Jonathan Chen, MD: Just like each child is different, so is each heart valve. I'm Dr. Jonathan Chen, a surgeon in the Pediatric Heart Valve Center at Children's Hospital of Philadelphia. My team is one of the most experienced in the country in valve repair and replacement. This video will help you understand the most common atrial ventricular, also known as AV, valve repairs that we perform. To better understand atrial ventricular, or AV valve repair, let's first take a look at the anatomy of the heart. This is your heart. It has four chambers and four valves. The heart's upper chambers are called atria. The lower chambers are called ventricles. Blood passes through a valve before entering, or leaving, each chamber of the heart. AV valves are heart valves that separate the atria from the ventricles.

This includes the mitral valve and the tricuspid valve. It also includes complex valves that have developed abnormally in children, such as those with an AV canal defect or a single ventricle defect. Heart valves are made of flaps of tissue called leaflets. These leaflets work like one-way doors, opening to let blood move forward, and closing to keep blood from flowing backward.

The leaflets are attached to a strong tissue called the annulus. The annulus helps maintain the shape of the valve. Thin, string-like strands of tissue, anchor the leaflets to the heart muscle. These strings are called chordae tendineae or cords. Much like the strings on a parachute, these cords keep the leaflets from opening backward.

The mitral valve has two leaflets, the tricuspid valve has three leaflets, and complicated valves, as often exist in children with single ventricle defects, may even have eight or nine leaflets. To work properly, these leaflets must meet when they close. If the valve doesn't completely close, blood leaks back into the heart, and this is called regurgitation. Atrial ventricular valve regurgitation develops when the AV valve leaflets become prolapsed, distorted, or damaged, or when the annulus attached to the leaflets becomes dilated. A prolapsed leaflet bows or flops backward into the atrium. This is because the chordae tendineae attached to the leaflet have become elongated or stretched out. To repair a prolapsed AV valve, a surgeon often shortens or tightens the chordae. The chordae can also be removed and replaced with a shorter artificial chordae. If the leaflets of the heart valve don't meet in the corners, or the commissures, a surgeon will reconstruct the valve, closing the gaps, so the leaflets meet. If a leaflet has been damaged by infection, a surgeon may patch the damage using tissue from the pericardium.

If the annulus or waistband of the valve becomes too big and the leaflets can't touch, a surgeon will place a small ring around the valve to tighten or reinforce the annulus and allow the leaflets to meet. In infants or smaller children, the annulus can usually be tightened with sutures alone. For complicated valves, such as in patients with single ventricle defects, a surgeon will likely need to use more than one of these techniques to repair the valve.

Atrial ventricular valve repair is highly individualized. The Pediatric Heart Valve Center uses advanced imaging to clearly visualize a patient's heart before, and during, surgery and make the best possible surgical plan for your child.