Zoology - Body Fluids and Circulation Question with Solution | TestHub

A normal electrogram (ECG) is composed of a P wave, a QRS wave (complex) and a $\mathrm{T}$ wave. The P-wave represents the electrical excitation or depolarisation of the atria. The QRS complex represents the depolarisation 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 repolarisation of ventricles. The end of the T-wave marks the end of systole.