This is presentation of basics of Electrocardiography and its fundamentals specially for beginners of medical professions. The content is intended keeping first year medical professionals as center point.

1. Basics of ECG
Dr. Aniket A. Shilwant
Assistant Professor
Sharir Kriya Dept.
GJPIASR

2. Willem Einthoven
(1860-1927)
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3. Dr.Aniket Shilwant, GJPIASR 3

4. NEW ECG MACHINE
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5. Galvanometer
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6. TABLE OF CONTENTS
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 Basic introduction of ECG
 ECG Paper
 ECG Leads
 ECG Axis
 ECG Wave
 ECG Intervals / Segments (within Physiological limits
only)
 Determination of Heart Rate by ECG
 Wave & Intervals Pathologies

7. Common Terms to get through
while studying ECG
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 Ischemia & Infarction
 Depolarization & Repolarization
 Hypertrophy
 Stenosis
 Incompetence / Regurgitation / Valvular Insufficiency
 Hypertension
 Coarctation of Aorta

8. Basic Introduction of ECG
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 Electrocardiography – Technique or Methodology used
to study of Electrical activities of Heart.
 Electrocardiograph – Graphical presentation of
Electrical activities of Heart.
 Electrocardiogram – Instrument or Machine used to
study the Electrical activities of Heart.

9. Uses of ECG
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 Heart rate
 Heart rhythm
 Chemical or Electrolyte imbalances
 Heart chamber abnormalities
 Defective electrical conduction
 Defective perfusion to Heart musculature (IHD)
 Valve defects

10. ECG PAPER
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 Standard paper divided into 1mm squares of thin lines.
 Every 5th line is thick both horizontally & vertically.
 Speed of paper – two settings / calibrations
 25mm/sec
 50mm/sec

11. ECG PAPER
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X- Axis – Indicates Time Duration – Measured in Seconds
On X- Axis –
1 Small box = 0.04 sec
5 Small box = 0.2 sec
25 Small box = 1 Large box = 1 sec
1500 Small box = 300 Large box = 1 min

12. ECG PAPER
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Y- Axis – Indicates Amplitude (current supply) – Measured
in millivolts
On Y- Axis –
1 Small box = 0.1 mV
5 Small box = 1 Large box = 0.5 mV
10 Small box = 2 Large box = 1 mV

13. ECG LEADS
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 Types of leads based on Polarity & Location
 Classification based on Polarity – Unipolar & Bipolar
 Classification based on Location – Chest & Limb
 Total leads – 12
 Bipolar Limb leads – 03
Lead I, II, III
 Unipolar Limb leads – 03
aVR, aVL, aVF
 Unipolar Chest leads – 06
V1, V2, V3, V4, V5, V6

14. Einthoven Triangle
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15. Lead I
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ECG LEADS – BIPOLAR LIMB LEADS
I – Rt. Arm & Lt. Arm
II – Rt. Arm & Lt. Foot
III – Lt. Arm & Lt. Foot
Rt. Foot – Ground conductor /
Zero electrode / Earthing
electrode

16. Lead II
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ECG LEADS – UNIPOLAR LIMB LEADS
Unipolar Limb Leads –
One electrode is active while other is kept as
indifferent potential.
aVR – Rt. Arm positive
aVL – Lt. Arm positive
aVF – Lt. Foot positive

17. Chest Leads
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ECG LEADS – UNIPOLAR CHEST LEADS

18. Frontal Plane
Horizontal
Plane Dr.Aniket Shilwant, GJPIASR 18
Electrical field covering Heart

19. Normal ECG
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20. ECG – Cardiac Axis
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Cardiac Axis – Cardiac Vector – Direction at
which electrical
potential generated in the heart travels at an
instant.
 Direction of spread of depolarization wave
defines – Cardiac Axis.
 Normal axis – Normal depolarization wave
starts from SA node travels downwards
towards left lower end at apex.
 Normal axis – from 11’O clock – 5’O
clock position
 Cardiac axis deviation indicates mainly –
Ventricular chamber enlargements
& Bundle branch block – conduction
problems

21. Hexa Axial
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22. Dr.Aniket Shilwant, GJPIASR 22
Depolarization at Cardiac Cell
Electrical Pathway

23. Normal Axis
Sr.
No
Lead I Lead III Axis
1 Dominantly +ve Dominantly +ve Normal
2 Dominantly +ve Dominantly -ve Left Axis
3 Dominantly –ve Dominantly +ve Right Axis
4 Dominantly –ve Dominantly -ve Indeterminate Axis
* Left Axis = Left Leaves
* Right Axis = Right Reaches
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24. Left Axis
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Causes for Left Axis -
1. Left Anterior Hemi block
2. Left Ventricular Hypertrophy
3. Inferior wall Myocardial Infarction
4. Apical Pacing

25. Right Axis
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Causes for Right Axis deviation –
1. Left posterior hemi block
2. Right Ventricular Hypotrophy
3. Reversed arm electrodes
4. Dextrocardia

26. ECG Waves
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Normal waves – 5 – PQRST
Rarely 6th wave – U – Clinically Insignificant
 P wave – Atrial complex – Atrial Depolarization
 QRST – Ventricular complex
 QRS – Ventricular depolarization
 T – Ventricular Repolarization
 U – Repolarization of Papillary muscles

27. ECG Waves – P wave
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P wave
 Short, dome shaped, 1st positive wave
 Indicates electrical activity of atria
 Indicates – Atrial depolarization
 Time period – 0.1 sec
 Amplitude – 0.1 – 0.12 mV

28. ECG Waves – QRS Complex
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Q wave
 Short, 1st negative wave
 Indicates depolarization of basal portion of interventricular septum
 May be absent in infants – septal defect.
 Amplitude – 0.1 - 0.2 mV
R wave
 Tall, constant positive wave with high amplitude
 Indicates depolarization of apical portion of interventricular septum
and ventricular musculature
 Amplitude – 1mV
S wave
 Short, negative wave
 Indicates depolarization of basal portion of ventricular musculature
 Amplitude – 0.4mV
 Time period of QRS complex – 0.08 – 0.1 sec

29. QRS Complex Patterns
Progression of QRS pattern in Chest
leads from V1 to V6
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ECG Waves – QRS Complex

30. ECG Waves – T & U Wave
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T wave
 Short, broad, dome shaped positive wave
 Indicates – repolarization of ventricles
 Time period – 0.2 sec
 Amplitude – 0.3 mV
U wave
 Rare and insignificant
 Positive wave Followed after T wave
 Indicates – repolarization of Papillary muscles, Purkinje fibers

31. ECG Intervals / Segments
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Time interval (x-axis = sec) between either onset or end
of any of the two waves – Interval/ Segment
1. PR interval
2. QT interval
3. ST segment
4. RR interval

32. ECG Intervals – PR & QT
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PR interval
 Starts from onset of P wave ends at starting point of Q wave
 Includes only one waveform in it = P wave
 Indicates time taken by impulse to travel from SA node to AV node
 Time period – 0.12sec – 0.2sec
QT interval
 Starts from onset of Q wave ends end point of T wave
 Includes waveforms in it = Q,R,S,T waves
 Indicates complete electrical activity of ventricles (depolarization
and repolarization)
 Time period – 0.40sec – 0.42sec

33. Dr.Aniket Shilwant, GJPIASR 33
ST segment
 Starts where S wave ends and ends at starting point of T wave
 Includes no any waveform in it.
 Normally it is Isoelectric in nature
 Time period – 0.08 sec
RR interval
 Time interval between successive R waves
 Thus it Indicates 1 heart beat.
 Also it indicates 1 complete cardiac cycle.
 Time period – 0.8 sec
ECG Intervals – ST & RR

34. Complete Single ECG Complex
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35. Specifications of Waves & Intervals
of Normal ECG
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Wave Extent Cause
Duration in
seconds
Amplitude in
mV
P wave - Atrial Depolarization 0.1 0.1 to 0.2 mV
QRS
complex
Onset of Q wave to
end of S wave
Ventricular
Depolarization
0.08 to 0.1
Q – 0.1 TO
0.2mV
R – 1mV
S – 0.3mV
T wave -
Ventricular
Repolarization 0.2 0.3mV
PR
interval
End of P wave to onset of
Q wave
Conduction of impulse
from SA to AV node
0.12 – 0.20 -
QT
interval
Onset of Q wave to end
of T wave
Electrical activity of
ventricles
0.4 – 0.42 -
ST
segment
Starts from end of S
wave and ends prior start
of T wave
Isoelectric 0.08 -

36. How to determine Heart rate by
ECG?
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RR Interval (Large squares) Heart rate per min.
01 300
02 150
03 100
04 75
05 60
Count small or large squares between two R waves.
This is nothing but RR interval.
1 small square = 0.04 sec
1 large square = 5 small square = 0.2 sec
5 large square = 25 small square = 1 Sec
300 large square = 1500 small square = 1min
Heart rate = 1500 / N (N is no. of small squares in
between two R waves)
Heart rate = 300 / N (N is no. of large squares in
between two R waves)

37. Dr.Aniket Shilwant, GJPIASR 37
Wave Pathologies

38. P wave
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Look for P wave in Lead II
P wave –
 Absent – Atrial Fibrillation
 Tall, Spiked (Above 2.5mm) –
P Pulmonale – Rt. Atrial
Hypertrophy
 Short, Bifid – P Mitrale – Lt.
Atrial Hypertrophy

39. P wave - RAH & LAH
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Causes for RAH –
 Tricuspid Stenosis
 Pulmonary Hypertension
 Congenital Heart Disease
Causes for LAH –
 Mitral Stenosis
 Mass In the Left Atrium
 Cardiomyopathy

40. RAH
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41. LAH
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42. BIATRIAL HYPERTROPHY
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43. Dr.Aniket Shilwant, GJPIASR 43
 Right ventricular hypertrophy
 Tall R wave in V1, V2 & or Deep S wave in V6
 Right Axis deviation
 Inverted T wave in V1, V2
 Left ventricular hypertrophy
 Tall R wave in V5, V6 & or Deep S wave V1, V2
 Inverted T wave in Lead I, aVL, V5, V6
 Left Axis deviation
 Bundle branch block
 RBBB – RSR’ pattern in V1
 LBBB – RR’ pattern (M pattern) IN V6
QRS Complex Pathologies

44. RVH
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45. LVH
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46. T Wave
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T wave –
 Normally inverted in aVR
 Tall, peaked with high amplitude T wave seen in –
Ischemia
T wave inversion seen in –
 Myocardial Infarction
 Hypokalemia
 Ventricular hypertrophy

47. PR & QT Inetrvals
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PR interval –
Prolonged
 First degree heart block
 Bradycardia
Shortened
 Tachycardia
QT interval –
Prolonged
 Myocardial infarction
 Hypothyroidism
 Hypocalcemia
Shortened
 Hypercalcemia

48. ST Segment
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Elevated
 Anterior / inferior myocardial infarction
 Left bundle branch block
Depressed
 Acute myocardial ischemia
 Hypokalemia
 Ventricular enlargements

49. Relationship
Of the
ECG
To The
Cardiac
Conduction
System
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50. Presentation of ECG Report
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51. Dr.Aniket Shilwant, GJPIASR 51
Dr. Aniket A. Shilwant
Assistant Professor
GJP-IASR
Email – ayuraniket18@gmail.com
http://ayugjac.edu.in/Staff_CV.aspx?dl=dn3Mja19480dn3Mja19
http://scholar.google.co.in/citations?user=636K2sMAAAAJ&hl=en
https://www.researchgate.net/profile/Aniket_Shilwant
Thank you all…!!!