal ST depressions of the type seen here (V1-V4), are never a feature of pericarditis alone
Cardiac catheterization revealed acute occlusion of a dominant left circumflex coronary artery (along with occlusion of a smaller RCA)