The document provides information on electrocardiogram (ECG or EKG) basics including normal intervals, wave components, lead placements, axis determination, and common arrhythmias. It explains that the ECG provides information on heart rate, rhythm, and tissue health. Examples of various normal and abnormal rhythms are presented.

1. A. Bornstein, M.D., F.A.C.C.
Basics of ECG Interpretation
A. Bornstein, M.D., F.A.C.C.
Assistant Professor of Medical Education
Hofstra North Shore-LIJ School of Medicine
Hempstead, NY
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2. A. Bornstein, M.D., F.A.C.C.
Electrocardiogram Intervals: P-QRS-T-U
P-R interval
.12----------------.20 sec
Q-T interval
0.30 ------------------------------------------------------------0.46 sec
QRS
.8-.12 sec
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3. A. Bornstein, M.D., F.A.C.C.
1) P wave: depolarization of atria
2) QRS complex: depolarization of ventricular muscle
3) T wave: repolarization of ventricular muscle
*Repolarization of atria lies under QRS
What information does the EKG give you?
Rate, rhythm, tissue health
The Surface Electrocardiogram

4. A. Bornstein, M.D., F.A.C.C.
Why are there 12 leads shown?
Why is this considered a normal EKG?
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5. A. Bornstein, M.D., F.A.C.C.
Frontal & Precordial Chest Leads
Sensitivity of the lead to measure
the equivalent heart lead vector
around an isopotential source
Hexaxial lead system: unipolar extremity lead axes
bisect the angles of Einthoven's equilateral triangle
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6. A. Bornstein, M.D., F.A.C.C.
What is the importance of the electrical axis?
Averaging all electrical signals from the heart indicates the direction of the
average electrical depolarization with an arrow (vector) = the cardiac axis
Reciprocity theorem: source and detector are interchangeable;
relationship between signals of source and detector remain unchanged
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7. A. Bornstein, M.D., F.A.C.C.
00
Lead I (+)
+900
Lead aVF (+)
Frontal Axis Determination
Normal
axis
LAD
RAD
Northwest
axis
Normal quadrant
(00 to +900)
Normal axis (-300 to +900)
Left axis quadrant
(-10 to -900)
Marked left axis deviation
(> -450)
Right axis quadrant
(+910 to +1800)
Right axis deviation
(+910 to +1800)
Northwest axis quadrant
(-910 to -1800)
Indeterminate axis
(-910 to -1800)
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8. A. Bornstein, M.D., F.A.C.C. ABB MD FACC©
Axial reference system in the frontal plane
Axial reference system
in the horizontal plane

9. A. Bornstein, M.D., F.A.C.C.
Characteristics of the Lead Vector
ECG waveforms result from the mean vector summation of atrial
& ventricular depolarization, which has the following properties:
1) Sense
2) Direction
3) Magnitude
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10. A. Bornstein, M.D., F.A.C.C.
Relationship Between VCG and EKG
Vector Loops
I
A
P
L
R
R
L
S
Frontal Leads Precordial Leads
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11. A. Bornstein, M.D., F.A.C.C.
Positive
deflection
Negative
deflection
Isoelectric
When wave of depolarization moves towards
positive electrode, the deflection is positive
2 Cell Model of EKG Activity

12. A. Bornstein, M.D., F.A.C.C.
ECG Paper

13. A. Bornstein, M.D., F.A.C.C.
ECG Standardization

14. A. Bornstein, M.D., F.A.C.C.
Calculating Heart Rate
1500
# of small boxes between 1 R-R interval
HR =
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Calculating the heart rate: most precise way is to count # of small boxes between
QRS complexes & divide into 1500. Alternatively (easier), cardiac rate can be
determined by counting the number of large squares between cycles & divide
into 300; (i.e., 1 large box between QRS complexes = 300 BPM; 2 large boxes =
150 BPM, etc…)
300
# of large boxes between 1 R-R interval
HR =

15. A. Bornstein, M.D., F.A.C.C.
• ‘Rolls Royces In Seattle Are Pricey Investments.’
7 headings relate to domains of ECG interpretation:
1) ‘Rolls’ = cardiac RHYTHM; relationship between
P wave & QRS; rhythm is classified as regular,
irregular, regularly regular, irregularly irregular.
2) ‘Royces’ = RATE of ventricular response; should be
classified as normal, bradycardia, or tachycardia.
3) ‘In’ = INTERVALS among & between P-QRS-T waves,
compared for consistency among complexes.
4) ‘Seattle’ = SHAPE of wave forms: P wave, QRS, & T;
for RSR, P waves should be consistent from beat to
beat to beat, appear identical, & be associated with
consistent PR interval & QRS complex.
5) ‘Are’ = vector AXIS of QRS complex, T wave,
& P wave. Discordance = pathology or strain on the
heart muscle mass and demands careful evaluation.
6) ‘Pricey’ = PROGRESSION of R-wave in anterior chest
leads. Failure of R-waves to appear progressively
larger, from lead V1 to V6, indicates loss of heart
muscle consistent with MI or other pathology.
7) ‘Investments’ = ISCHEMIA or INFARCTION. features
should be evaluated from an anatomically
geographic perspective from contiguous leads.
Regions include left posterior, inferior heart, septal
aspect, anterior wall, & posterior aspect.
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ECG Interpretation
Patient name:
Date & time:
Paper speed:
Rate: (300, 150, 100, 75, 60, 50, 43, 37,...)
Rhythm:
P waves:
Form:
Axis:
(+) in II & (-) in aVR
PR interval:
QRS:
Duration:
Morphology:
Progression:
Axis:
ST segment:
T wave:
QTc
Special patterns:
MI: (STEMI; Non-STEMI; Anterior; Lateral; Inferior; Posterior)
Interpretation:

16. A. Bornstein, M.D., F.A.C.C.
Sinus Bradycardia
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17. A. Bornstein, M.D., F.A.C.C.
Sinus Tachycardia
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18. A. Bornstein, M.D., F.A.C.C.
Atrial Flutter
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P P P P
P P P P
P P P PPP P P

19. A. Bornstein, M.D., F.A.C.C.
2nd Degree Atrioventricular (Wenckebach) Block
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P P P P P
P P P P P

20. A. Bornstein, M.D., F.A.C.C.
Atrial Fibrillation
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21. A. Bornstein, M.D., F.A.C.C.
Premature Ventricular Contractions
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P PP

22. A. Bornstein, M.D., F.A.C.C.
Ventricular Tachycardia
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23. A. Bornstein, M.D., F.A.C.C.
Ventricular Fibrillation
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24. A. Bornstein, M.D., F.A.C.C.
3rd Degree Atrioventricular Block
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25. A. Bornstein, M.D., F.A.C.C.
3rd Degree Atrioventricular Block
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26. A. Bornstein, M.D., F.A.C.C.
Right Bundle Branch Block
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27. A. Bornstein, M.D., F.A.C.C.
Left Bundle Branch Block (LBBB)

28. A. Bornstein, M.D., F.A.C.C.
Right Ventricular Hypertrophy
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29. A. Bornstein, M.D., F.A.C.C.
Left Ventricular Hypertrophy
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30. A. Bornstein, M.D., F.A.C.C.
EKG Unknown Case 1
A 55 year old male with a history of hypertension, diabetes, presents to the ER with
chest pain, nausea, vomiting, diaphoresis, increasing shortness of breath and dizziness.

31. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 2
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55 year old male presents to ER with palpitations lasting 2 hours associated with substernal chest
pressure. He states that he has intermittently had palpitations for years, but always lasting for
minutes only. Palpitations are now associated with dizziness, shortness of breath and chest pain.
His blood pressure 90/50, heart rate 190 PPM, respiratory rate is 16. No jugular venous distension
is present; he is tachycardic and regular on cardiac exam without any murmurs. His lungs reveals
basilar rales. His ECG is below:

32. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 3
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76 year old male presented with chest pain, nausea, vomiting and diaphoresis.
On physical exam: BP 90/60 mm Hg; HR 50 BPM; RR 16; he has marked JVD at 300
and a right sided S3 gallop; 2+ pedal edema
ECG shows the following:

33. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 3
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76 year old male presented with chest pain, nausea, vomiting and diaphoresis.
On physical exam: BP 90/60 mm Hg; HR 50 BPM; RR 16; he has marked JVD at 300
and a right sided S3 gallop;
ECG shows the following:

34. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 4
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48 year old male with a history spontaneous pneumothorax, who presents with chest pain X 4
hours. On the day of admission, he noticed the onset of chest pain described as bilateral, radiating
to the left arm, worsening over time with some pleuritic component & chest pain worse with
reclining. There is no relation of pain to exertion or meals. No recent trauma.
ECG shows the following:

35. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 5
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50 year old male presents to the ER with sudden onset severe chest pain. The pain is substernal,
worse with deep inspiration, not positional or reproducible, & associated with SOB. Recent past
history is significant for a long flight from China to New York 2 days ago.
Physical exam: BP 90/40, HR 110, RR 28. His O2 saturation is 88% on room air; no JVD is present;
no murmurs; lungs are clear to auscultation. The rest of his exam is normal.
ECG shows the following:

36. A. Bornstein, M.D., F.A.C.C.
EKG and Infarct Location

37. A. Bornstein, M.D., F.A.C.C.
EKG and Infarct Location

38. A. Bornstein, M.D., F.A.C.C.
EKG and Infarct Location

39. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 5
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74 year old male complained of chest pain, then had a v fib arrest. He was resuscitated
and brought to the ED where this ECG was recorded. He was in cardiogenic shock.
ECG shows the following:

40. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 5
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74 year old male complained of chest pain, then had a v fib arrest. He was resuscitated
and brought to the ED where this ECG was recorded. He was in cardiogenic shock.
ECG shows the following:

41. A. Bornstein, M.D., F.A.C.C.
ECG Unknown Case 5
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An adolescent female presented for CP & palpitations with exertion for 3 months. On the day she
presented to the ER, she was running, had the onset of CP, then felt dizzy and almost passed out.
She denies SOB with her pain. She denied family history of sudden cardiac death at a young age, or
for unknown reasons. She is otherwise healthy but has been told that she has a murmur. On exam,
she had a 3/6 systolic murmur that decreased with increasing peripheral vascular resistance.
Here is her ECG:

42. A. Bornstein, M.D., F.A.C.C.
Regular Sinus Rhythm
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