Draw a standard ECG and explain the different segments in it.

In the above diagram each peak is given letters for P to T. the first peak 'P' represents the electrical excitation of the atria. This leads to the contraction of both the atria. The next part QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The last 'T' wave represents the return of the ventricles from excited state to normal state.