In left ventricular systole, which chambers of the heart are contracting and which are filling with blood?

Ventricles contracting, atria filling with blood.

During this phase, the ventricles are contracting - the right ventricle pumps deoxygenated blood into the pulmonary arteries towards the lungs for oxygenation, and the left ventricle pumps oxygenated blood under high pressure into the aorta to be sent to all parts of the body.

Both atria are relaxed and filling with blood - the right atrium is filling with deoxygenated blood from the superior and inferior venae cava as well as the subclavean veins, whereas the left atrium is filling with oxygenated blood from the pulmonary veins from the lungs.

The average systolic blood pressure during this phase of the heart beat is between 100 - 120 mmHg for a healthy adult person.