Also known as aortic regurgitation, aortic insufficiency is a heart condition in which the aortic valve does not close tightly enough to avoid leakage, allowing some of the blood that has just been pumped out of left ventricle into the aorta to flow back down into the same ventricle from which it was pumped out. So, in aortic insufficiency some of the blood flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. Aortic insufficiency can develop suddenly or over decades. Aortic insufficiency is a defect of the aortic valve, which makes it not to function adequately. This valve disease has a variety of causes, ranging from congenital heart defects to complications of infectious illnesses. Once aortic valve regurgitation becomes severe, a repair or an aortic valve replacement is necessary through a surgery.
Aortic insufficiency causes dilation, or widening, of the heart left ventricle, which continues to get worse over time. As this area of the heart becomes dilated, it is less able to pump blood to the rest of the aorta. The heart tries to make up for the problem by sending out larger amounts of blood with each heart contraction. This leads to a strong and forceful pulse (bounding pulse).
In individuals with a normally functioning aortic valve, the valve is only open when the pressure in the left ventricle is higher than the pressure in the aorta. This allows the blood to be ejected from the left ventricle into the aorta during ventricular systole. The amount of blood that is ejected by the heart is known as the stroke volume. Under normal conditions, 50–70% of the blood in a filled left ventricle is ejected into the aorta to be used by the body (called the 'ejection fraction'). After ventricular systole, the pressure in the left ventricle decreases as it relaxes and begins to fill up with blood from the left atrium. This relaxation of the left ventricle (early ventricular diastole) causes a fall in its pressure. When the pressure in the left ventricle falls below the pressure in the aorta, the aortic valve will close, preventing blood in the aorta from going back into the left ventricle. In aortic insufficiency, 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.