Mitral Valve Defects
What are mitral stenosis, mitral regurgitation and mitral valve prolapse?
Mitral stenosis, mitral regurgitation and mitral valve prolapse are all mitral valve diseases caused by defects of the heart's mitral valve.
The heart is a two-sided pump with four chambers. Four valves control the flow of blood through the heart. The mitral valve sits between the left atrium (upper chamber) and the left ventricle (lower chamber) and is the first valve on the left side of the heart.
A normal mitral valve is made up of two thin leaflets. This valve opens to allow blood to flow from the upper chamber to lower chamber on the left side the heart, then closes to keep blood from leaking back into the upper chamber.
Types of mitral valve defects
- Mitral stenosis: The leaflets are fused, are too thick, or there is some other structural defect in the valve leaflets. Sometimes, mitral stenosis occurs as a result of surgery to repair an abnormal mitral valve. As a result, the valve is too narrow, and the heart has to work harder to pump blood through the valve.
- Mitral regurgitation: The valve doesn’t close completely and allows blood to leak back (regurgitate) into the atrium (upper chamber) from the ventricle (lower chamber). This is also referred to as mitral valve insufficiency.
- Mitral valve prolapse (MVP): When the valve is closed, the leaflets bulge abnormally up, into the atrium. Sometimes mitral valve prolapse causes mitral valve regurgitation. If the prolapse is severe, the valve leaflets can become disconnected from tendons that stretch between the leaflets and the heart muscle. This can cause the valve to malfunction.
Causes of mitral valve defects
Sometimes a baby is born with a defective mitral valve. In other cases, certain heart or health problems can lead to a weakened mitral valve during childhood or adulthood. Rheumatic fever, an acquired disease, can also cause scarring in the heart tissue resulting in mitral stenosis or regurgitation.
Symptoms and signs of mitral valve defects
Symptoms vary widely depending on the type and severity of the condition.
A newborn with severe or critical mitral stenosis may require treatment immediately. Symptoms may include:
- Blue or purple tint to lips, skin and nails (cyanosis)
- Difficulty breathing
In less severe cases, symptoms may include:
- Palpitations or irregular heartbeat (arrhythmia)
- Difficulty breathing during exercise
- Recurrent cough and lung infections
Mitral valve regurgitation can also cause these symptoms. Sometimes symptoms don’t appear until the child is older or an adult.
When mitral stenosis or mitral regurgitation is caused by rheumatic fever, symptoms may not appear until many years after the child has the disease.
Mitral valve prolapse often has no symptoms. In some cases mitral valve prolapse causes arrhythmias (abnormal heart rhythm).
Testing and diagnosis of mitral valve defects
Your pediatrician may hear a heart murmur (an extra heart sound) and refer your child to the Cardiac Center.
Echocardiography (sound waves create an image of the heart) will then be used to make a diagnosis. Diagnosis may also include:
- Chest X-ray
- Electrocardiogram (ECG): a record of the electrical activity of the heart
- Cardiac catheterization: a thin tube is inserted into the heart through a vein and/or artery in either the leg, the neck or through the umbilicus (“belly button” — used in newborns only).
- Cardiac MRI
Treatment for mitral valve defects
Treatments vary widely depending on the type and severity of your child's condition. In many cases, no treatment is necessary. In other cases, your child may need to take medications.
In severe cases, treatment options include:
Balloon mitral valvuloplasty
During this cardiac catheterization procedure, an interventional cardiologist will insert a thin tube (catheter) into a vein in the leg, then guide the tube to your child’s heart. A special technique is then used to guide the catheter across the atrial septum (the thin wall separating the two upper chambers of the heart) and into the left atrium, which allows direct access to the mitral valve. The catheter is then advanced across the mitral valve. The catheter will have a balloon on the end of it. The balloon will be briefly inflated to open up the narrow valve, then deflated and withdrawn. Sometimes, two catheters and balloons are used. After this procedure, older children will spend one night in CHOP’s dedicated post-catheterization recovery unit before returning home. They will also need to rest for the next few days, but then can resume normal activity. Newborns with critical conditions or children who are already inpatients at CHOP may stay in the hospital slightly longer, either in the Evelyn and Daniel M. Tabas Cardiac Intensive Care Unit (CICU), where they will receive around-the-clock attention from a team of dedicated cardiac critical care medicine specialists, or in the Cardiac Care Unit (CCU).
Surgery to repair or replace the valve
Surgeons will separate the valve’s fused leaflets or attempt to repair the valve’s defect so that it can work properly. If the valve cannot be repaired, they will replace it with a mechanical (man-made) valve or a valve from a donated organ. In cases where a mechanical valve is used, your child will need to take a blood thinner for the rest of their life to prevent clots from forming on the valve.
Outlook for mitral valve defects
Because of enormous strides in medicine and technology, today most children with heart conditions such as these go on to lead productive lives as adults.
If your child was born with mitral stenosis, they will require follow-up care. They will need to visit a pediatric cardiologist for evaluation and testing to ensure there is no worsening of the obstruction at the valve. Children who have had a mechanical valve surgically placed will also need routine monitoring to make sure their blood thinner is creating the right amount of thinning effect.
Depending on the severity of the condition and symptoms, children with mitral regurgitation or mitral valve prolapse may or may not require follow-up visits with a pediatric cardiologist. We will discuss follow-up care with you based on your child’s unique needs.
For children who will require ongoing care from a cardiologist throughout their lives, CHOP will help transition care from a pediatric cardiologist to an adult congenital heart disease specialist.
The Philadelphia Adult Congenital Heart Center, a joint program of CHOP and the University of Pennsylvania, meets the unique needs of adults who were born with heart defects.
Reviewed by Chitra Ravishankar, MD