Hypoplasia is defined as underdevelopment of a tissue or organ, usually due to a deficiency in the number of cells. Hypoplastic left heart syndrome is the underdevelopment of the left side of the heart, including the left atrium and ventricle, the mitral valve, the aortic valve, and the aorta.
In some cases an associated ASD allows blood returning from the lungs to flow through the opening in the septum from the left to the right atrium. The mixed blood enters the right ventricle and is then pumped into the pulmonary artery. The blood reaches the aorta through a patent ductus arteriosus, which is kept open by intravenous medication. This heart defect is fatal within the first days or months of life without treatment.
Options for treatment include a series of three operations collectively known as the Norwood Procedure or heart transplantation. The goal of the Norwood Procedure is to direct deoxygenated blood directly to the lungs and utilize the functional right heart to pump oxygenated blood to the body.
The first stage, performed in the first week of life, is known as the Stage I Norwood Procedure. The connection between the right ventricle and the branch pulmonary arteries is broken and the main pulmonary artery and the small aorta are connected and augmented to create a new, larger aorta. Next, a small tube (shunt) is placed between the aorta and the right branch pulmonary artery to allow for blood flow to the lungs.
Post-Modified Stage I Norwood Procedure
The modified Stage 1 Norwood Procedure connects the Pulmonary artery to the Right Ventricle using a shunt. The underdeveloped Aorta is reconstructed and enlarged.
The right ventricle is converted into a common systemic (to the body) ventricle. The oxygenated and de-oxygenated blood mix in the right atrium and right ventricle and is then dispersed out to the body, through the reconstructed aorta, and to the lungs through the RV to PA shunt and pulmonary artery.
The purpose of the modified Stage 1 Norwood Procedure is to allow blood to circulate in a controlled manner throughout the body, without obstruction.
The Hemi-Fontan procedure is the second of three operations for children with hypoplastic left heart syndrome and other types of single ventricle physiology. This procedure is generally performed at 6 months of age. The Hemi-Fontan consists of anastomosis of the superior vena cava (SVC) to the right pulmonary artery, augmentation of the branch pulmonary arteries and patch closure of the communication between the superior vena cava and the right atrium.
After the Hemi-Fontan procedure, the blue blood returning from the upper body through the SVC is immediately diverted to the lungs, without passing through the heart. This blood becomes oxygenated in the lungs and returns to the left atrium. This red or oxygenated blood then passes through the atrial communication into the right atrium. The deoxygenated blood from the lower body enters the right atrium through the inferior vena cava (IVC); there it mixes with the oxygenated blood from lungs. The mixed blood then passes into the right ventricle and is pumped out into the reconstructed aorta to supply the body. The importance of this procedure is that it relieves the single ventricle of having to pump an excess volume of blood. Prior to this procedure, the ventricle is pumping both to the body and to the lungs. Following the Hemi-Fontan, the ventricle pumps only to the body, since the lung is supplied with blood flow directly from the superior vena cava.
The third and final stage is performed at approximately 12 months of age. During this procedure, the deoxygenated blood of the lower half of the heart is directed to the lungs. This is done by channeling the blood of the inferior vena cava through the right atrium to the right branch pulmonary artery.
What Is Normal Cardiac Anatomy?
When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.
Heart With Normal Cardiac Anatomy
When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.
The heart is composed of four chambers. The two upper chambers, known as atria, collect blood as it flows back to the heart. The two lower chambers, known as ventricles, pump blood with each heartbeat to the two main arteries (the pulmonary artery and the aorta). The septum is the wall that divides the heart into right and left sides. The atrial septum separates the right and left atria; likewise, the ventricular septum separates the two ventricles.
There are four valves that control the flow of blood through the heart. These flap-like structures allow blood to flow in only one direction. The tricuspid and mitral valves, also known as the atrioventricular valves, separate the upper and lower chambers of the heart. The aortic and pulmonary valves, also known as the arterial valves, separate the ventricles from the main arteries. Oxygen-depleted blood returns from the body and drains into the right atrium via the superior and inferior vena cavas. The blood in the right atrium then passes through the tricuspid valve and enters the right ventricle.
Next, the blood passes through the pulmonary valve, enters the pulmonary artery, and travels to the lungs where it is replenished with oxygen. The oxygen-rich blood returns to the heart via the pulmonary veins, draining into the left atrium. The blood in the left atrium passes through the bicuspid, or mitral, valve and enters the left ventricle.
Finally, the oxygen-rich blood flows through the aortic valve into the aorta and out to the rest of the body.
From Nemours' KidsHealth
- Cardiac Catheterization
- ECG (Electrocardiogram)
- A to Z: Hypoplastic Left Heart Syndrome
- If Your Child Has a Heart Defect
- A to Z: Tetralogy of Fallot
- Tetralogy of Fallot
- Patent Ductus Arteriosus (PDA)
- A to Z: Patent Ductus Arteriosus (PDA)
- When Your Child Needs a Heart Transplant
- A to Z: Atrial Flutter
- Atrial Septal Defect
- Congenital Heart Defects Special Needs Factsheet
- Coarctation of the Aorta
- Heart Murmurs and Your Child
- Congenital Heart Defects
- Ventricular Septal Defect
- Heart and Circulatory System
Trusted External Resources
It's normal to be nervous about a procedure that involves your child's heart. But cardiac catheterizations are usually no cause for alarm. These procedures are often successful in kids and teens and carry a very low risk of complications.
Kids are usually released from the hospital the very same day and can resume most regular activities within a week.
About Cardiac Catheterizations
Cardiac catheterizations help doctors perform diagnostic tests on the heart and its blood vessels, and even treat some heart conditions. During the procedure, doctors put a long, thin tube (catheter) into a blood vessel and thread it through blood vessels to the heart. Once the catheter is in place, doctors can use instruments to see into the heart and its chambers (via X-ray) and perform certain procedures.
Often, a cardiac catheterization can make open-heart surgery unnecessary, although for more serious heart problems, it's common for cardiac catheterization to be done in addition to open-heart surgical procedures.
Cardiac catheterization is what is called an invasive procedure, meaning it involves going into the body through the skin. However, it is a minimally invasive procedure and is not considered "open" surgery since it's performed without making any large incisions. Usually the only sign that a person has had the procedure is a small puncture hole where the catheter was inserted, usually in the groin area, but sometimes in the arm or neck.
Diagnostic Tests & Treatments
By performing a cardiac catheterization for diagnostic purposes, a doctor can:
- obtain a sample of heart tissue (biopsy)
- evaluate congenital heart defects (those that are present from birth)
- measure the blood pressure inside the heart
- measure the amount of oxygen in the heart
- check for problems with heart valves
- locate narrowed or blocked blood vessels
- determine the need for further treatment or surgery
A number of treatments for heart conditions can be performed during a cardiac catheterization. These include:
- closing holes in the heart that are the result of a congenital defect
- repairing leaky or narrow heart valves
- treating an irregular heartbeat (arrhythmia) by destroying the abnormal heart tissue that's causing the heart to beat irregularly
- removing blood clots
- inflating tiny balloons in obstructed blood vessels or heart valves to increase blood flow (angioplasties or valvuloplasties)
- placing wire devices (stents) in narrowed blood vessels to help keep them open
Cardiac catheterizations are generally safe procedures, particularly in comparison with open-heart surgery. Although complications are rare, any procedure that involves the heart and blood vessels does carry risks, such as:
- bruising or bleeding at the site where the catheter is inserted
- an allergic reaction to the medications or contrast material used during the procedure. Contrast material is a special dye put into the blood vessels that helps doctors see the vessels, valves, and chambers of the heart more clearly.
- skin reactions (similar to a sunburn) from exposure to X-rays
- chest pain
- blood clots
- heart attack, stroke, or kidney damage
Your doctor will discuss these risks with you and your child before the procedure is performed.
Preparing for the Procedure
Before the procedure, the doctor will perform a number of diagnostic tests, including an echocardiogram (ECHO), which uses sound waves to create a picture of the heart. The doctor also might do an electrocardiogram (EKG or ECG) to record the electrical activity of the heart. In rare cases, the doctor might call for a cardiac magnetic resonance imaging (MRI) scan or a CAT scan.
Before the procedure, make sure you discuss any allergies your child has with the doctor, particularly if they involve contrast material, iodine, seafood, latex, or rubber products. Also discuss any medications your child takes. The doctor might have your child stop taking medications or adjust the doses for a few days before the procedure. Bring a list of your child's medications and dosages with you to the hospital.
Your child will be instructed not to eat or drink anything for about 8–12 hours before the procedure. Having something in the stomach can increase the risk of complications from anesthesia. After the procedure, your child will be able to eat and drink.
When it's time to go to the hospital, have your child wear comfortable clothes and remove any jewelry, especially necklaces that may interfere with the pictures to be taken of the heart. At check-in, your child's blood pressure and pulse will be recorded. It's important to keep your child relaxed and distracted at this point so that the heart beats at a normal rate.
If there's a possibility that your child may have to stay in the hospital after the procedure, bring toiletries and any other items that can make the stay more comfortable.
The cardiac catheterization will be performed by a pediatric cardiologist in a catheterization lab. The lab has special X-ray and imaging machines not found in normal operating rooms.
A team of doctors and nurses will be on hand to make sure your child is comfortable and the procedure goes smoothly. In the lab, your child will lie on a small table surrounded by heart monitors and other equipment. The room is kept cool to protect this sensitive equipment, so your child may be offered blankets to keep warm.
First, an intravenous (IV) line will be inserted into your child's arm to deliver medications and fluids during the procedure. A sedative will be given to help your child relax and sleep. Small, sticky patches called electrodes will be placed on the chest; these are attached to an electrocardiograph (ECG) monitor, which will monitor the heartbeat during the procedure.
A nurse will clean and possibly shave the area where the catheter will be inserted, and your child will be given an injection of a local anesthetic (a drug that numbs only a small, specific part of the body, like a hand or patch of skin). Once the area is numb, a plastic sheath (a short, hollow tube used to guide the catheter into the blood vessel) will be inserted into the groin or arm, and then the catheter will follow.
The cardiologist will use X-rays to help guide the catheter as it moves up the blood vessels toward your child's heart. When the catheter is in place, a small amount of contrast material will be injected into the blood vessels and heart.
X-rays will be taken of the heart and if your child needs a treatment (like a valve repair or angioplasty), it will be performed at this time.
After the cardiac catheterization is finished, the catheter will be removed and the site where it was inserted will be bandaged. Your child will recover for several hours while the nursing staff monitors his or her progress. If the catheter was inserted into the groin, your child will need to keep the affected leg straight for a few hours after the procedure to minimize the chances of bleeding at the catheterization site.
If you have a long drive home, stop every hour and have your child walk for 5-10 minutes. If you'll be on a plane, have your child stretch his or her legs and walk in the aisle at least once an hour.
The day after the catheterization, your child may remove the bandage. This is easily done by getting it wet in the shower and taking it off. Once the area is dry, replace the bandage with a small adhesive bandage. It's normal for the site to be bruised, red, or slightly swollen for a couple of days after the procedure.
Have your child gently wash the site with soap and water at least once a day, but he or she should avoid baths, hot tubs, and swimming for 1 week after the catheterization. Don't use any creams, lotions, or ointments on the area.
The doctor will tell you when it's safe for your child to resume activities. In general, your child can expect to feel tired and weak the day after the procedure and will need to take it easy for the first couple of days. This means no heavy lifting (more than 10 pounds) and no sports. After about a week, your child probably will get the go-ahead to return to all normal activities./p>
Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: December 06, 2016