About endocardial cushion defects
What is endocardial cushion defects?
Atrioventricular septal defect (ASVD) is a general term for a group of rare heart defects that are present at birth (congenital). Infants with ASVDs have improperly developed atrial and ventricular septa and adjoining valves.
The normal heart has four chambers. The two upper chambers, known as atria, are separated from each other by a fibrous partition called the atrial septum. The two lower chambers, known as ventricles, are separated from each other by the ventricular septum. Valves (e.g., mitral and tricuspid) connect the atria (left and right) to their respective ventricles. The valves allow for blood to be pumped through the chambers. Blood travels from the right ventricle through the pulmonary artery to the lungs where it receives oxygen. The blood returns to the heart through pulmonary veins and enters the left ventricle. The left ventricle sends the now oxygen-filled blood into the main artery of the body (aorta). The aorta sends the blood throughout the body.
The parts of the heart described above are formed from an embryonic structure called the endocardial cushions. In individuals with ASVD there is some combination of malformation of these parts of the heart. They may include a hole in the atrial septum, a hole in the ventricular septum, and/or abnormalities of the mitral and triscupid valves. ASVD may be classified as one of three forms: an incomplete (or partial) ASVD (atrial septal defect primum); a transitional form (atrial septal defect and small ventricular septal defect); or a more severe or complete form (large atrial and ventricular defects).
The symptoms of ASVD vary greatly and depend on the severity of the malformations (e.g., valve leakage between ventricles and ventricular size). About half the cases of ASVD occur in children with Down syndrome.
What are the symptoms for endocardial cushion defects?
Symptoms of ECD may include:
- Baby tires easily
- Bluish skin color, also known as cyanosis (the lips may also be blue)
- Feeding difficulties
- Failure to gain weight and grow
- Frequent pneumonia or infections
- Pale skin (pallor)
- Rapid breathing
- Rapid heartbeat
- Swollen legs or abdomen (rare in children)
- Trouble breathing, especially during feeding
What are the causes for endocardial cushion defects?
ECD occurs while a baby is still growing in the womb. The endocardial cushions are two thicker areas that develop into the walls (septum) that divide the four chambers of the heart. They also form the mitral and tricuspid valves. These are the valves that separate the atria (top collecting chambers) from the ventricles (bottom pumping chambers).
The lack of separation between the two sides of the heart causes several problems:
- Increased blood flow to the lungs. This results in increased pressure in the lungs. In ECD, blood flows through the abnormal openings from the left to the right side of the heart, then to the lungs. More blood flow into the lungs makes the blood pressure in the lungs rise.
- Heart failure. The extra effort needed to pump makes the heart work harder than normal. The heart muscle may enlarge and weaken. This can cause swelling in the baby, problems in breathing, and difficulty in feeding and growing.
- Cyanosis. As the blood pressure increases in the lungs, blood starts to flow from the right side of the heart to the left. The oxygen-poor blood mixes with the oxygen-rich blood. As a result, blood with less oxygen than usual is pumped out to the body. This causes cyanosis, or bluish skin.
There are two types of ECD:
- Complete ECD. This condition involves an atrial septal defect (ASD) and a ventricular septal defect (VSD). People with a complete ECD have only one large heart valve (common AV valve) instead of two distinct valves (mitral and tricuspid).
- Partial (or incomplete) ECD. In this condition, only an ASD, or an ASD and VSD are present. There are two distinct valves, but one of them (the mitral valve) is often abnormal with an opening ("cleft") in it. This defect can leak blood back through the valve.
ECD is strongly linked to Down syndrome. Several gene changes are also linked to ECD. However, the exact cause of ECD is unknown.
ECD may be associated with other congenital heart defects, such as:
- Double outlet right ventricle
- Single ventricle
- Transposition of the great vessels
- Tetralogy of Fallot
What are the treatments for endocardial cushion defects?
Surgery is needed to close the holes between the heart chambers, and to create distinct tricuspid and mitral valves. The timing of the surgery depends on the child's condition and the severity of the ECD. It can often be done when the baby is 3 to 6 months old. Correcting an ECD may require more than one surgery.
Your child’s doctor may prescribe medicine:
- To treat the symptoms of heart failure
- Before surgery if ECD has made your baby very sick
The medicines will help your child gain weight and strength before surgery. Medicines often used include:
- Diuretics (water pills)
- Drugs that make the heart contract more forcefully, such as digoxin
Surgery for a complete ECD should be done in the baby's first year of life. Otherwise, lung damage that may not be able to be reversed can occur. Babies with Down syndrome tend to develop lung disease earlier. Therefore, early surgery is very important for these babies.
Is there a cure/medications for endocardial cushion defects?
Yes, there is a cure for endocardial cushion defects. However, it is not always the most effective method of treatment.
- Endocardial cushion defects are often discovered in early infancy when the child has a heart murmur or irregular heartbeat. In some cases, doctors may not diagnose a defect until adulthood.
- If you have an endocardial cushion defect, you may need regular checkups with your primary care physician to monitor your heart health and make sure you stay on top of any symptoms that might arise.
- If you experience symptoms such as chest pain, shortness of breath, fatigue, or palpitations (when your heartbeat feels like it's racing), see your doctor right away—don't wait until the next day!
- For many people with endocardial cushion defects, the best treatment available is surgery to repair or replace the affected heart valves. When done correctly, this type of surgery has a low risk for complications and long-term success with few side effects.
- In some cases, medications may be used to treat symptoms of endocardial cushion defects such as arrhythmias or cyanosis (blue tinge to skin).
- These medications may include Beta-blockers (e.g., propranolol), calcium channel blockers (e.g., verapamil), anti-arrhythmic drugs (e.g., sotalol), and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACE-I/ARB).
Abnormal heart rhythm (arrhythmias),Chest pain (angina),Congestive heart failure,Dizziness or fainting,Fatigue (tiredness),Heart murmur (a swishing sound that occurs when blood flows through the heart)
Breathlessness (dyspnoea),Chest pain (angina pectoris),Swelling of the legs or abdomen,Bluish coloration of skin (cyanosis)