Systole:

The time at which ventricular contraction occurs is called systole. systole is the contraction of the chambers of the heart, driving blood out of the chambers. The chamber most often discussed is the left ventricle. However, all four chambers of the heart undergo systole and diastole in a timed fashion so that blood is propelled forward through the cardiovascular system.

Diastole:

Diastole is the period when the heart fills with blood after systole (contraction). Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are relaxing. The term diastole originates from the Greek word meaning dilation.