Diastole is the part of the
cardiac cycle when the heart refills with blood following
systole (contraction).
Ventricular diastole is the period during which the ventricles are filling and relaxing, while
atrial diastole is the period during which the atria are relaxing. The term
diastole originates from the Greek word
διαστολη, meaning dilation. Diastole is closely related to the phenomenon of
recoil within
ballistics.