It is the recording of electrical activity of heart. Electrocardiograph is the instrument which is used to record the electrical current generated in the heart. By means of this instrument,, the electrical current generated in the heart is conducted to remote Parts of the body. the heart current can be recorded by connecting any two parts of the body with this instrument. The connections are called as leads.
LEAD 1; right & left arm
LEAD 2:right arm & left leg
LEAD 3:left arm & left leg.