The heart is the primary engine that keeps your body running. That hardworking engine has two separate motors, both of which are split into an upper atrium and a lower ventricle that the fuel (your blood) passes through before it's bound for other parts of your body. Each motor also has two valves. Instead of regulating the flow of air, fuel and exhaust as they do in a car, your heart's valves are in charge of blood flow.
Two sets of valves primarily supervise your heart's blood flow. The atrioventricular valves sit between the atrium and ventricle. On the left side of your heart, this specific gateway is called the mitral valve, and on the right, the tricuspid valve. The semilunar valves, however, serve as the exit doors that blood pulses through as it leaves the ventricles on its way to the fuel lines (your arteries). On the left, this semilunar valve is called your aortic valve, and on the right, the pulmonary valve.
We need heart valves because they keep our blood flowing in one direction by opening and allowing it to pass, and then closing to prevent it from flowing backward. Your body is a closed system, meaning blood travels in essentially one big loop, so the closed valves allow pressure to build up before releasing two ventricles' worth of blood from the heart.
But let's get back to our engine analogy for a second. The motor on the right side of the heart has it easy. It receives blood at low pressure as it arrives from all corners of your body and sends it right next door to the lungs, which prefer a steady stream of blood, not a roaring river.
On the left side, however, it's a different story. Blood is entering the left atrium from the nearby lungs at low pressure, but this motor must then push it through the chambers and valves with enough force to shoot the newly oxygenated blood to every tissue in your body. In fact, the left side of our hearts works so hard that we normally identify our heart as being on the left side of our chests when it actually sits in the middle. With that unbalanced workload, it's no wonder that 95 percent of the time the heart valves from the left side are the ones that need replacing [source: St. Jude].
One of these valves, the aortic valve, guards the passageway between the left ventricle and the aorta, your primary supply artery for oxygen-rich blood. If this part malfunctions, as it does in aortic valve disease, your engine is in for a hard day's driving.
Causes and Effects of Aortic Valve Disease
Your aortic valve normally has three snugly fitting, triangular leaflets (sometimes called cusps or flaps) attached to a ring of tissue called the annulus. Aortic valve disease occurs when stenosis, regurgitation or, in really unlucky people, both cause the aortic valve not to work properly.
Stenosis happens when you have a narrowed or hardened valve that restricts the amount of blood passing through it. Regurgitation occurs when blood leaks back into the ventricle through poorly sealing leaflets. In either scenario, your heart must pump harder to push the proper amount of blood through the faulty passage. As a result of the extra effort, either the heart tissue gets thicker (hypertrophic cardiomyopathy) or the left ventricle becomes larger (dilated cardiomyopathy), ultimately reducing your heart's performance. Your aortic valve isn't the only one that can be diagnosed with stenosis or regurgitation, but it's the one that matters in aortic valve disease.
What causes this aortic sentry to go awry? Calcium, for one. As we get older, it accumulates on the aortic valve, and this is a primary cause of stenosis [source: Nishimura]. These deposits stiffen the leaflets, thicken the annulus and commonly appear around age 60, but they don't necessarily have anything to do with your calcium intake [source: Mayo]. An aortic valve that started off too narrow from birth also can lead to stenosis (called congenital aortic valve disease). Regurgitation, on the other hand, may stem from good old-fashioned wear and tear, problems with the aorta itself and rheumatic fever (also a cause of stenosis).
If your aortic valve is damaged, your body may alert you in a variety of ways. You may feel dizzy, suffer chest pains or see swelling in your feet. Early on, you may notice you're especially winded during exercise. As the condition progresses, shortness of breath can occur when you're resting or even sleeping. A heart murmur may also develop, and this telltale sign often alerts doctors to the condition during routine checkups.
Without serious symptoms, aortic valve disease may simply require an easygoing lifestyle -- due to the heart's limited ability to deliver oxygenated blood -- and regular cardiology exams. Sometimes, doctors can open a stenotic valve by inserting a catheter with a tiny balloon into the body, pushing it through a vein to the aortic valve and then expanding the balloon, knocking the leaflets fully apart. Other times, surgeons reshape leaflets to prevent regurgitation. However, if symptoms worsen, your faulty aortic valve may need to be replaced with a mechanical or biological one during open-heart surgery [source: Nishimura].
After a successful transplant, patients are usually as good as they ever were, or even better [source: Sundt]. If you have aortic valve disease and need a transplant, console yourself in knowing that, after the procedure, you'll likely be living a long, happy life as you motor on down the road with a top-notch replacement valve in your tuned-up engine.
See the next page for many more stories about that hardworking engine of yours.
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