Hypoplastic left heart syndrome

Diagnosis

• Before birth: Hypoplastic left heart syndrome can be detected in a developing fetus through routine ultrasound examinations conducted during the second trimester of pregnancy. Healthcare providers use non-invasive imaging techniques such as ultrasound and fetal echocardiogram to assess the condition of the baby’s heart before birth, without causing any discomfort or pain to the mother or the fetus.
• After birth: If a baby is born with lips that appear grayish-blue or is having difficulty breathing, it may be an indication of a heart defect, such as hypoplastic left heart syndrome. To determine if this is the case, several tests can be performed, including:
  • Physical examination: During the exam, the doctor will look for other signs of a heart problem, such as a heart murmur, which is a sound that can be heard through a stethoscope and is caused by rushing blood flow.
  • Echocardiogram: This diagnostic test uses sound waves to produce moving images of the baby’s heart on a video screen. For babies with hypoplastic left heart syndrome, the echocardiogram will show a small left ventricle and aorta, as well as any issues with heart valves. Additionally, the test can track blood flow and identify other heart conditions, like an atrial septal defect.
  • Chest X-ray: This test can provide a visualization of the size and shape of the baby’s heart and lungs.
  • Electrocardiogram (EKG): This test measures electrical changes during a heartbeat.
  • Pulse oximetry screening: This test can determine the level of oxygen in the baby’s bloodstream.

These tests can help doctors identify and diagnose potential heart problems in newborns and take appropriate action to treat them.

Treatment

Treatment options for hypoplastic left heart syndrome include surgical procedures or a heart transplant, which will be discussed with the child’s healthcare provider. If the condition is identified during pregnancy, it is advisable to give birth at a hospital that has a cardiac surgery center.

Most children with hypoplastic left heart syndrome will need heart medications and other interventions, and may require a series of procedures at a very young age, including:

• Medication: In order to maintain the ductus arteriosus open and working properly, a medicine known as prostaglandin or alprostadil may be prescribe.
• Breathing device: Respiratory management using a ventilator, or a breathing machine may help with babies who have difficulty breathing.
• Intravenous fluids: An infant could potentially be administered fluids via a catheter that has been inserted into a vein.
• Feeding tube: If infants experience difficulties with feeding or become fatigued during the feeding process, they can receive nourishment through a feeding tube. (1)
• Atrial septostomy: The aim of this medical process is to increase the flow of blood from the right atrium to the left atrium by creating or expanding the opening between the upper chambers of the heart. It is performed in cases where the foramen ovale is either too small or has closed. However, newborns who already have an atrial septal defect may not require this procedure. (1)
• Surgeries and other procedures: Children diagnosed with hypoplastic left heart syndrome typically require multiple surgeries aimed at creating distinct pathways for oxygen-rich blood to the body and oxygen-poor blood to the lungs. These surgeries are conducted in three stages.
  • Norwood procedure. The congenital heart defect is usually treated through a surgical procedure performed during the first two weeks of life. There are various ways to perform this surgery.

The surgical team will reconstruct the aorta and connect it to the heart’s lower right chamber. They may insert a shunt to connect the aorta to the pulmonary arteries, or they may create a connection between the right ventricle and the pulmonary arteries. This will enable the right ventricle to pump blood to both the lungs and the body.

Sometimes, a mixed procedure is necessary. This may involve implanting a stent in the ductus arteriosus to keep the opening between the pulmonary artery and the aorta open. Additionally, bands may be placed around the pulmonary arteries to reduce blood flow to the lungs and create an opening between the atria of the heart.

Following the Norwood procedure, the baby’s skin may still appear discolored due to the mixing of oxygen-rich and oxygen-poor blood within the heart. Nonetheless, successful completion of this stage of treatment can enhance the baby’s chances of survival.

• • Bidirectional Glenn procedure. The second surgery is typically performed on infants aged between 3 and 6 months. During this procedure, the initial shunt is removed, and a connection is made between the pulmonary artery and a major vein that carries blood back to the heart, known as the superior vena cava. If the hybrid procedure was previously performed, additional steps will be taken during this operation.

By creating this connection, the right ventricle’s workload is reduced, as it is mainly responsible for pumping blood to the aorta. Moreover, it allows most of the deoxygenated blood from the body to flow directly into the lungs without the need for a pump.

Once this procedure is completed, blood from the upper body is directed to the lungs, enabling blood rich in oxygen to be pumped to the aorta to supply organs and tissues throughout the body.

• • Fontan procedure. A surgery is commonly performed on young children between the ages of 18 months and 4 years old. During the procedure, a path is created to allow oxygen-poor blood to flow from one of the blood vessels that returns blood to the heart, known as the inferior vena cava, directly into the pulmonary arteries. These arteries then transport the blood to the lungs.

The Fontan procedure ensures that the remaining oxygen-poor blood returning from the body is able to flow to the lungs without mixing with oxygen-rich blood in the heart. As a result of this surgery, the skin’s discoloration is eliminated.

• • Heart transplant. A heart transplant is an alternative surgical option that can be considered. However, due to a limited number of available hearts for transplant, this option is not frequently used. For children who receive a heart transplant, they would need to take medication for their entire life to avoid rejection of the donated heart.
• Follow-up care: Following surgery or a transplant, infants with congenital heart diseases require ongoing care from a cardiologist for the rest of their lives. They may need medications to maintain their heart function, and additional treatment or medication might be necessary if complications arise in the future.

Antibiotics may be required before any other surgery, such as dental procedures. These drugs lower the risk of endocarditis (a heart infection). Some children may need to reduce their physical activity as well. Complications can arise over time, necessitating more treatment or other medications. (1, 2)

• Follow-up care for adults: Adults with congenital heart disease require the expertise of a cardiologist trained in this field to provide proper care. With the recent advancements in surgical procedures, children born with hypoplastic left heart syndrome can now reach adulthood. However, the challenges that adults with this condition may face are not yet fully understood. Hence, regular and lifelong follow-up care is necessary for adults to monitor any changes in their condition.

Individuals who are planning to get pregnant should consult their healthcare provider to discuss the risks associated with pregnancy and available birth control options. Having this congenital heart condition increases the likelihood of cardiovascular problems during pregnancy, miscarriage, and giving birth to a baby with congenital heart disease.