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Health condition

Hypoplastic left heart syndrome, prostaglandin, staged palliation and lifelong single-ventricle care.

A rare, serious congenital heart defect where the left side of the heart cannot support the body, treated in specialist commissioned UK centres through Norwood, Glenn and Fontan surgery.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against NICE, NHS specialist commissioning and peer-reviewed paediatric cardiology sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including staged palliation, hybrid Norwood and the Fontan pathway.

Key facts

HLHS at a glance.

The essentials, in plain English, what HLHS is, how it presents, and how UK specialist commissioned centres treat it.

  • What it is

    A severe congenital heart defect in which the left side of the heart, the mitral valve, left ventricle, aortic valve and ascending aorta, is too underdeveloped to support the body.

  • How rare

    Roughly one in every five thousand births, making it one of the rarer but most serious congenital heart defects seen in the UK.

  • Duct-dependent

    The newborn circulation relies on the patent ductus arteriosus, kept open with a prostaglandin E1 (alprostadil) infusion until surgery.

  • Prenatal diagnosis

    Most cases are picked up on the routine 18 to 22 week fetal cardiac scan and confirmed by a specialist commissioned fetal echocardiogram.

  • Staged palliation

    A three-stage surgical pathway, Norwood then bidirectional Glenn then Fontan, delivered in specialist commissioned paediatric cardiac centres.

  • Lifelong care

    Even after Fontan completion, HLHS is a lifelong condition needing structured follow-up in specialist commissioned adult congenital heart services.

Why this guide matters

A rare condition, a well-organised UK pathway.

HLHS is not common, but its care is highly structured. The three ideas below shape everything else on this page.

  • The duct keeps babies alive

    A prostaglandin infusion holds the ductus arteriosus open until surgery, and is often the difference between survival and collapse.

  • Staged palliation, not a single fix

    Norwood, Glenn and Fontan are three linked operations across the first few years, delivered in specialist commissioned centres.

  • Care is lifelong

    HLHS follow-up runs into adulthood, with structured heart, liver and neurodevelopmental surveillance in specialist teams.

How the diagnosis is made

From the fetal scan to the operating theatre.

The steps a UK fetal medicine, neonatal and paediatric cardiology team will normally follow, in order, so families know what to expect.

  1. 01

    Prenatal

    Fetal anomaly scan

    The 18 to 22 week scan looks at the four cardiac chambers and outflows. An abnormal left heart triggers urgent referral.

  2. 02

    Prenatal

    Specialist commissioned fetal echo

    A detailed fetal echocardiogram in a specialist commissioned fetal cardiology unit confirms HLHS and plans delivery. See our guide to the fetal echocardiogram.

  3. 03

    Prenatal

    Antenatal counselling

    Parents meet a paediatric cardiologist and cardiac surgeon to discuss the staged pathway, transplant and comfort-care options.

  4. 04

    Postnatal

    Delivery in a linked centre

    Birth is planned close to a specialist commissioned neonatal cardiac unit so a prostaglandin infusion can start within minutes.

  5. 05

    Postnatal

    Postnatal echocardiogram

    A neonatal echocardiogram maps the exact anatomy, valve function, atrial septum and ductus, guiding the first operation.

  6. 06

    Planning

    Multidisciplinary planning

    A specialist commissioned MDT of paediatric cardiology, cardiac surgery, neonatology and cardiac ITU agrees the surgical route.

  7. 07

    Planning

    Parent consent and preparation

    A frank conversation about risks, benefits and long-term expectations, with written information and access to family support charities.

Typical timeline: antenatal diagnosis at 18 to 22 weeks, surgery in the first week of life, staged operations across the first few years.

Symptoms

How HLHS shows itself in a newborn.

The classic mix of cyanosis, poor perfusion and acidosis in the first hours or days of life, and the features that mean it is time to escalate.

  • Central cyanosis

    A bluish tinge to the lips, tongue and skin as oxygen levels fall when the ductus starts to close.

  • Circulatory collapse

    Pale, mottled, cool baby with poor feeding and lethargy, a red flag for a duct-dependent lesion.

  • Metabolic acidosis

    Rising lactate on a blood gas as the body struggles to perfuse tissues, needing urgent transfer.

  • Weak or absent pulses

    Weak femoral and brachial pulses reflect very low cardiac output from the failing left heart.

  • Heart murmur

    A non-specific systolic murmur may be heard, though the diagnosis rests on echocardiography rather than auscultation.

  • Tachypnoea and grunting

    Fast, laboured breathing as pulmonary blood flow rises and pulmonary oedema develops.

  • Poor feeding

    Sweating, tiring quickly and taking very small volumes, often the earliest sign parents notice.

  • Red flag - shock as PDA closes

    Sudden deterioration in the first hours to days of life is a paediatric emergency needing a prostaglandin infusion and specialist commissioned transfer.

Treatment

How HLHS is treated in the UK.

Prostaglandin first, then staged surgery in a specialist commissioned centre, with transplant as an option for selected children and structured lifelong follow-up.

  • Prostaglandin E1 (alprostadil)

    An intravenous infusion started at diagnosis to keep the ductus arteriosus open until surgery. It is the single most important early intervention.

  • Neonatal resuscitation

    Careful oxygen and ventilation management to balance pulmonary and systemic flow, delivered by a specialist commissioned neonatal cardiac team.

  • Stage I - Norwood procedure

    Open-heart surgery in the first week of life to reconstruct the aorta and secure pulmonary blood flow, either via a modified shunt or a right ventricle to pulmonary artery conduit.

  • Hybrid Norwood

    An alternative first stage using bilateral pulmonary artery banding and a ductal stent, sometimes preferred for higher-risk newborns.

  • Stage II - bidirectional Glenn

    At around four to six months, the superior vena cava is joined directly to the pulmonary artery, offloading the single ventricle.

  • Stage III - Fontan completion

    Between two and four years, the inferior vena cava is routed to the pulmonary artery so blue blood flows passively to the lungs. See our guide to the Fontan procedure.

  • Heart transplant

    For selected babies or older children with a failing single ventricle, a heart transplant is offered in a specialist commissioned transplant centre. See our heart transplant clinic guide.

  • Lifelong surveillance

    Echocardiography, cardiac MRI, exercise testing and, in later life, liver imaging under specialist commissioned adult congenital heart teams.

What this guide is based on

The sources behind every claim on this page.

UK national commissioning documents and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your fetal medicine team, paediatric cardiologist or adult congenital heart specialist knows your child and their anatomy, and can tell you which parts apply.

  • NHS England. Specialised services for congenital heart disease (paediatric and adult).

  • British Congenital Cardiac Association. Standards for congenital heart disease services.

  • European Society of Cardiology. Guidelines for the management of adult congenital heart disease.

  • Royal College of Paediatrics and Child Health. Guidance on newborn examination and duct-dependent lesions.

Red flags

When HLHS needs urgent attention.

Every HLHS journey has moments that demand specialist input. These are the situations that need urgent contact with the specialist commissioned centre.

  • Shock as the duct closes

    Sudden pallor, weak pulses, cool peripheries and rising lactate in a newborn need an immediate prostaglandin infusion and urgent transfer to a specialist commissioned cardiac centre.

  • Restrictive atrial septum

    A small atrial communication drives severe cyanosis at birth and needs emergency catheter or surgical intervention.

  • Protein-losing enteropathy

    Falling albumin, diarrhoea and oedema after Fontan can signal protein-losing enteropathy, a serious complication needing specialist commissioned review.

  • Plastic bronchitis

    Recurrent cough with rubbery airway casts is a rare but important post-Fontan complication needing multidisciplinary care.

  • Arrhythmia

    New palpitations, syncope or dizziness in older children and adults with HLHS need urgent electrophysiology assessment.

  • Fontan-associated liver disease

    Chronic Fontan physiology can drive liver fibrosis and cirrhosis. Structured hepatology surveillance is now standard.

  • Failing Fontan circulation

    Worsening exercise tolerance, fluid retention or cyanosis may signal a failing single-ventricle circulation and prompts transplant assessment.

  • Neurodevelopmental concerns

    Learning, attention and motor difficulties are more common after neonatal cardiac surgery and need proactive specialist commissioned follow-up.

  • Endocarditis risk

    Any unexplained persistent fever needs blood cultures and specialist advice, given the lifelong risk of infective endocarditis.

Living with it

A lifelong condition, a lifelong team.

Four things that make the biggest difference year on year, a strong link to the specialist centre, steady surveillance, everyday support and the wider HLHS community.

A quiet reminder

You are not walking this path alone.

Specialist commissioned cardiac teams, charities such as Little Hearts Matter and the Somerville Foundation, and other HLHS families are all part of the network around your child.

  1. 01 Team

    Stay linked to your specialist commissioned centre

    Great Ormond Street, Birmingham Children’s, Alder Hey, Bristol and Newcastle all run specialist commissioned paediatric cardiac services, with lifelong handover into adult congenital heart clinics.

  2. 02 Routine

    Never skip surveillance

    Echocardiography, cardiac MRI, exercise testing and liver imaging catch problems while they are still treatable, long before symptoms appear.

  3. 03 Everyday

    Feeding, growth and school

    Nutrition, gentle activity and steady school attendance matter as much as the operations. Community paediatric teams work alongside the cardiac centre.

  4. 04 Support

    Lean on the charities

    Little Hearts Matter and the Somerville Foundation provide peer support, transition guidance and a lifeline for families navigating single-ventricle life.

Frequently asked

Everything we get asked about HLHS.

Quick answers on diagnosis, prostaglandin, staged surgery, transplant and long-term outlook.

  • What is hypoplastic left heart syndrome?

    Hypoplastic left heart syndrome, HLHS, is a severe congenital heart defect in which the mitral valve, left ventricle, aortic valve and ascending aorta are all too underdeveloped for the left side of the heart to pump blood around the body. Without treatment it is not survivable, but with staged surgery children can grow up with a single-ventricle circulation.

  • How is HLHS usually diagnosed?

    Most babies with HLHS are picked up before birth on the routine 18 to 22 week anomaly scan, and confirmed by a specialist commissioned fetal echocardiogram. Where the diagnosis is missed antenatally, it usually declares itself in the first hours or days of life with cyanosis, weak pulses and circulatory collapse as the ductus arteriosus closes.

  • What is the staged palliation pathway?

    HLHS is treated with three operations in specialist commissioned paediatric cardiac centres. The Norwood procedure, or hybrid Norwood, is done in the first week of life, the bidirectional Glenn at four to six months, and the Fontan completion between two and four years. Some children go on to need a heart transplant.

  • Why is prostaglandin so important at birth?

    The circulation in HLHS depends on the ductus arteriosus, a fetal blood vessel that normally closes in the first days of life. An intravenous prostaglandin E1 infusion keeps the duct open, buying time for transfer to a specialist commissioned cardiac centre and safe surgery.

  • What is the long-term outlook?

    Modern UK results after staged palliation are much better than they were a generation ago, and many children reach adolescence and adult life. HLHS remains a lifelong condition, however, with real risks of Fontan failure, arrhythmia, protein-losing enteropathy, plastic bronchitis and Fontan-associated liver disease, so structured adult congenital heart care is essential.

  • Where in the UK is HLHS treated?

    Care is delivered in specialist commissioned paediatric cardiac surgical centres, which include Great Ormond Street, Birmingham Children’s, Alder Hey in Liverpool, Bristol and Newcastle, alongside other specialist commissioned services. Adult follow-up is transferred to specialist commissioned adult congenital heart centres.

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