Isovolumetric Relaxation:
The Beginning of Diastole

Pressures:

• The backflow of blood against the closed aortic valve is represented by a characteristic notch known as the dicrotic notch or incisura
• The decline in aortic and pulmonary artery pressures is not as abrupt as it is in the ventricles because of potential energy stored in the vessels walls
• The volume of blood that remains in a ventricle is call the end-systolic volume
• The difference between the end diastolic volume and the end systolic volume represents the stroke volume
• Atrial pressures continue to rise due to venous return