What is the period during the cardiac cycle when the ventricles are completely closed and blood volume in them remains constant as the ventricles contract?

The period during the cardiac cycle when the ventricles are completely closed and blood volume remains constant as the ventricles contract is known as isovolumetric contraction. During this phase, the ventricular pressure rises, but both the atrioventricular and semilunar valves are closed, preventing any blood from entering or exiting the ventricles. This phase occurs after the ventricles have filled with blood and just before the ejection of blood into the arteries.