Heart Valves: Vital Gatekeepers
Learn how they work and common problems associated with heart valves

We often speak of the heart as if it were a single entity - an organ the size of a fist or a muscle weighing about 11 ounces. It is, in fact, a structure of great complexity, with its distinct yet integrated components working together to pump about 2,000 gallons of blood through the body every day. Indeed, a healthy heart is a coordinated masterpiece of efficiency, with chambers, valves, an electrical system, arteries, and veins involved in a cascade of events that sustains life. And it is the heart valves that are the gatekeepers of this activity.

Like a room with a door
The heart has four chambers: the left and right atria and the left and right ventricles. If you can picture each chamber as a room, then the valve is the door of that room. This "door" opens to allow the forward flow of blood, then shuts to keep the blood from seeping backward.

The first valve that the blood passes through after its circuit through the body is the tricuspid valve, located between the right atrium and right ventricle. After this, the pulmonary valve directs the blood flow from the right ventricle toward the lungs, where the blood picks up oxygen. Then the mitral valve regulates the flow of the now oxygen-rich blood from the left atrium to the left ventricle, and the aortic valve directs the forward flow of blood from the left ventricle to the aorta and on to the rest of the body. The familiar "lub- DUPP" sound that we associate with a heartbeat is caused by the closing of the valves: "lub" signals valves closing when the heart contracts and pumps blood, and "DUPP" signals the valves closing when the heart relaxes and fills with blood again.

Detecting a problem
Heart valve abnormalities can either be congenital (present from birth) or develop as we age, and they generally fall into two main categories:

-The valve opening becomes narrow, which is called stenosis. A stenotic valve can't open completely.

-The valve can't close completely, which may allow blood to seep backward. This is appropriately called regurgitation.

Sometimes a person may have symptoms such as shortness of breath or extreme fatigue that need to be investigated, but often there are no obvious symptoms at all. A primary care physician may hear a "murmur" - an unusual whooshing noise in addition to the "lub-DUPP" - through the stethoscope during a routine physical examination. Although most heart murmurs are harmless, they can be an indication that something is wrong. Further examination by a cardiologist and the results of an echocardiogram can reveal the location and extent of a valve problem, if one exists. Echocardiography uses technology that's very similar to ultrasound used for viewing a baby in the uterus. "We get similarly good views of the valves and the heart in general. It's an excellent, noninvasive way to see what and where the problem is." says Joseph Auteri, MD, cardiovascular surgeon and the new director of the Heart Institute of Doylestown Hospital.

Repair or replace? That is the question.
Depending on how severe the problem is, the cardiovascular surgeon will choose from among several treatment approaches - including periodic monitoring, medication, and repair or replacement of the valve. When surgery is indicated, repair is preferred over replacement.

"Repairing the mitral valve, for example, is far better than replacing it," says Dr. Auteri. With repair, the patient can avoid blood thinners and the valve holds up longer. But sometimes the valve is too far gone to repair and it has to be replaced with either a biological [tissue] or mechanical valve. Early detection and treatment can allow someone to act before the valve is too diseased and the heart is weakened.

In spite of the problems that can occasionally befall them, heart valves are incredibly rugged and reliable parts of the human anatomy. In fact, the American Heart Association estimates that the average human heart beats ... and the valves open and close ... more than 2.5 billion times in a 70-year lifetime. Now that's a lot of gatekeeping.

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