Which of the following is an incorrect statement?

The $\mathrm{T}$ wave represents the repolarization (or recovery) of the ventricles. The end of the T-wave marks the end of systole. The $\mathrm{P}$-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria. The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction.