A single ventricle is a congenital heart defect that occurs due to abnormal development of the fetal heart during the first eight weeks of pregnancy. Children born with a single ventricle defect, have only one heart ventricle which is large enough or strong enough to pump effectively. Your heart has four chambers, the upper chambers (atria) receive blood flowing into the heart, and the lower chambers (ventricles) pump blood out of the heart.
The common belief was that most single ventricle hearts will not work well after 30 to 40 years, but due to improvements in surgical techniques and medical care, this age may increase.
Single ventricle defects are rare, affecting only about five out of 100,000 newborns. Also, this is one of the most complex heart problems, which usually requires at least one surgery.
Rarely, a baby with a single ventricle defect will have "just right" flow into the lungs. Meaning that equal amount of blood will flow to the body and lungs. In those cases the baby will not need intervention in the newborn period.
In most cases, the cause of a single ventricle is unknown. There has not been any genetic link identified. The right or left ventricle's underdevelopment may allow oxygen-poor (blue) blood and oxygen-rich (red) blood to mix. Two or three surgeries treat single ventricle defects. Diagnosis will determine the first surgery but the second and third surgeries are usually the same no matter what kind of heart defect a child has.
A single ventricle heart defect is a congenital condition that occurs when one of the two lower chambers of the heart, known as ventricles, is underdeveloped, smaller, or missing a valve. The heart consists of four chambers: two upper chambers called atria and two lower chambers called ventricles. In a healthy heart, the atria receive blood and the ventricles pump blood out of the heart and back into the bloodstream.
In the case of a single ventricle heart defect, the abnormal ventricle doesn’t have the opportunity to practice pumping blood like the other chambers, so it is not able to fully develop. This results in the heart not being able to properly deliver oxygen to the bloodstream. There are several different classifications of single ventricle defects, but they all originate in the womb.
Single ventricle heart defects include conditions such as Hypoplastic Left Heart Syndrome (HLHS), where the left side of the heart is underdeveloped. Other types include Pulmonary Atresia/Intact Ventricular Septum, where the pulmonary valve does not exist, and Tricuspid Atresia, where there is no tricuspid valve in the heart.
A single ventricle defect poses a major problem for babies born with it, as their hearts aren’t able to circulate enough oxygen in their bloodstream to sustain their life. A baby or young child might appear blue, have a higher risk for heart infections like endocarditis, or experience blood clots and abnormal heart rhythms as a result of their one good ventricle working too hard.
The goal of the surgeries is to rebuild the heart and make sure that it:
Pumps blood out to the body
Returns the blood to the lungs (without being pumped by the heart as it would be in a child with two normal ventricles)
Returns the blood to the heart
A newborn with a single ventricle defect can have:
Trouble breathing
Trouble feeding
Blue or grayish color of the skin and nails
Lethargy (very little activity)
Weak pulses in the arms and legs
Few wet diapers
Single ventricle heart defects are complex congenital conditions that often require a series of treatments. The treatment approach for single ventricle heart defects is typically similar across different types of defects. One of the main treatment strategies is a series of open-heart procedures performed over several years, known as "staged reconstruction". This includes three surgeries: The Norwood procedure, the hemi-Fontan or Glenn, and the Fontan procedure.
The Norwood procedure is usually performed soon after birth. This procedure allows the right ventricle to pump blood to both the lungs and the body without the need for the ductus to be kept open.
The hemi-Fontan or Glenn procedure is usually performed between 4 and 8 months of age. This procedure reduces the workload on the heart by allowing blood returning from the body to flow directly to the lungs.
The Fontan procedure is usually performed between 18 months and 3 years of age. This procedure connects the remaining blood vessels carrying blood from the body to the pulmonary arteries, allowing the rest of the blood coming back from the body to go to the lungs.
In addition to these surgeries, many people with single-ventricle defects require daily or multiple medications. This care is best given by a cardiologist who’s very familiar with the anatomical complexities and complications that these patients have. It’s important to note that all these treatments should be performed by a specialist, such as a cardiologist, who specializes in the diagnosis and management of heart-related disorders.
Single ventricle heart defects are serious congenital conditions that affect the structure and function of the heart. The signs and symptoms of single ventricle heart defects can vary depending on the severity and type of heart defect. These can include cyanosis, difficulty breathing, difficulty feeding, and lethargy. Early diagnosis and treatment are crucial to manage these symptoms and improve the child’s quality of life.
In most cases, children with single ventricle heart defects require intensive medical intervention soon after birth. Symptoms can include a blue or purple tint to the lips, skin, and nails, known as cyanosis. This is due to the lack of oxygen in the blood, which is a direct result of the heart’s inability to properly circulate oxygenated blood.
Difficulty breathing is another common symptom. This can be due to the increased workload on the heart, which can cause the heart to enlarge and weaken.
Difficulty feeding is also a common symptom among children with single ventricle heart defects. This can be due to the increased energy expenditure required for feeding, which can be challenging for a child with a heart condition.
Lethargy, or being very sleepy or unresponsive, is another symptom that can be observed in children with single ventricle heart defects. This can be due to the decreased oxygen supply to the brain, which can affect the child’s level of consciousness.
Testing and diagnosis of single ventricle heart defects are crucial for determining the most appropriate treatment plan. These defects are often diagnosed before birth through fetal echocardiography, making it possible to monitor the pregnancy and delivery so that the mother and baby can receive the best possible care.
An echocardiogram, also known as an echo or cardiac ultrasound, is a safe, noninvasive procedure that uses ultrasound waves to create an image of the size, shape, and movement of the heart, valves, and chambers along with how blood flows. This is the primary diagnostic tool for single ventricle heart defects.
An electrocardiogram (ECG or EKG) is another noninvasive procedure that shows the electrical activity of the heart by placing stickers on the child’s chest. This test can help identify any abnormal rhythms or patterns that might indicate a heart defect.
Cardiac catheterization is a minimally invasive procedure for diagnosis and sometimes treatment. It involves inserting a thin tube in a blood vessel in the leg to measure blood flow and pressure in the heart. This test can provide detailed information about the structure and function of the heart.
A chest X-ray is another diagnostic tool that takes pictures of the heart, lungs, and blood vessels to show if the heart is enlarged. This can help identify any structural abnormalities that might be causing symptoms.
In conclusion, the testing and diagnosis of single ventricle heart defects involve a combination of echocardiograms, electrocardiograms, cardiac catheterization, and chest X-rays. These tests provide valuable information about the structure and function of the heart, which is crucial for determining the most appropriate treatment plan.
Equipped hospitals and advanced specialized centers with experienced doctors and specialists are available in all medical treatment areas in Iran. Since the necessary treatments that need to be done in the first 10 days after birth are performed in Iran, it’s an appropriate choice for parents with babies suffering from Single Ventricle Heart Defects. Tehran’s Shahid Rajaii Hospital is the best in treating such cases.
Single ventricle defects are rare disorders affecting one lower chamber of the heart. The affected chamber may be smaller, underdeveloped, or missing a valve. These defects include Hypoplastic Left Heart Syndrome (HLHS), Pulmonary Atresia/Intact Ventricular Septum, and Tricuspid Atresia.
In HLHS, the heart’s left side — including the aorta, aortic valve, left ventricle, and mitral valve — is underdeveloped. This defect is usually fatal within the first days or month of life unless it’s treated. Although this defect isn’t correctable, some babies can be treated with a series of operations, or heart transplantation.
The treatment involves complex operations that need to be adapted for each child. The first stage (Norwood procedure) allows the right ventricle to pump blood to both the lungs and the body without the need for the ductus to be kept open. The second stage (bidirectional Glenn or hemi-Fontan) is usually performed between 4 and 8 months and the third stage (lateral tunnel Fontan or extracardiac Fontan) is usually performed between 18 months and 3 years.
Despite these treatments, patients often experience severe organ damage or neurodevelopmental problems and some may require an organ transplant. Therefore, patients with single ventricle defects need regular checkups by cardiologists with expertise in adult congenital heart disease as well as ongoing care all their life.
The cost of these treatments can vary greatly depending on the specific condition, the complexity of the surgery, the patient’s overall health, and the healthcare system of the country. In Iran the cost of a single ventricle heart defect treatment is around 5000-7000 USD.
