The diagram given here is the standard ECG of a normal person, The P - wave represents the:

1. Initiation of the ventricular contraction

2. Beginning of the systole

3. End of systole

4. Contraction of both the atria

Given below is the ECG of a normal human. Which one of its components is correctly interpreted below?

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

1. R-repolarisation of ventricles

2. S-start of systole

3. T-end of diastole

4. P-depolarisation of the atria