The 'a' wave occurs during contraction of the right atrium
The 'c' wave occurs during early ventricular contraction due to the tricuspid valve bulging in to the right atrium.
isovolumetric contraction of the right ventricle
ECG: end of QRS complex
The 'x' descent is due to relaxation of the atrium = downward movement of tricuspid valve
ECG: before T wave
The 'v' wave is due to an increase in atrial pressure before opening of the tricuspid valve. It corresponds to atrial filling/isovolumetric relaxation.
The 'y' descent happens during the emptying of the right atrium and rapid filling of the right ventricle
