In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart

• S- start ofsystole 

• T- end of diastole

• P- depolarisation of the atria

• R - repolarisation of ventricles

C.

P- depolarisation of the atria

A normal electrogram (ECG) is composed of a P wave, a QRS wave (complex) and a T wave. The P-wave represents the electrical excitation or depolarization of the atria. The QRS complex represents the depolarization of the ventricles which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole. The T-wave represents the repolarization of ventricles. The end of the T-wave marks the end of systole.