Explain what the P wave, QRS complex and T wave mean on an ECG?

P wave - atrial systole. This is when both atria of the heart contract, to force blood from the atria to the ventricles. The valves that separates the left atrium and the left ventricle is the bicuspid valve; the valve that separates the right atrium from the right ventricle is the tricuspid valve.QRS complex - ventricular systole. This is when both ventricles of the heart contract, to force blood from the heart to the lungs and the rest of the body. (Atrial diastole is also 'hidden' with the QRS complex).T wave - ventricular diastole. This is when both ventricles of the heart relax.