In other words, there is an energy gradient to propel blood into the aorta and pulmonary artery. During this phase, ventricular pressure normally exceeds outflow tract pressure by a few mmHg. No heart sounds are ordinarily noted during ejection. The opening of healthy valves is silent. Atrial pressure initially decreases as the atrial base is pulled downward, expanding the atrial chamber.
Blood continues to flow into the atria.
This causes ventricular active tension to decrease and the rate of ejection and ventricular emptying to fall. Atrial pressures gradually rise due to venous return. As the ventricles continue to relax and intraventricular pressures fall, a point is reached when the total energy of blood within the ventricles is less than the energy of blood in the outflow tracts. Atrial pressures continue to rise due to venous return. When the ventricular pressures fall below atrial pressures, the AV valves open and ventricular filling begins.