Skip to main content

Health condition · Clinically reviewed

Atrial septal defect, types, symptoms, device closure and surgery.

A common congenital heart defect that can stay quiet for decades. Modern imaging and day-case device closure change the trajectory when it is picked up in time.

Jump to treatment
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

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against ESC adult congenital heart disease guidance, NICE and peer-reviewed sources listed at the end.

  • 03

    Current for 2026

    Reflects modern UK practice for percutaneous device closure, surgical repair and pulmonary hypertension care.

Key facts

Atrial septal defect at a glance.

The essentials, in plain English - what an ASD is, the four types, and how it is closed in the UK today.

  • What it is

    A hole in the atrial septum that allows a left-to-right shunt of oxygenated blood, causing right heart volume overload and pulmonary overcirculation.

  • Types

    Ostium secundum (about 75 percent), ostium primum (about 15 percent), sinus venosus (about 10 percent) and rare coronary sinus defects.

  • How it presents

    Often silent for decades - exertional breathlessness, palpitations, atrial fibrillation, right heart failure or paradoxical stroke may bring it to light.

  • Classic sign

    Fixed splitting of the second heart sound with a soft pulmonary systolic murmur - a giveaway on careful auscultation.

  • Assessment

    Transthoracic echo with bubble study first, transoesophageal echo for anatomy, and cardiac MRI for right ventricular volumes and Qp:Qs.

  • Treatment

    Percutaneous device closure for suitable secundum defects, surgical patch closure for primum, sinus venosus and coronary sinus types.

Why this guide matters

Small hole, big long-term consequences if missed.

Atrial septal defect is common, quiet and reversible - if it is found and closed before pulmonary hypertension sets in.

  • The right ventricle pays the price

    Years of extra volume dilate the right heart and stretch the atria, driving arrhythmia and eventually pulmonary hypertension.

  • Type dictates the operation

    Only secundum defects with adequate rims are closed with a device - primum, sinus venosus and coronary sinus defects need surgery.

  • Eisenmenger changes everything

    Once pulmonary pressures rise irreversibly and the shunt reverses, closure is no longer safe and management shifts to advanced PAH therapy.

How the diagnosis is made

From a murmur to a closure plan.

The steps a UK cardiologist normally follows, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and auscultation

    Fatigue, exertional breathlessness, palpitations or a stroke of unclear cause - plus fixed splitting of the second heart sound.

  2. 02

    Assessing

    12-lead ECG

    Right bundle branch block with right axis deviation in ostium secundum, left axis deviation in ostium primum, atrial arrhythmia in older adults.

  3. 03

    Assessing

    Chest X-ray

    Cardiomegaly with prominent pulmonary vasculature reflects right heart volume overload and pulmonary overcirculation.

  4. 04

    Confirming

    Transthoracic echo with bubble study

    First-line imaging - identifies the defect, quantifies right ventricular dilation and demonstrates the shunt with agitated saline.

  5. 05

    Confirming

    Transoesophageal echo

    Gold standard for anatomic delineation, rim assessment and closure planning - especially for sinus venosus and small primum defects.

  6. 06

    Planning

    Cardiac MRI

    Quantifies right ventricular volumes and function, calculates the shunt fraction Qp:Qs and detects anomalous pulmonary venous drainage.

  7. 07

    Planning

    Cardiac catheterisation - selective

    Reserved for measuring pulmonary artery pressure and confirming shunt calculation when pulmonary hypertension is suspected.

Typical timeline: from first echo to closure decision within a few weeks.

Symptoms

What atrial septal defect actually feels like.

A mix of subtle breathlessness, palpitations and classical examination signs - with red-flag features that mean it is time to act.

  • Exertional breathlessness

    The most common symptom in adulthood - the right heart struggles under years of extra volume.

  • Palpitations and atrial fibrillation

    Long-standing atrial stretch predisposes to atrial fibrillation and flutter - see /conditions/atrial-fibrillation/.

  • Fixed splitting of S2

    The hallmark auscultatory sign - the second heart sound splits and does not vary with breathing.

  • Systolic pulmonary flow murmur

    A soft ejection murmur at the left upper sternal edge from increased pulmonary flow, sometimes with a diastolic tricuspid rumble.

  • Right heart failure signs

    Raised jugular venous pressure, hepatomegaly and ankle swelling appear late as right ventricular function declines.

  • Paradoxical embolism

    A clot crossing the defect can cause stroke or transient ischaemic attack - overlaps with /conditions/patent-foramen-ovale/.

  • Silent for decades

    Many adults are diagnosed incidentally on echo done for another reason - absence of symptoms does not exclude significant shunt.

  • Red flag - Eisenmenger physiology

    Severe pulmonary hypertension with shunt reversal and cyanosis - closure is contraindicated at this stage.

Treatment

How atrial septal defect is treated in the UK.

Percutaneous device closure first for suitable secundum defects, surgical patch closure for the rest, and specialist PAH care for Eisenmenger physiology.

  • Watchful waiting

    Small defects without right ventricular dilation, symptoms or paradoxical embolism may simply be followed with periodic echo.

  • Percutaneous device closure

    First-line for suitable secundum defects under 38 mm with adequate rims - Amplatzer, Occlutech or GORE Cardioform devices, usually a day-case.

  • Surgical patch closure

    For primum, sinus venosus, coronary sinus and secundum defects unsuitable for a device - direct suture or pericardial patch, often via minimally invasive or robotic access.

  • Concomitant valve or cleft repair

    Ostium primum defects usually need mitral valve cleft repair at the same operation - sinus venosus repair often reroutes anomalous pulmonary veins.

  • Atrial fibrillation management

    Rate or rhythm control, catheter ablation and stroke-risk anticoagulation - see /conditions/atrial-fibrillation/.

  • Heart failure medication

    Diuretics, beta blockers and neurohormonal blockade for symptomatic right heart failure alongside definitive closure planning.

  • Pulmonary hypertension therapy

    Sildenafil, bosentan, macitentan, selexipag or prostacyclin - prescribed only through a specialist national pulmonary hypertension centre.

  • Heart-lung transplant

    Reserved for Eisenmenger physiology and end-stage pulmonary vascular disease - closure is no longer an option at that point.

What this guide is based on

The sources behind every claim on this page.

UK and European guidance 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 cardiologist knows your anatomy and history and can tell you which parts apply to you. If in doubt, get seen.

  • European Society of Cardiology. 2020 Guidelines for the management of adult congenital heart disease.

  • NICE. Percutaneous closure of atrial septal defect (IPG). Interventional procedures guidance.

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

  • BSAC and AHA. Guidance on antibiotic prophylaxis for infective endocarditis.

Red flags

When ASD needs urgent attention.

Most defects are managed electively. These are the situations that are not - and where specialist input cannot wait.

  • Eisenmenger physiology

    Long-standing shunt causing severe pulmonary hypertension, shunt reversal and cyanosis - closure is contraindicated and specialist PAH care is needed.

  • Paradoxical stroke or TIA

    Any cryptogenic stroke or TIA in a young adult warrants echo with bubble study to look for an atrial shunt.

  • Progressive right heart failure

    Rising jugular venous pressure, ascites and severe fatigue signal decompensation and need urgent cardiology review.

  • New atrial fibrillation

    A frequent trigger for symptoms and a reason to reassess anatomy and consider closure to reduce future arrhythmia burden.

  • Cyanosis or clubbing

    Central cyanosis or finger clubbing suggests shunt reversal - a serious late feature that changes treatment options entirely.

  • Pregnancy planning

    Women with unrepaired ASD need pre-pregnancy counselling at a specialist adult congenital heart disease clinic.

  • Device-related complications

    Rare but include erosion, embolisation, thrombus and new atrial arrhythmia - any new chest pain or syncope after closure needs urgent review.

  • Down syndrome and primum ASD

    Ostium primum defects cluster with Down syndrome - lifelong specialist follow-up is essential.

  • Suspected endocarditis

    Fever with a heart murmur or after recent device closure needs blood cultures and echo without delay.

Living with it

A fixable defect, with life-long follow-up.

Four things that make the biggest difference day to day - regular review, watching for atrial fibrillation, sensible planning around pregnancy and staying active within advice.

A quiet reminder

Closed early, life expectancy is usually normal.

The earlier a significant ASD is closed, the less arrhythmia and right heart change carries forward.

  1. 01 Follow-up

    Life-long cardiology review

    Whether closed or not, ASD needs periodic echo and clinic review - shunts, arrhythmias and pulmonary pressures can change over years.

  2. 02 Rhythm

    Watch for atrial fibrillation

    Palpitations, breathlessness or fatigue may signal new AF - a simple ECG or ambulatory monitor is often all it takes to confirm.

  3. 03 Pregnancy

    Plan ahead

    Women should have pre-pregnancy counselling at an adult congenital heart disease centre - most pregnancies go well with the right team.

  4. 04 Activity

    Stay active within advice

    Most people can exercise normally after closure - severe pulmonary hypertension is the main reason to restrict activity.

Frequently asked

Everything we get asked about ASD.

Quick answers on defect types, when to close, device versus surgery, endocarditis prophylaxis and long-term outlook.

  • What is an atrial septal defect?

    An atrial septal defect is a hole in the wall between the two upper chambers of the heart. It allows oxygenated blood to flow from the left atrium into the right atrium, giving the right side of the heart extra work and increasing blood flow through the lungs over time.

  • What are the different types of ASD?

    The four types are ostium secundum (the most common, about 75 percent, in the middle of the septum), ostium primum (about 15 percent, part of the atrioventricular canal and often with a mitral valve cleft), sinus venosus (about 10 percent, near the superior or inferior vena cava and often with anomalous pulmonary venous drainage) and the rare coronary sinus defect from an unroofed coronary sinus.

  • When does an ASD need to be closed?

    Closure is generally recommended when there is right ventricular dilation, symptoms, a shunt ratio Qp:Qs above 1.5, exercise intolerance or a history of paradoxical embolism. It is contraindicated once severe pulmonary hypertension has developed with Eisenmenger physiology.

  • Is device closure or surgery better?

    For suitable secundum defects with adequate rims and a diameter under about 38 mm, percutaneous device closure is first-line - it is usually a day-case with a high success rate and low complications. Primum, sinus venosus and coronary sinus defects, and secundum defects unsuitable for a device, need surgical patch closure, sometimes minimally invasive or robotic.

  • Do I need antibiotics before dental work after closure?

    Routine antibiotic prophylaxis for endocarditis is not recommended for atrial septal defect under current UK and international guidance. After device closure a short period of prophylaxis (typically six months) is usually advised while endothelialisation completes - your cardiologist will confirm.

  • What is the long-term outlook?

    Closed early, most people have a normal life expectancy and quality of life. Closed late, atrial fibrillation and some right heart changes may persist. If left untreated into middle age, the risks of arrhythmia, right heart failure and pulmonary hypertension rise, and Eisenmenger physiology is a serious late complication.

Related content

Keep reading.

Pulse Healthcare concierge

Send us your enquiry

A concierge service for UK private healthcare. We match you with the best vetted clinics and consultants in our network - they then contact you directly.

So we can match you to the right clinician close to you.

We reply to every enquiry within 24 hours (Mon–Fri). Confidential - your details are never shared outside our vetted consultant network.