basics of ecg
DESCRIPTION
TRANSCRIPT
PRESENTED BY: Raghwender Singh (D-
754)
THE BASICS OF EKG
INRODUCTIONECG 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
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
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
MODERN ECG INSTRUMENT
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
THE WIRING DIAGRAM OF THE HEART
• SA
• AV node
• Bundle of His
• Bundle branches (left and right)
THE SHAPE OF ECG
• Contraction of atria - P wave
Ventricular depolarization - QRS complex
Ventricular repolarization - T wave
NORMAL ECG
ECG INTERPRETATION
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
ECG RHYTHM
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.
NORMAL SINUS RHYTHM
SINUS BRADYCARDIALooking 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
SINUS BRADYCARDIA
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
SINUS TACHYCARDIA
ECG RULESIf you follow Professor Chamberlains 10
rules they'll give you an understanding of what is normal:-
RULE 1
PR interval should be 120 to 200 milliseconds or 3 to 5 little squares
RULE 2
The width of the QRS complex should not exceed 110 ms, less than 3 little squares
RULE 3
The QRS complex should be dominantly upright in leads I and II
RULE 4
QRS and T waves tend to have the same general direction in the limb leads
RULE 5
All waves are negative in lead aVR
RULE 6
The R wave must grow from V1 to at least V4The S wave must grow from V1 to at least V3 and disappear in V6
RULE 7
The ST segment should start isoelectric except in V1 and V2 where it may be elevated
RULE 8
The P waves should be upright in I, II, and V2 to V6
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
RULE 10
The T wave must be upright in I, II, V2 to V6
REFERENCES:-The EKG made easy-John R. Hamptonwww.ambulancetechnicianstudy.co.ukwww.learntheheart.com