The “a” wave in the right ventricle reflects the additional thrust of blood from the atrial contraction.

When the ventricle first starts to contract the tricuspid valve closes and pressure is generated quickly but the ventricular volume does not change thus the name, “isovolumeric”(no change in volume), until enough pressure is generated to open the pulmonary valve.

When the right ventricle generates enough pressure to exceed the pressure on the other side of the pulmonary valve opens and the ventricular volume is ejected into pulmonary artery.

Ventricular relaxation allows interventricular pressures to decrease rapidly.