Hypoplastic Right Heart Syndrome: Symptoms, Causes, and Surgical Treatment
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
Hypoplastic right heart syndrome is a rare congenital defect in which the tricuspid valve, pulmonary valve, right ventricle or pulmonary artery does not develop fully. It causes low blood oxygen, with risk of right-sided heart failure. Early signs include cyanosis, rapid breathing and poor feeding. Treatment includes prostaglandin, catheter procedures and staged surgery such as the Glenn and Fontan procedures. [1] [2]
What the research says
Genetics appears to play a role. In a study of 42 babies born with HRHS in California, researchers found candidate copy number variants (gains or losses of DNA segments) in 14 cases (33%). Duplications overlapping part of ERBB4, a gene with a pivotal role in heart muscle cell development, appeared in two unrelated cases. (Giannakou et al., Am J Med Genet A, 2018)
Learning and development may need extra support. A focused review of people with single-ventricle circulation, the kind of circulation created when the right ventricle cannot be used, found moderate to severe neurodevelopmental impairments in one-quarter to one-third of patients. Innate patient factors, rather than factors during surgery, appeared to drive these outcomes, and studies in adulthood are limited. (du Plessis & d'Udekem, Ann Thorac Surg, 2019)
A Fontan circulation calls for lifelong follow-up. A meta-analysis of 61 studies of people with an extracardiac Fontan followed for at least 3 years found pooled rates per 100 person-years of 1.8 for arrhythmia, 1.9 for reoperation, 0.7 for protein-losing enteropathy and 0.3 for late death. The authors note that Fontan palliation improves survival but carries a large burden of lifelong morbidity. (Talla et al., Can J Cardiol, 2025)
What is hypoplastic right heart syndrome?
Hypoplastic right heart syndrome, commonly abbreviated HRHS, is a rare condition present at birth. The right side of the heart normally pumps oxygen-poor blood to the lungs. In babies with HRHS, parts of the right side of the heart do not develop fully, and this causes a low level of oxygen in the blood. [1]
HRHS can affect several parts of the heart, and how well each structure works depends on whether the condition is severe or mild: [1]
Tricuspid valve
Pulmonary valve
Right ventricle
Pulmonary artery
Babies with HRHS may also have another heart problem, such as an atrial septal defect (a hole in the wall between the two upper chambers), a ventricular septal defect (a hole in the wall between the two lower chambers) or an atrioventricular canal defect. [1]
How serious and how common is HRHS?
HRHS is more serious for some people than for others. People with severe problems that cause low oxygen levels need treatment right away, while others have milder problems and are not diagnosed until adulthood. Researchers estimate that fewer than 50,000 people in the United States have an HRHS heart, which makes it rarer than hypoplastic left heart syndrome. [1]
Recognizing the symptoms
Symptoms can include: [1]
Blue skin on the hands and feet (cyanosis)
Shortness of breath (dyspnea)
Rapid breathing (tachypnea)
Not feeding well
Fatigue
A newborn with a bluish tint to the skin or breathing difficulty needs immediate medical evaluation.
Causes and potential complications
The cause of HRHS is unknown. Researchers believe genetics could be involved because more than one person in the same family has had HRHS at birth. [1] [2]
Possible complications
HRHS can lead to: [1]
Low oxygen level (hypoxemia)
Right-sided heart failure
Abnormal heart rhythms (arrhythmias)
As young adults, people with mild HRHS can have miscarriages because of low oxygen levels. [1]
How is HRHS diagnosed?
A healthcare provider can diagnose HRHS during fetal development. Ultrasound, which is noninvasive, lets providers see the fetus's heart, and a fetal echocardiogram gives a better look. [1]
After birth, providers use these noninvasive tests to diagnose HRHS: [1]
Test | What it does |
Pulse oximeter | A monitor that measures the oxygen level in the blood. |
Electrocardiogram (EKG) | Records the heart's electrical activity. |
Echocardiogram (echo) | Uses sound waves to show the heart's chambers, valves and blood flow. |
Heart MRI | Uses magnetic resonance imaging to show detailed pictures of the heart. |
Treatment and surgical pathways
Treatment may include medicine, minimally invasive procedures or surgery. The goal is to help blood reach the baby's lungs so more oxygen can get into it. [1]
Medicine
Prostaglandin can help keep a baby's ductus arteriosus open. This blood vessel lets a fetus get oxygen-rich blood from the birth mother, and it usually closes a few days after birth. In HRHS the usual route to the lungs does not work, so keeping the ductus open helps blood reach the lungs. [1]
Minimally invasive procedures
Ductal stent: a provider uses a catheter to place a small metal tube (stent) inside the ductus arteriosus to keep it open for better blood flow to the lungs.
Pulmonary valve perforation: a provider threads a catheter wire to a pulmonary valve that does not open as it should and makes a hole in it so blood can flow to the pulmonary artery. Some providers use ablation for this.
Surgery
Operations can treat severe cases of HRHS: [1]
BTT shunt: a Blalock-Taussig-Thomas shunt uses synthetic fabric to link the subclavian artery to the pulmonary artery and establish blood flow to the lungs.
Glenn and/or Fontan procedure: months or years later, a surgeon may perform a Glenn procedure, a Fontan procedure or both. Each creates a new route for blood to flow around the right ventricle that is not working well, so blood can travel from a major vein to the pulmonary artery and on to the lungs to pick up oxygen.
Complications of treatment
Stents can move out of place.
A BTT shunt can cause blood vessel narrowing or a nerve injury.
A pulmonary valve perforation can cause abnormal heart rhythms or injury to a blood vessel.
Surgery can lead to high blood pressure, pleural effusions, cardiac arrest, kidney or liver disease, or abnormal heart rhythms.
Recovery time varies by procedure. Surgeries have the longest recovery, and a child could be in the hospital for several days or even more than a week. [1]
Outlook and long-term care
Because of a low level of oxygen early in life, people with HRHS may face challenges such as: [1]
Language issues
Memory issues
Higher risks of heart, liver or kidney problems in adulthood
Mood or anxiety disorders
Difficulty with planning or problem-solving
It is rare for people with severe HRHS to survive into adulthood without surgery, while people with mild HRHS may not realize they have it until adulthood. [1] Research on people with single-ventricle circulation shows that neurodevelopmental support may be needed across the lifespan. [3]
Living with HRHS
The care your baby needs depends on the severity of the condition. If your baby needs surgery soon after birth, you will need to monitor them closely at home, and your provider can show you how. A baby who has surgery needs long-term follow-up appointments. If your child has issues with learning or handling emotions, their provider can refer you to specialists who can help. [1]
Questions to ask your child's provider include: does my child need surgery, how soon, how many surgeries will they need and when, and what is the outlook for my child's specific situation? [1]
Frequently Asked Questions
Is HRHS the same as HLHS?
No. Hypoplastic right heart syndrome affects the right side of the heart, while hypoplastic left heart syndrome (HLHS) affects the left side. HRHS is rarer than HLHS.
What is cyanosis?
Cyanosis is a bluish tint to the skin, often seen on the hands and feet, caused by a low level of oxygen in the blood. It is one of the most visible signs of HRHS in newborns.
Can HRHS be diagnosed during pregnancy?
Yes. A healthcare provider can diagnose HRHS before birth using ultrasound to see the fetus's heart, and a fetal echocardiogram gives a more detailed look.
Is HRHS hereditary?
The cause is unknown, but researchers believe genetics could be involved because more than one person in the same family has had HRHS. In one study of 42 HRHS cases, candidate DNA copy number variants were found in 14 (33%).
What is prostaglandin?
Prostaglandin is a medicine that helps keep a baby's ductus arteriosus open. This fetal blood vessel normally closes a few days after birth, and keeping it open gives blood another route to the lungs.
What is a BTT shunt?
A Blalock-Taussig-Thomas (BTT) shunt uses synthetic fabric to connect the subclavian artery to the pulmonary artery, which establishes blood flow to the lungs in a baby with HRHS.
What is the Glenn procedure?
The Glenn procedure connects the superior vena cava, the large vein carrying blood from the upper body, to the pulmonary artery, so blood flows to the lungs around the right ventricle that is not working well.
What is the Fontan procedure?
The Fontan procedure creates a route for blood returning from the body to flow to the pulmonary artery and then to the lungs, bypassing the underdeveloped right ventricle. It is often done after a Glenn procedure.
How long is the hospital stay after surgery?
Recovery varies by procedure, and surgeries have the longest recovery. A child could be in the hospital for several days, and sometimes more than a week.
What are the risks of treatment?
The risks of treatment vary by procedure. Stents can move out of place, a BTT shunt can cause blood vessel narrowing or nerve injury, and surgery can lead to high blood pressure, pleural effusions, abnormal heart rhythms, or kidney or liver problems.
Can people with mild HRHS live into adulthood?
Yes. Some people have milder issues and are not diagnosed until adulthood. Young adults with mild HRHS can have miscarriages because of low oxygen levels.
Does HRHS affect learning and mood?
Because of low oxygen early in life, people with HRHS may face challenges with language, memory, planning or problem-solving, and have higher rates of mood or anxiety disorders. Providers can refer you to specialists who can help.
How often will my child need follow-up?
A baby who has surgery will need long-term follow-up appointments. The care team will explain what to watch for and what to do if you have concerns.
What questions should I ask my child's doctor?
Ask whether your child needs surgery, how soon, how many surgeries are needed and when, and what the outlook is for your child's specific situation.
References
Cleveland Clinic. Hypoplastic Right Heart Syndrome. Cleveland Clinic. Last updated March 15, 2024. https://my.clevelandclinic.org/health/diseases/hypoplastic-right-heart-syndrome
Giannakou A, et al. Copy number variants in hypoplastic right heart syndrome. Am J Med Genet A. 2018;176(12):2760-2767. PMID 30289599. https://doi.org/10.1002/ajmg.a.40527
du Plessis K, et al. The Neurodevelopmental Outcomes of Patients With Single Ventricles Across the Lifespan. Ann Thorac Surg. 2019;108(5):1565-1572. PMID 31288020. https://doi.org/10.1016/j.athoracsur.2019.05.043
Talla M, et al. Long-Term Outcomes of Fontan Patients With an Extracardiac Conduit: A Systematic Review and Meta-Analysis. Can J Cardiol. 2025;41(6):1162-1171. PMID 39952466. https://doi.org/10.1016/j.cjca.2025.02.017
Medical disclaimer
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you are concerned about your baby's health, consult a pediatrician or pediatric cardiologist.
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