Aortic insufficiency is the backward flow of blood from the aorta into the left ventricle through the aortic valve during systole due to abnormalities in the aortic valve or the aorta.  In aortic insufficiency (AI), when the pressure in the left ventricle falls below the pressure in the aorta, the aortic valve is not able to completely close. This causes a leaking of blood from the aorta into the left ventricle. This means that some of the blood that was already ejected from the heart is regurgitating back into the heart. The percentage of blood that regurgitates back through the aortic valve due to AI is known as the regurgitant fraction. For instance, if an individual with AI has a stroke volume of 100ml and during ventricular diastole 25ml regurgitates back through the aortic valve, the regurgitant fraction is 25%. This regurgitant flow causes a decrease in the diastolic blood pressure in the aorta, and therefore an increase in the pulse pressure (systolic pressure - diastolic pressure). Thus, physical examination will reveal a bounding pulse, especially in the radial artery.
Aortic regurgitation pathophysiology
Tricuspid regurgitation pathophysiology
Aortic stenosis pathophysiology
Mitral regurgitation pathophysiology
Tricuspid stenosis pathophysiology
Bicuspid aortic stenosis pathophysiology
Mitral valve prolapse causes
Left ventricular aneurysm pathophysiology