An electrocardiogram(ECG) is a simple test that can be used to check your heart's rhythm and electrical activity. Sensors attached to the skin are used to detect the electrical signals produced by your heart each time it beats.

1. ELECTROCARDIOGRAM
By M.Lovishal(BME)

2. ECG(Electrocardiograph)
• ECG is defined as “recording of electrical activity of heart
on a graph paper.”
• The machine which is used to record the electrical activity
of heart is ELECTROCARDIOGRAH.

3. ELECTROCARDIOGRAM
• An electrocardiogram records the electrical signals in the heart. It's a common and
painless test used to quickly detect heart problems and monitor the heart's health.
• Electrical signals from the heart characteristically precede the normal mechanical
function and monitoring of these signals has great clinical significance.
• ECG provides valuable information about wide range of cardiac disorders such as the
presence of an inactive part(infarction) or an enlargement (cardiac hypertrophy) of the
heart muscle.

4. Significance of ECG
• ECG gives information about rate and rhythm of the heart.
• The physical orientation of heart.
• It’s a diagnostic tool for various heart conditions like
hypertrophies, Ischemia, Infraction, arrhythmias conduction
problems ans pace maker activity.
• ECG does not provide information about mechanical activity.

5. ECG Leads
• The electrodes placed over different areas of the heart and
pickup the electrical currents resulting from the potential
different them.
• There are 12 ECG leads.
Limb leads
1.Bipolar leads(lead I,II,III)
2.Unipolar leads(AVR,AVL,AVF)
Chest leads(V1,V2,V3,V4,V5V,V6)

6. ECG Waveform

7. Wave forms
P wave: Atrial depolarization
T wave: Ventricular repolarization
QRS complex: Ventricular depolarization

8. Einthoven triangle
Einthoven rule
I+II+III=0
I+(-II)+III=0
I+III=II

9. Einthoven’s triangle
 Einthoven’s Triangle Einthoven’s Triangle is an equilateral
triangle drawn arbitrarily around an area of the heart, apices of which is
represented by the right arm, left arm and left leg.
 Einthoven law states that if the electrical potentials of two leads are
known at any instant, the third can be determine by simply summing the
first two.

10. P wave
P wave shows atrial depolarization
Its duration is 0.1 sec and height is 2.5mv
Presence of P waves in ECG strips shows the sinus
rhythm

11. T wave
• It represent the ventricular repolarization.
• It is repolarizing wave but shows the upward deflection because
the part depolarized in the last is first to be repolarized, that is
base of heart depolarized in the last but is first to be repolarized.
• T wave should not be more than one third of R wave.
• Tall and peaked R wave is present in hyperkalemia.
• T wave inversion represent ischemia of heart.

12. QRS complex
• QRS complex represent the ventricular depolarization.
• Its normal duration is about 0.08 sec and height is about 5 to
20 small sqrs.
• It is a wide complex because it mask the atrial repolarization.
• Q wave is first wave of this complex but often absent.

13. PR interval
• This is from beginning of P wave to the beginning of Q
wave.
• Its normal duration is from 0.12 to 0.2 sec.
• It represent the conduction time of impulse from SA
node to the ventricles and AV delay.

14. QT interval
• Measured from beginning of Q to the end of the T
wave.
• Its duration is about (10 small sprs).
• It indicates total systolic time of ventricles.

15. ST segment
• This segment present between S wave and T wave.
• It represents the plateau phase.
• Its duration is 0.04 sec

16. J point
• The exact point at which all parts of ventricles are
depolarized i.e at the just end of QRS complex and just at the
beginning of ST segment.
• At the point potential of ECG is zero with no current is
flowing through heart.