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

The diagram given here is the standard ECG of a normal person. The P-wave represents the
  1. contraction of both the atria
  2. initiation of the ventricular contraction
  3. beginning of the systole
  4. end of systole

Solution

In ECG, P-wave represents the depolarisation of atria, which leads to the contraction of both atria. T-wave represents the return of ventricles from excited to normal state. The QRS complex represents the depolarisation of the ventricles, which initiates ventricular contraction. The contraction starts shortly after $Q$ and marks the beginning of systole.

Asked in: NEET 2013 (All India)

Practice more Body Fluids and Circulation questions on Aicharya