1. Remove the Mystery from 12 Lead EKG Interpretation for Acute MI
The simple, rapid “12 lead solution” to 12 lead confusion!
A 12 Lead Program for ALL health care professionals!
Copyright Apex Innovations 2003

2. The Basics….. Let’s do the re-view
Coronary Anatomy
Conduction
Paper and rate basics
Rhythm
Lead placement
Vectors and axis
R wave progression

3. Coronary Anatomy Aorta Circumflex (Cx) Right Coronary Artery (RCA)
Left Anterior
Decending (LAD)

4. Constant, Continuous Conduction….the beat goes on
Normal P-QRS-T
Constant, Continuous Conduction….the beat goes on
QRS..
Ventricular
depolarization
P wave
Depolarization &
contraction of
both atria
Iso-electric Line
T wave…
Ventricular
repolarization

5. Constant, Continuous Conduction….the beat goes on
Normal P-QRS-T
Constant, Continuous Conduction….the beat goes on
R-Upward slope
S-Down slope
Iso-electric Line
Q-First down slope

6. Normal P-QRS-T P Wave PR Interval QRS Complex ST Segment Represents
Atrial
depolarization
Time between onset of atrial depolarization and onset of ventricular depolarization
(AV conduction time)
Ventricular depolarization
Interval between ventricular depolarization and repolarization
Duration
< 0.12 seconds
seconds
seconds
Measure from end of QRS to
J-point, the beginning of T wave
Height
< 2.5 mm
Measure start of P wave
to start of QRS
Q- First negative
deflection
R- First positive
S- Negative deflection
after R wave
Shape
Smooth
Prolonged indicates a conduction block
Shortened indicates accelerated conduction or junctional in origin
In relation to iso-electric line:
Depression/Negative indicates ischemia
Elevation/Positive indicates injury
Orientation
Positive in Leads I,II,aVF, V4
Negative in aVR

7. Cardiac Conduction System
Sinus node
Internodal
pathways
AV node
Left
Bundle
Branch
Bundle of His
Right
Bundle
Branch
Purkinje
fibers

8. Cardiac Conduction System
Relationship of ECG to anatomy

9. Rate: EKG Paper Basics
Standard paper speed = 25mm per second Note calibration on side of EKG - 2 Large Blocks tall
One small Block = 1mm Voltage
One Small Block = .04 Seconds
One Large Block = 5mm Voltage
One Large Block = .20 Seconds
-Increased paper speed makes complexes wider -Decreased paper speed makes the complexes narrower

10. Rate: Calculation Options
RATE = # of R waves in a 6 second strip X 10
RATE = 300  # large squares between R waves
RATE Count = Count from a QRS complex on any bold line to the next QRS complex. Count “300, 150, 100, 75, 60, 50” for each bold line after first complex.
Start
End
Rate = 82 BPM

11. Rhythms Sinus (SA Node) Normal Sinus Sinus Bradycardia
Sinus Tachycardia
Sinus Arrhythmia
Sick Sinus Syndrome
Wandering Atrial Pacemaker
Sinus Block
Sinus Arrest

12. Rhythms Continued Atrial Rhythms Premature Atrial Contraction (PAC)
Paroxysmal Atrial Tachycardia (PAT)
Multifocal Atrial Tachycardia
Atrial Flutter
Atrial Fibrillation

13. Rhythms Continued Junctional (AV)
Premature Junctional Contraction (PJC)
Paroxysmal Junctional Tachycardia (PJT)
Junctional Flutter
Junctional Fibrillation

14. Rhythms Continued Ventricular Premature Ventricular Contraction (PVC)
- Bigeminy Trigeminy, Quadrageminy
Paroxysmal Ventricular Tachycardia (PVT)
Multifocal Ventricular Tachycardia
Ventricular Flutter
Ventricular Fibrillation

15. Rhythms Continued AV Blocks 1 Prolonged PRI 2 Type I - Wenchebach
2 Type II - Mobitz II
- 2:1, 3:1 Conduction
3 Complete Heart Block
Bundle Branch
- Right BB
- Left BB

16. The 12 Lead EKG… 12 angles or pictures
of the electrical activity of the heart
6 Limb Leads
6 Chest or Pre-cordial Leads I II
III
AVR
AVL
AVF V1 V2 V3 V4 V5 V6

17. Looking and Learning: Vectors and Axis ~the hard way~
The sum of all vectors determines the axis
A panoramic view
of the heart’s
electrical activity from
12 different angles

18. Lead Placement - Lead I, II, III
LEAD I Bipolar Limb Lead
Looks from Right to Left Shoulder
Looks at high lateral wall of
left ventricle
Supplied by circumflex artery–CX
Positive/upright P QRS T - RA + LA LL

19. Lead Placement - Lead I, II, III
LEAD II Bipolar Limb Lead
Looks from R Shoulder to Left Leg
Looks at inferior wall of left ventricle
Supplied by right coronary artery–RCA
Positive/upright P QRS T - RA + LA - + LL

20. Lead Placement - Lead I, II, III
LEAD III Bipolar Limb Lead
Looks from Left Shoulder to Left Leg
Looks at inferior wall of left ventricle
Supplied by right coronary artery-RCA
A biphasic QRS complex is expected - RA + LA - - + + LL

21. Augmented Limb Leads AVR AVL Augmented Voltage Left Arm AVF
Augmented Voltage Right Arm
All complex waves are negative
Typically, this lead not used for diagnosing!
AVL
Augmented Voltage Left Arm
Looks at lateral wall of left ventricle
Supplied by circumflex artery - CX
All complexes should be positive
AVF
Augmented Voltage (left) Foot
Cross between Leads I and II
Looks at inferior wall of left ventricle
Supplied by right coronary artery-RCA RA LA + + + LL

22. Lead Placement – V-Leads
V1-V2 = Septal
V3-V4 = Anterior
V5-V6 = Lateral
V1-V3 = Posterior
V1 – 4th ICS, right of sternum
V2 – 4th ICS, left of sternum
V3 – Midpoint between V2 and V4
V4 – 5th ICS, mid-clavicular line
V5 – Level with V4 , anterior to axillary line
V6 – Level with V4, mid-axillary line

23. V-Lead R Wave Progression
The progression or increasing in R wave amplitude from negative to positive in leads V1 to V4 is expected and normal!
- V1 - R wave is generally smallest or most negative
- V4 - R wave is typically the tallest or most positive
- Lack of R wave progression may mean :
Pathology- Disease state, CAD, Septal wall MI
Normal- A patient with Congenital state, Rotated heart, Obesity, COPD
Other- Breast tissue, poor lead placement

24. R Wave Progression in the V Leads
V1 – PQRST All negative
V2 – PQRST Should be mostly negative but
start progression
V3 – PQRST Biphasic with upright T waves
V4 – PQRST Nearly completely upright
V5 – PQRST Upright
V6 – PQRST Upright

25. Myocardial Infarction
Bumps, elevations and tombstones…
Ischemia
Injury
Recognition
Criteria
Infarct Location Template
AMI Evolution
Practice EKG’s

26. Myocardial Infarction
Occurs when a coronary artery is narrowed and occludes,
terminating the blood and oxygen supply. This results in
cardiac hypoxia and irritability which may cause fatal arrhythmias.
Without a blood supply to the cardiac muscle, depolarization
cannot happen and renders the muscle, electrically dead.
An EKG can diagnose AMI location, identify the culprit
artery and reveal any blocks in
ventricular conduction.

27. ST Depression = Ischemia
Inverted T waves, sometimes peaked
T wave deflection is opposite from QRS (Normally T wave is upright when QRS is upright and vice versa)
T wave inversion is usually in same leads that demonstrates signs of acute infarction
(Q waves, ST elevation)

28. Causes for ST depression
Ischemia
Digoxin Toxicity
Pulmonary Embolism
Ventricular Hypertrophy
Left Bundle Branch Block

29. ST Elevation = Current Injury
Depicts current myocardial injury
Measure J-point to beginning of ventricular repolarization
May be elevated >1mm in limb leads and >2mm in precordial leads
Will see reciprocal ST depression in other leads

30. Causes for ST elevation
Pericarditis
Ventricular aneurysm
Drug induced
Myocardial Infarction

31. Recognition of AMI Know what to look for: ST elevation >1 mm
J point
Know what to look for:
ST elevation >1 mm
3 contiguous leads
PR baseline
ST-segment deviation = 4.5 mm

32. AMI  Requires at least 2 of these criteria:
History of characteristic chest pain
Crushing-pressure in chest, pain radiation to jaw, arms, back, N/V, SOB, diaphoresis
Evolutionary EKG changes
ST depression (ischemia)
ST elevation (injury)
Q wave development (muscle death)
Elevated cardiac enzymes
Troponin, CKMB-CK, Myoglobin

33. Understanding infarct location Here’s the trick!
The 12 Lead Solution to
12 Lead Confusion!

34. Location, Location, Location!
Simple - Rapid!!
Finally…….
Remove the mystery!
Location, Location, Location!

35. AMI Location Correlation
I Lateral
aVR
V1 Septal
V4 Anterior
This slide illustrates the 3  4 format of the 12-lead ECG.
Each box represents 1 lead, and the viewpoint of that lead is indicated.
II Inferior
aVL Lateral
V2 Septal
V5 Lateral
III Inferior
aVF Inferior
V3 Anterior
V6 Lateral

36. Lateral Lead ST Elevation in AMI
LEAD I
AVL V5 V6
 “High Lateral” Wall 
Lateral: Usually supplied by Circumflex (CX)
Look for reciprocal changes in Lead V1

37. Normal EKG
Lateral
Reciprocal
Change
Lateral
Lateral
Lateral

38. Inferior Lead ST Elevation in AMI
LEAD II
LEAD III
AVF
Inferior: Usually supplied by Right Coronary Artery (RCA)
Look for reciprocal changes in Leads I, AVL

39. Normal EKG Reciprocal Change Inferior Reciprocal Change Inferior

40. Septal Lead ST Elevation in AMI
Septal: Usually supplied by Left Anterior Descending (LAD)
Look for reciprocal changes in Leads V3, AVF

41. Normal EKG
Septal
Septal
Reciprocal Change
Reciprocal Change

42. Anterior Lead ST Elevation in AMI
Usually supplied by Left Anterior Descending (LAD)
Look for reciprocal changes in Leads V2, AVF

43. Normal EKG
Anterior
Reciprocal Change
Reciprocal Change
Anterior

44. 12 Lead-Paper Heart To better understand rhythm location:
Hold left upper corner and
right lower corner of EKG
Roll EKG to note:
inferior leads at apex
lateral leads on sides
anterior and septal leads in front

45. Significant Q Wave Characteristics
Height is 1/3 the size of entire
QRS complex
Width is at least one square or
0.04 seconds in duration
Q waves in V1,V2,V3 or V4
indicate anterior or antero-
septal infarction
Damage from old infarcts cause
Q waves that last a lifetime
Abnormal if thick on tracing
Q wave may be normal in AVR

46. ST segment Evolution and Q wave development with AMI

47. Differentiating Between Acute and Old MI
Q wave with no other morphology = old MI
Q wave and ST segment elevation (with or without T wave inversion) = AMI
Q wave and inverted T wave = age undetermined

48. Evolutional Changes of an Acute Myocardial Infarction

49. Identify infarct location using a systematic approach
Rhythm
ST Depression
ST Elevation
R Wave Progression
Q Waves

50. Let’s take a look at… the Good, the Bad and the Ugly! ~EKG Review~

51. Review #1 What Does This 12-Lead ECG Show?
INFERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

52. Review #2 What Does This 12-Lead ECG Show?
LATERAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

53. Review #3 What Does This 12-Lead ECG Show?
LATERAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

54. Appearances and History are Important!
Your patient, a 58 y/o male, was diagnosed with cancer 2 weeks ago and was scheduled to receive his first chemotherapy treatment this morning. Instead, he was delivered in a wheelchair hurriedly (by his oncologist), to the emergency department in distress. He presents complaining of intense chest pain described as a “10”, is very restless, nauseated, diaphoretic and pale. You order the usual cardiac work-up. Here is what his EKG showed…

55. Review #4 What Does This 12-Lead ECG Show?
LATERAL
SEPTAL
ANTERIOR
INFERIOR

56. Later that day…
This patient’s cardiac workup returned within normal limits and was diagnosed with anxiety and released to begin his chemotherapy.

57. Review #5 What Does This 12-Lead ECG Show?
LATERAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

58. Review #6 What Does This 12-Lead ECG Show?
INFERIOR
LATERAL
LATERAL
SEPTAL
ANTERIOR
INFERIOR

59. Review #7 What Does This 12-Lead ECG Show?
LATERAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

60. Appearances and History are Important!
Your patient, a 62 year old male pharmacist, presents at 6:00AM with chest pressure radiating to his neck, jaw and left arm. He is mildly short of breath and says he’s had indigestion all night. You order the usual cardiac work-up. Here is what his EKG showed…

61. Review #8 What Does This 12-Lead ECG Show?
LATERAL
SEPTAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

62. Later that day… The Inferolateral/Anteroseptal MI
caused massive injury and tissue death,
and the patient subsequently died.

63. Review #9 What Does This 12-Lead ECG Show?
INFERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

64. Review #10 What Does This 12-Lead ECG Show?
SEPTAL
LATERAL
SEPTAL
ANTERIOR
INFERIOR

65. Posterior MI’s can be tricky!
EKG changes are seen in V1-V3 (the anterior precordial leads)
and are a mirror image of an anteroseptal MI
You will see:
Increased R wave amplitude and duration
R wave is more prominent than S wave in V1 and V2
ST depression and large inverted T waves V1-V3
Posterior MI HINT: R waves in V1 and V2?
Suspect Posterior MI!

66. Review #11 What Does This 12-Lead ECG Show?
POSTERIOR
LATERAL
SEPTAL?
ANTERIOR
INFERIOR
ANTERIOR?

67. Review #12 What Does This 12-Lead ECG Show? Look at those R waves!!!
POSTERIOR
INFERIOR
LATERAL
SEPTAL?
ANTERIOR
INFERIOR
ANTERIOR?

68. Tick-Tock
~~ Time is Muscle! ~~

69. Please stop here! ~Test Time~ Answer the Self Assessment Sheet’s
first 8 questions.
2. Next proceed to the remaining
slides and record the infarct location
for each EKG on the self assessment.

70. Quiz #1 Where is the elevation or infarct?
LATERAL
SEPTAL
ANTERIOR
INFERIOR
INFERIOR

71. Quiz #2 Where is the elevation or infarct?
SEPTAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

72. Quiz #3 Where is the elevation or infarct?
LATERAL
LATERAL
SEPTAL
ANTERIOR
INFERIOR

73. Quiz #4 Where is the elevation or infarct?
SEPTAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR
Review the 12-lead ECG.
Go lead by lead, and pick one good complex in each lead.
Find the J point and ST segment.
Compare the ST to the TP segment, looking for 1 mm (1 small box) of elevation (ignore ST depression for now).
Place a check mark next to any lead with 1 mm of ST-segment elevation.
Localize the area of infarction.

74. Quiz #5 Where is the elevation or infarct?
LATERAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

75. Quiz #6 Where is the elevation or infarct?
SEPTAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

76. Quiz #7 Where is the elevation or infarct?
INFERIOR
LATERAL
LATERAL
SEPTAL
ANTERIOR
INFERIOR

77. Quiz #8 Where is the elevation or infarct?
LATERAL
SEPTAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

78. Quiz #9 Where is the elevation or infarct?
SEPTAL
LATERAL
SEPTAL
ANTERIOR
INFERIOR

79. Quiz #10 Where is the elevation or infarct?
LATERAL
ANTERIOR
INFERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

80. Quiz #11 Where is the elevation or infarct?
SEPTAL
ANTERIOR
LATERAL
SEPTAL
ANTERIOR
INFERIOR

81. Thank you for your participation!
Please complete the program and speaker evaluation.
Copyright Apex Innovations 2003