Help in understanding the basics of ECG

1. PRESENTED BY:
Ahmed Sarteel Al-Shammary
THE BASICS OF EKG

2. INRODUCTION
ECG or EKG
ECG is essential for diagnosis
Essential in management of cardiac rhythm
Helps in diagnosis of chest pain
Proper use of thrombolysis in treatment of MI depend
upon it

3. HISTORY
1842- Italian scientist Carlo Matteucci realizes that
electricity is associated with the heart beat
1872- French scientist Gabriel Lippmann , invented the
capillary electrometer which can measure electricity by
utilizing mercury
1876- Irish scientist Marey analyzes the electric pattern of
frog’s heart

4. CONTD…
1895 - William Einthoven , credited for the invention of
EKG
1906 - using the string electrometer EKG,
William Einthoven diagnoses some heart problems
1924 - the noble prize for physiology or medicine is given to
William Einthoven for his work on EKG

6. MODERN ECG INSTRUMENT

7. ELECTRICITY OF HEART
Contraction of any muscle is associated with electrical
charges called depolarization
These changes can be detected by electrodes attached to
the surface of the body
Although the heart has 4 chambers, from the electrical
point it is having only 2

8. THE WIRING DIAGRAM OF
THE HEART
• SA
• AV node
• Bundle of His
• Bundle branches (left and right)

9. THE SHAPE OF ECG
• Contraction of atria - P wave
Ventricular depolarization - QRS complex
Ventricular repolarization - T wave

10. NORMAL ECG

11. ECG INTERPRETATION

12. RELATIONSHIP BETWEEN THE NUMBER OF
LARGE SQUARES COVERED BY R-R INTERVAL
AND THE HEART RATE
R-R INTERVAL(large squares) HEART RATE (beats/min)
1 300
2 150
3 100
4 75
5 60
6 50

13. ECG RHYTHM

14. NORMAL SINUS RHYTHM
Looking at the ECG you'll see that:-
• RHYTHM - Regular
• RATE - (60-100 bpm)
• QRS DURATION - Normal
• P WAVE - Visible before each QRS complex
• P-R INTERVAL - Normal (<5 small Squares. Anything
above and this would be 1st degree
block)
• Indicates that the electrical signal is generated by the sinus
node and travelling in a normal fashion in the heart.

15. NORMAL SINUS RHYTHM

16. SINUS BRADYCARDIA
Looking at the ECG you'll see that:-
• RHYTHM - Regular
• RATE - Less than 60 beats per minute
• QRS DURATION - Normal
• P WAVE - Visible before each QRS
complex
• P-R INTERVAL - Normal
• Usually benign and often caused by patients on beta
blockers

17. SINUS BRADYCARDIA

18. SINUS TACHYCARDIA
Looking at the ECG you'll see that:-
• RHYTHM - Regular
• RATE - More than 100 beats per minute
• QRS DURATION - Normal
• P WAVE - Visible before each QRS complex
• P-R INTERVAL - Normal
• The impulse generating the heart beats are normal, but they
are occurring at a faster pace than normal. Seen during
exercise

19. SINUS TACHYCARDIA

20. ECG RULES
If you follow Professor Chamberlains 10 rules they'll
give you an understanding of what is normal:-

21. RULE 1
PR interval should be 120 to 200
milliseconds or 3 to 5 little squares

22. RULE 2
The width of the QRS complex should not
exceed 110 ms, less than 3 little squares

23. RULE 3
The QRS complex should be dominantly upright in
leads I and II

24. RULE 4
QRS andT waves tend to have the same general
direction in the limb leads

25. RULE 5
All waves are negative in lead
aVR

26. RULE 6
The R wave must grow fromV1 to at leastV4
The S wave must grow fromV1 to at leastV3
and disappear inV6

27. RULE 7
The ST segment should start isoelectric except inV1
andV2 where it may be elevated

28. RULE 8
The P waves should be upright in I, II, andV2 toV6

29. RULE 9
There should be no Q wave or only a small q less than
0.04 seconds in width in I, II,V2 to V6

30. RULE 10
TheT wave must be upright in I, II,V2 toV6

31. REFERENCES:-
The EKG made easy-John R. Hampton
www.ambulancetechnicianstudy.co.uk
www.learntheheart.com