Ventricular Filling : Systole or Diastole?
Ventricular diastole is a period in cardiac cycle during which the ventricles are filling with blood. During this period, the atria are contracting and the ventricles are relaxed.

The diastole consist of this: atrioventricular valves open, atria contract (atrial systole), blood flows from the atria to the ventricles, the atrioventricular valves close.

When the term systole or diastole is used without saying is it atrial or ventricular, it means it is ventricular. For example, systolic blood pressure is the blood pressure during ventricular systole and diastolic during ventricular diastole.