ECG: In 1895 first described by Einthoven, known as 'FATHER OF ECG'. It is a non invasive method. recording of electrical impulses generated in the heart. Important Investigated tool, cardiac activity. #PURVISHAH

1. ECG
- PURVI SHAH
(B.P.T)

3. Electrocardiogram
 An ECG is a permanent record of the electrical impulses
generated in the heart by the depolarization & repolarization
(contraction & relaxation) of the myocardium.
 It is a representation of the electrical events of the cardiac
cycle.
 These impulses are transmitted to the surface of the body
where they are detected & picked up by the electrodes &
measured by electrocardiograph.

5. Clinical use of ECG
 To assess the cardiac functions, e.g. rate, rhythm, &
conduction.
 TO diagnose cardiac rhythm disorders, e.g. heart attack
TO diagnose cardiac diseases, e.g. MI
 To evaluate effects of the treatments, e.g. administration of
cardiac drugs.

6. Rate Rhythm Cardiac
disease
Effect of treatments
Normal = 60
100 beats /
min
Irregular Cardiomyopathy Inotropic effect
Tachycardia Fast Myocardial
infarction
Chonotropic effect
Bradycardia Slow Heart attack Rhythmic effect

7. ECG lead placement
 12. Leads ECG Placement
 3. Standard limbs leads
 3. Augmated limbs leads
 6. Precordial leads

8. Standard limb leads
 LEADS I, II, III
 These are the bipolar leads
that register the voltage
between two electrodes

9. Augmated limb leads
 Leads aVR, aVL, aVF
These are the unipolar leads that register
the activity in the heart which is directed
or located below electrode

10. Precordial lead placement
 V1: 4th intercostal space, right sternal border
 V2: 4th intercostal space, left sternal border
 V3: midway between V2 and V4
 V4: 5th intercostal space, left midclavicular line
 V5: level with V4 anterior axillary line
 V6: level with V4 mid axillary line

13. Leads V1 & aVR- Represent right side of the heart
Leads V2, V3, V4- Represent transition between the right & left
side of the heart
Leads V5, V6. I, aVL- Represent left side of the heart
Leads II, III, aVF- Represent the inferior part of the heart

14. Einthoven’s triangle
It is an imaginary formation of the three
leads in a triangle used in ECG
The heart being a centre of a euilateral
triangle, whose apices are at a right arm,
left leg & left arm.
 The triangle, thus formed is called
Einthoven’s triangle

15. Components of ECG

16. Normal ECG

17. Components of ECG
 ECG consist of waves, complexes, segments & intervals
 Waves Complexes Segments Intervals
P, Q, R, S, T, U QRS P-Q, S-T, T-P P-R, Q-T, R-R

19. P wave
Significance – Depolarization of atria
Time period - <0.12 sec
Abnormalities – Abnormal or absence of SA node
abnormality
P-R Interval
Significance – Time for the impulses to reach the ventricales
Time period - <0.20 sec
Abnormalities – prolonged P-R intervals indicates
conduction of block

20. S-T Segment
Significance – Completion of depolarization of ventricales
Time period - <0.20 sec
Abnormalities – Elevation/Depression represent infarction/ischemia of
myocardium
QRS Complex
Significance – Depolarization of ventricales
Time period - <0.12 sec
Abnormalities – prolonged QRS complex –Abnormal conduction – BBB
T wave
Significance – Complete electrical recovery of the ventricles
Time period - <0.20 sec
Abnormalities – Flat-ischemia/Inverted-infarction

21. Abnormalities of the waves
 Absent of the p wave in atrial fibrillation, atrial flutter, ventricular
tachycardia, hyperkalemia
 Abnormal Q wave - MI
 Abnormal R wave – right ventricular hypertrophy
left ventricular hypertrophy
 Abnormal QRS complex – bundle branch block, intraventricular conduction
defect, ventricular arrhythmias
 Abnormal U wave – left ventricular systolic & diastolic overload (inverted)
hypokalemia, cardiovascular drugs (prominent U wave)

22. Abnormalities of the waves
 Abnormal PR segment – sinus tachycardia, acute pericarditis,
atrial infarction (depression)
 Abnormalities of ST segment – CVA, pulmonary
embolism(depression)
 Abnormalities of P-R interval – coronary artery disease, acute
rheumatic fever (Prolonged P-R interval)
 Abnormalities of Q-T interval – hyperkalemia, hypercalcemia
(shortened Q-T interval)/ mitral valve prolapse, electrolyte
deficiency (prolonged Q-T prolonged)

23. The ECG paper
 Horizontally
One small box – 0.04 sec
One large box – 0.20 sec
Vertically
One large box – 5mm (0.5 mv)

25. Calculating the Heart Rate
 Count the number large square between two consecutive ‘R’
waves then divide the result by 300
 Count number of ‘R’ waves in a 6 sec strip then multiply the result
by 10(this method especially good for irregular heart rates)
 With a rate ruler

26. How to read ECG
 Heart Rate (calculating heart rate with following method)
 Heart Rhythm(regular irregular/irregularly irregular
 Cardiac Axis (describe overall direction of electrical spread
within heart, to determine cardiac axis need to look at leads
I,II,III)
 Look P wave present or absent(check duration, direction&
shape, if P wave are absent indicate irregular rhythm suggest
atrial fibrillation
 PR interval (a prolonged or short indicate certain disease)

28.  QRS complex (width, height, morphology)
 ST segment (elevated or depressed indicate MI)
 T wave
 U wave (>0.5 mm deflection)

29. Causes of poor ECG signal
 oily, dirty & scaly skin
 Dirty electrodes
 Improper application
 Loose electrodes
 Broken cable wire

31. Ventricular Tachycardia

32. Atrial Fibrillation

33. Left Ventricular Hypertrophy

34. Thank You