The moment intraventricular pressures exceed the pressure of the aorta and pulmonary artery, the aortic and pulmonic valves open. Blood ejects into the aorta and the pulmonary artery from the respective left and right ventricles. This results in a large decrease in ventricular volume and an increase in aortic pressure. At rest approximately 2/3 of the ventricle is ejected.
No heart sounds should occur during this phase as the opening of the valves upon ejection of the blood is silent. If there is a sound then this may indicate a sign of valve disease or intracardiac shunts.
