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Aortic regurgitation (aortic incompetence, or aortic insufficiency) is leakage of blood back through the aortic valve each time the left ventricle relaxes.
Aortic regurgitation usually has no identifiable cause but may result from a bacterial infection of the valve or rheumatic fever.
Aortic regurgitation causes no symptoms unless heart failure develops.
Doctors make the diagnosis because of physical examination findings, and they use echocardiography to confirm the diagnosis and measure its severity.
The damaged heart valve must be replaced or repaired surgically if the leakage is significant.
As the left ventricle relaxes to fill with blood from the left atrium, blood leaks backward from the aorta into the left ventricle because the aortic valve does not seal completely. The backward leakage of blood increases the volume and pressure of blood in the left ventricle. As a result, the amount of work the heart has to do increases. To compensate, the muscular walls of the ventricles thicken (hypertrophy), and the chambers of the ventricles enlarge (dilate). Eventually, despite this compensation, the heart may be unable to meet the body's need for blood, leading to heart failure, with fluid accumulation in the lungs.
Rheumatic fever and syphilis used to be the most common causes of aortic regurgitation in North America, Australasia, and Western Europe, where both disorders are now rare because of the widespread use of antibiotics. In regions where antibiotics are not widely used, aortic regurgitation due to rheumatic fever or syphilis is still common. Aside from these infections, the most common causes of severe aortic regurgitation are
Spontaneous weakening of the valve or the ascending aorta (the large artery leading from the heart)
A birth defect in which the aortic valve has two, instead of three, cusps (bicuspid valve)
Bacterial infection of the valve (infective endocarditis)
A tear in the lining of the aorta (aortic dissection—see page Aortic Dissection
About 1% of babies have a bicuspid aortic valve, but it commonly does not cause problems until adulthood.
Mild aortic regurgitation causes no symptom other than a characteristic heart murmur that can be heard with a stethoscope each time the left ventricle relaxes. People with severe regurgitation may develop symptoms when heart failure results.
Heart failure causes shortness of breath during exertion (see page Heart Failure). Lying flat, especially at night, makes breathing difficult. Sitting up allows backed-up fluid to drain out of the upper part of the lungs, restoring normal breathing. About 5% of people with aortic regurgitation have chest pain due to an inadequate blood supply to the heart muscle (angina), especially at night.
The pulse, sometimes called a collapsing pulse, is momentarily strong, then disappears quickly because the blood leaks backward through the aortic valve, causing blood pressure to decrease sharply.
The diagnosis is based on the results of a physical examination (such as the collapsing pulse and characteristic heart murmur) and confirmed by echocardiography. Chest x-ray and electrocardiography (ECG) usually show signs of an enlarged heart. Coronary angiography is done before surgery because about 20% of people with severe aortic regurgitation also have coronary artery disease.
Unless aortic regurgitation is mild, surgery is ultimately almost always required. Drug treatment is not especially effective in slowing the progression of heart failure and does not eliminate the need for timely valve repair or replacement, but various drugs may be used to control symptoms prior to surgery. The damaged valve should be surgically repaired or replaced with an artificial valve before the left ventricle becomes irreversibly damaged and heart failure becomes too severe. Usually, echocardiography is done periodically to determine how rapidly the left ventricle is enlarging, so that surgery can be scheduled at an appropriate time.
People who have had a valve replacement are given antibiotics before surgical, dental, or medical procedures (see Table: Which Procedures Require Preventive Antibiotics*?) to reduce the risk of infection of the heart valve.
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