What is the name of the waves that are related to the contraction of the ventricles of the heart?

The heart has two contraction cycles, one is the systole and the other one is the diasole. Both are fired by one impulse from the Cranial Nerve X. The delay required for the ventricles to contract are a result of the atrrioventricular node that pauses the impule until the ventricles are filled with blood.