What is Ebstein's Anomaly?
The normal heart has four chambers, two upper chambers called atria and two lower chambers called ventricles. The job of each chamber is different, but, in general, the atria receive blood into the heart, and the ventricles pump blood out of the heart. The flow of blood out of each chamber is controlled by a valve, which keeps blood flowing in one direction. The tricuspid valve is on the right side of the heart between the right atrium and right ventricle.
Ebstein's anomaly is a heart defect in which the tricuspid valve is abnormally formed. The tricuspid valve normally has three flaps or leaflets. In Ebstein's anomaly, one or two of the leaflets are stuck to the wall of the heart and don't move normally. Because the tricuspid valve is malformed in Ebstein's anomaly, it often doesn't work properly and may leak. If the valve leaks enough, some of the blood pumped by the right ventricle goes backwards through the tricuspid valve with each heartbeat, making the heart less efficient. This backward flow of blood prevents proper circulation to the lungs and rest of the body.
What will happen during pregnancy?
Ebstein's anomaly is a very rare birth defect. Prenatal diagnosis is usually based on ultrasound examination of the fetal heart.
Once the condition is suspected, a targeted ultrasound will be performed to rule out the presence of associated anomalies particularly of the upper limbs. A specialized ultrasound of the fetal heart, called an echocardiogram will be performed, and an amniocentesis to look for chromosomal anomalies may be recommended.
Sometimes a hole in the heart, called an atrial septal defect (ASD), will also be identified at the time of the ultrasound or echocardiogram. Although prenatal studies may be suggestive that there is an abnormality, the diagnosis will be confirmed after birth.
Your pregnancy will be closely monitored. The Center coordinator will keep you in contact with all of the appropriate physicians and specialists as well as coordinating the care for you and your baby after delivery.
Will a fetal treatment be required?
Currently, there are no fetal treatments for Ebstein's anomaly. You should continue to be closely followed by your obstetrician and a pediatric cardiologist.
What special considerations should be made for delivery?
Type of delivery - Typically, a cesarean delivery is not necessary unless there are other factors determined by your obstetrician. A delivery plan will be carefully developed by your team of physicians at the Center and will be discussed with you and your obstetrician.
Place of delivery - The baby should be delivered at a hospital that is well prepared to handle babies with congenital heart defects. There should be a neonatal intensive care unit with the capability to provide specialized care and pediatric cardiac surgery services.
Timing of delivery - There is usually no reason to intentionally induce early delivery.
What will happen at birth?
Immediately following delivery, doctors will carefully evaluate your baby. In most cases, there is no immediate danger to the infant. Your newborn will be transferred to the neonatal intensive care unit. The baby will be stabilized in an intensive care unit and your pediatric cardiologist will evaluate the baby. Occasionally, the newborn may need help with breathing and blood pressure.
Patients with Ebstein's anomaly can have symptoms ranging from mild to very severe. If the defect is considered mild, immediate surgery may not be required. However, if the tricuspid valve leaks severely, your infant may develop heart failure or the inability to produce enough oxygenated blood (cyanosis). If this occurs, then urgent surgery may be needed.
Several different operations have been used in patients with Ebstein's anomaly. The most common involves a repair of the tricuspid valve to significantly reduce the amount of leaking. If there is an ASD, it is usually closed at the same time. In some cases the tricuspid valve is so severely malformed that it cannot be adequately repaired. In these patients, the tricuspid valve is replaced with an artificial valve.
In some newborns with Ebstein's anomaly, the defect is very severe. In these patients, not only is the tricuspid valve leaky, but the right side of the heart is severely underdeveloped. Without medical and surgical intervention, they cannot get enough blood flow to the lungs. These babies may require an initial surgery to improve blood flow to the lung, known as a Blalock-Taussing shunt (BTs).
This BT shunt is a temporary way of directing more blood flow to the lungs. Thus, instead of trying to make the right ventricle pump better by fixing the tricuspid valve, the strategy becomes to divert the blood around the right ventricle. A child who has to have a BT shunt placed will also require several other surgeries later in life.
In addition, some infants with Ebstein's anomaly will have abnormally fast heart rhythms called supraventricular tachycardia (SVT). In most cases, this problem can be controlled with medication.
In rare instances, the source of the SVT may be removed by a procedure called radiofrequency ablation.
Most babies born with Ebstein's Anomaly can have normal development and have a good quality of life.
The Center team will help care for you and your infant with Ebstein's anomaly. The Center will develop a comprehensive plan with all of the physicians and specialists involved in the care of you and your newborn before, during, and after delivery.
To learn more about Ebstein's anomaly, please visit the Children's Heart Institute at Children's Memorial Hermann Hospital.
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Note: This information regarding your condition is meant to be a helpful, informative introduction. Because every newborn is different, this may not be applicable to all cases, especially if there are additional defects. Your team of experts at the Center will provide you with information specific to your pregnancy.