If you have mild aortic valve regurgitation, you will probably not even notice it. However, over a period of several years, the condition tends to get worse. As it gets worse, it can cause other diseases (complications) to develop. The most common complications are heart failure, irregular heartbeats (arrhythmias), and infection in the heart (endocarditis). A major focus of treatment for aortic valve regurgitation will be preventing these complications.

Heart failure

Heart failure is one of the most common complications of aortic valve regurgitation. It involves a loss of heart function that progressively worsens and can lead to death. If you have chronic regurgitation, your heart is able for a while to compensate for the extra blood leaking back into the left ventricle and prevent it from affecting your other organs. However, over a long period of time—from several months to several decades—your heart will weaken.

Heart failure caused by regurgitation occurs when the heart becomes so weakened that it can no longer deliver all of the blood the body needs. The heart serves as a pump in the body, moving all of the blood through the circulatory system. When the pump begins to fail, blood is not moved through the body properly, depriving organs of the oxygen and nutrients they need to function correctly. Because it causes damage to the left ventricle, aortic valve regurgitation causes left-sided heart failure.

If you develop heart failure from aortic valve regurgitation, you will likely experience shortness of breath, the most common symptom of left-sided heart failure. You may have difficulty catching your breath because, as your heart begins to fail, blood begins to back up in your lungs. Fluid in the lungs reduces the space available for oxygen exchange to take place, causing you to feel as though you cannot get enough air into your lungs.

Irregular heartbeats (arrhythmias)

The heart is a muscle that contracts to pump blood out and relaxes to allow blood back in. A network of nerves covers the surface of the heart. When these nerves fire (send an electrical signal), they cause your heart to contract. A collection of cells on the right atrium, called the sinoatrial node, controls this web of nerves. As it fires, so do the rest of the nerves, causing all of the muscle cells in the heart to contract together, producing one forceful pump. The electrical activity of the heart starts in the atrium and travels through another collection of cells called the atrioventricular (AV) node to reach the ventricles.

As aortic valve regurgitation stretches the heart muscle, it can also disrupt this web of nerves. Communication pathways may weaken and not deliver the signal from the sinoatrial node effectively. Because the AV node is close to the aortic valve, the stretching and scarring caused by aortic valve regurgitation can damage the AV node.

• Damage to the AV node may cause a slowed heartbeat (bradyarrhythmia) or a more serious condition called heart block. Heart block refers to an abnormality in the conduction of electricity through the normal electrical pathways of the heart. The abnormality "blocks" the electrical impulse from continuing through the normal electrical pathways and usually results in a slower heart rate. If you have bradyarrhythmia or heart block, you may feel faint, dizzy, lightheaded, and short of breath and have chest pain, fatigue, and palpitations; you may also be confused or have difficulty concentrating and increased difficulty exercising. A slow heart rate can sometimes be treated with medications, but in many cases a pacemaker is surgically implanted to help the heart beat at a normal rate. Treatment of heart block usually requires a pacemaker.
• Stretching and enlargement of the atria (the heart's upper chambers) may also result in an irregular heartbeat, such atrial fibrillation. Symptoms of atrial fibrillation may include weakness, shortness of breath, and heart palpitations or more serious problems such as fainting (syncope).

The irregular beats prevent the blood from flowing smoothly through the heart; this allows clots to form. If these clots break loose, they can travel to your brain and cause a stroke.

Infection in the heart

If your heart has already been weakened by valve problems, infection can further worsen its function. Bacteria also may be able to eat a hole through the valve, further worsening the regurgitation. If the bacteria clump in the bloodstream, they can cause problems with circulation, and even cause strokes. An infection in your heart can be a life-threatening matter that needs immediate treatment.

Infections in the heart (endocarditis) can cause and be caused by aortic valve regurgitation. Endocarditis is considered a complication of regurgitation when regurgitation causes it. An infection in the heart is caused by bacteria that have set up residence in the heart or on a valve by attaching to the wall of the heart or valve. The small imperfections in valves create a convenient nest for the bacteria to settle, which is why a valve problem places you at increased risk for infection.

Your heart and blood vessels are structured so that bacteria have a difficult time attaching and creating an infection. The surfaces of the insides of the heart and blood vessels are smooth and uniform, giving bacteria little chance to gain a foothold on which to grow. However, when the structure of your valve is altered, the smooth lining is also altered.

Once bacteria begin to grow and reproduce, they have access to all the food they need from the sugar (glucose) in your blood. The bacteria will likely grow rapidly, often so fast that your body's immune system cannot keep the infection in check.

Bacteria clump together, becoming a larger mass attached to the heart muscle or valve. These clumps are called vegetations, and as they become larger, pieces are likely to break off. The pieces act much like a blood clot. They can block your arteries, causing heart attacks and stroke. They also can spread the infection throughout your body by traveling through your bloodstream.