Congenital heart disease in adults

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Adult congenital heart disease spans simple defects such as small shunts to Fontan circulation, systemic right ventricles, cyanotic disease and complex surgical reconstructions. The same symptom can have very different physiology in each anatomy.

The safest general rule is to stabilise standard life threats while contacting ACHD expertise early. Avoid air in IV lines where right-to-left shunting is possible and avoid abrupt changes in systemic or pulmonary vascular resistance in cyanotic/Fontan physiology.

Exercise testing, ambulatory rhythm monitoring, cross-sectional imaging and catheterisation are selected by lesion and question; serial change is often more important than a single measurement.

Eisenmenger syndrome is advanced pulmonary vascular disease with bidirectional/right-to-left shunting and cyanosis. Management belongs in an expert pulmonary-hypertension/ACHD centre; routine venesection, routine oxygen and indiscriminate anticoagulation can cause harm.

Key points

Never assume childhood repair equals cure: residual shunts, valve disease, ventricular dysfunction, aortopathy, pulmonary hypertension and scar-related arrhythmia may emerge decades later.
Identify the exact anatomy, operations/interventions, ventricular physiology, shunts/conduits, devices, baseline saturation and usual ECG before interpreting acute findings.
Transthoracic echo is first-line; CMR is central for right-ventricular volumes, flows and extracardiac anatomy, while CT helps with coronary arteries, conduits, calcification and stent detail.
Moderate or complex ACHD and clinically significant residual lesions need lifelong specialist follow-up; involve ACHD expertise before invasive procedures, pregnancy or major non-cardiac surgery.
An ASD is closed for significant right-ventricular volume overload when pulmonary vascular resistance permits; device closure is preferred for suitable secundum anatomy.
Do not close a shunt blindly in pulmonary vascular disease. PVR at least 5 Wood units or desaturation/Eisenmenger physiology requires expert catheter assessment and may make closure harmful.
Coarctation clues include upper-limb hypertension, radiofemoral delay and an arm-leg systolic gradient at least 20 mmHg; surveillance continues after repair because recoarctation and aortic complications recur.
In repaired tetralogy of Fallot, falling exercise capacity, arrhythmia, worsening pulmonary regurgitation and progressive RV enlargement can trigger pulmonary-valve replacement assessment.
Routine antibiotic prophylaxis is not recommended by NICE solely because congenital heart disease is present. Maintain excellent oral health and investigate infection promptly; for people at high risk of infective endocarditis, the March 2026 SDCEP pathway offers prophylaxis for dental extraction/oral surgery and uses shared decision-making for procedures that manipulate gingiva or the periapical region.
Pregnancy may be extremely high risk in pulmonary arterial hypertension/Eisenmenger syndrome, severe ventricular dysfunction or major aortopathy; pre-conception ACHD–maternal medicine review is essential.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Developmental cardiac malformation

Abnormal septation, valve formation, outflow alignment or aortic-arch development creates shunts, obstruction or abnormal connections. Most lesions reflect interacting genetic and developmental influences.

Familial or syndromic susceptibility

Some defects cluster in families or accompany chromosomal and multisystem syndromes. Recognising this context informs genetic counselling, screening and assessment of extracardiac needs.

Residual disease after repair

Childhood surgery or catheter treatment may leave valve regurgitation, residual shunt, conduit dysfunction, scar or altered ventricular loading. These can become clinically important decades later.

Unrepaired or palliated complex physiology

Persistent shunts, cyanotic connections, Fontan circulation or a systemic right ventricle expose adults to chronic pressure, volume or oxygenation stress despite apparent early stability.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Abnormal anatomy alters flow
A shunt redirects blood between circulations, an obstruction raises upstream pressure, and an abnormal connection changes oxygen delivery. The exact anatomy determines which chambers bear the load.
2
Chambers remodel
Chronic pressure or volume loading causes hypertrophy, dilatation and eventual ventricular or valve dysfunction. Right- and left-sided lesions therefore produce distinct trajectories and examination findings.
3
Pulmonary vascular disease may emerge
A longstanding large left-to-right shunt increases pulmonary flow and pressure, promoting pulmonary vascular remodelling. If pulmonary vascular resistance becomes sufficiently high, the shunt can become bidirectional or reverse, causing cyanosis and Eisenmenger physiology.
4
Repair creates new physiology
Patches, baffles, conduits and surgical scars can obstruct, leak or form arrhythmic circuits. A repaired heart may therefore have anatomy and risks unlike either a normal or unrepaired heart.
5
Reserve declines over time
Valve deterioration, ventricular fibrosis, pulmonary vascular disease and recurrent arrhythmia progressively reduce exercise and haemodynamic reserve. Pregnancy, infection or surgery may expose this vulnerability.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Acute deteriorationRed flag

New cyanosis below baseline, syncope, sustained tachyarrhythmia/bradyarrhythmia, pulmonary oedema, low-output state, haemoptysis, focal neurology or fever with possible endocarditis.

Shunt or valve lesion

Murmur, fixed split second sound, RV heave, chamber enlargement, unexplained dyspnoea, exercise limitation or embolic event; physiology and pulmonary pressures determine whether closure is safe.

Coarctation/aortopathy

Upper-limb hypertension, diminished/delayed femoral pulses, arm-leg systolic gradient at least 20 mmHg, interscapular murmur, bicuspid valve or aortic enlargement.

Repaired tetralogy of Fallot riskRed flag

Palpitations, syncope, NSVT, QRS prolongation, declining exercise capacity, RV dilation/dysfunction or severe pulmonary regurgitation can precede ventricular arrhythmia or heart failure.

Eisenmenger/hyperviscosityRed flag

Central cyanosis, clubbing, erythrocytosis, headache, visual disturbance, dizziness, thrombosis or bleeding. First exclude dehydration and iron deficiency before attributing symptoms to hyperviscosity.

High-risk pregnancyRed flag

Pregnancy or pregnancy planning with pulmonary arterial hypertension/Eisenmenger physiology, severe ventricular dysfunction, Fontan failure or significant aortopathy needs urgent specialist counselling; PAH is a very high maternal-risk state.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Retrieve operative/interventional records, baseline ECG and saturationFirst step
Why
Define anatomy and the patient's normal physiology before labelling a new abnormality.
Interpretation and limitations
Unknown anatomy or complex repair is itself a reason for ACHD-centre input; compare current saturation and rhythm with baseline.
02
12-lead ECG and ambulatory rhythm monitoring
Why
Detect conduction disease and scar-related atrial or ventricular arrhythmia.
Interpretation and limitations
Choice and duration follow symptom frequency; repaired TOF risk assessment includes QRS duration, NSVT and ventricular function.
03
Transthoracic echocardiographyFirst line
Why
First-line assessment of anatomy, ventricular function, valves, gradients, shunts and estimated pulmonary pressure.
Interpretation and limitations
Echo drives further testing but may not quantify the RV, Fontan pathway or extracardiac vessels reliably.
04
CMR
Why
Reference method for RV volumes/function, shunt flow, pulmonary arteries, aorta and serial repaired-TOF assessment.
Interpretation and limitations
In repaired TOF, progressive RV end-diastolic volume index at least 160 mL/m² or end-systolic volume index at least 80 mL/m² supports pulmonary-valve intervention assessment when severe pulmonary regurgitation/other criteria are present.
05
Cardiac CT
Why
Define coronary anatomy, calcified conduits, stents and aorta when CMR is unsuitable or procedural planning needs higher spatial resolution.
Interpretation and limitations
Balance radiation/contrast against the clinical question, especially in young adults needing lifelong imaging.
06
Cardiopulmonary exercise testing
Why
Objectively measure functional capacity, chronotropic response and serial deterioration.
Interpretation and limitations
Falling peak oxygen uptake or abnormal BP/rhythm response may trigger further lesion-specific assessment even when symptoms are understated.
07
Cardiac catheterisation
Why
Measure pulmonary pressures/PVR, shunt and gradients when non-invasive data are uncertain or intervention is planned.
Interpretation and limitations
For a shunt with estimated systolic pulmonary pressure above 40 mmHg or suspected pulmonary vascular disease, invasive PVR guides whether closure is safe.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Acquired valve or myocardial disease

Hypertension, coronary disease, degenerative valve disease and acquired cardiomyopathy can cause similar murmurs, arrhythmia or heart failure. Prior anatomy and operation records prevent misattribution to congenital disease.

Primary pulmonary disease or embolism

Lung disease and PE can cause dyspnoea, hypoxaemia and right-heart strain. A change from baseline saturation, acute pleuritic symptoms or vascular imaging helps identify an acquired pulmonary cause.

Primary pulmonary arterial hypertension

Pulmonary hypertension without a significant shunt may resemble shunt-associated vascular disease. Expert imaging and catheter haemodynamics define anatomy, resistance and whether closure would be harmful.

Infective endocarditis

Fever, embolic features, a new murmur or unexplained decompensation in repaired or unrepaired disease should raise suspicion. Blood cultures and expert echocardiography distinguish infection from chronic baseline abnormalities.

Iron deficiency or dehydration in cyanosis

Headache, dizziness and fatigue may be labelled hyperviscosity, but iron deficiency or volume depletion often contributes. Blood indices and hydration assessment should precede invasive viscosity-reducing measures.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Emergency / protocol-dependentThe unwell ACHD patientFirst stepNew cyanosis, syncope, arrhythmia, heart failure, chest pain, haemoptysis, neurological deficit or sepsis.

1Use ABCDE, monitoring, 12-lead ECG, IV access and syndrome-directed resuscitation while contacting the regional ACHD centre early; retrieve the anatomy/operation record and baseline saturation.
2Use meticulous air-free IV technique and filters when a right-to-left shunt is possible. Avoid abrupt preload loss or systemic vasodilation in Fontan/cyanotic physiology without expert advice.
3Treat immediately reversible standard emergencies, but discuss cardioversion, pacing, ventilation, vasoactive drugs and invasive procedures with ACHD/anaesthesia teams because anatomy and access may be non-standard.
4Transfer to an ACHD-capable centre when complex physiology, sustained arrhythmia, decompensation, endocarditis or a procedure requiring specialist anatomy is present.

02ESC lesion-specificAtrial septal defectSecundum or surgical ASD with right-ventricular volume overload or symptoms.

1Use TOE before device closure to define rims, defect size and anomalous pulmonary venous return; CMR/CT can quantify RV and shunt anatomy.
2PreferredDevice closure is preferred when secundum anatomy is suitable, commonly stretched diameter no more than about 38 mm with adequate rims; surgery treats unsuitable anatomy or associated lesions.
3PVR below 5 Wood units generally permits closure when indicated. At PVR at least 5, start expert PAH therapy and reassess; consider only fenestrated closure if PVR falls below 5 with a significant left-to-right shunt. Avoid closure in persistent severe pulmonary vascular disease/Eisenmenger physiology.
4After device closure, give aspirin 75 mg once daily for at least 6 months and perform specialist follow-up for device position, residual shunt and arrhythmia.

03ESC lesion-specificCoarctation and repaired tetralogy of FallotUpper-limb hypertension/recoarctation or repaired TOF with pulmonary regurgitation/RV change.

1Coarctation: measure right-arm ambulatory BP and leg BP; use CMR or CCT to assess the entire aorta. Confirm a significant invasive peak-to-peak gradient, often at least 20 mmHg, when intervention is being considered.
2Refer significant native/recoarctation for ACHD aortic-team intervention even if resting BP is normal when anatomy/gradient is compelling. Continue annual clinical follow-up and aortic imaging commonly every 3–5 years.
3Repaired TOF: use serial CMR and CPET. Pulmonary-valve replacement assessment is indicated with symptoms or progressive RV dilation/dysfunction, severe pulmonary regurgitation, worsening TR or exercise decline; RVEDVi at least 160 or RVESVi at least 80 mL/m² are important thresholds.
4Assess ventricular-arrhythmia/SCD risk using ventricular dysfunction, NSVT, syncope, QRS at least 180 ms, scar and inducibility; ICD decisions belong to ACHD electrophysiology.

04ACHD/PAH specialistEisenmenger syndromePulmonary vascular disease with bidirectional/right-to-left shunting and cyanosis.

1EscalationManage in a combined ACHD-pulmonary-hypertension service. Begin or sequence oral PAH therapy according to symptoms and risk—commonly an endothelin-receptor antagonist or PDE5 inhibitor—and escalate when response is inadequate.
2Do not close the shunt. Do not perform routine venesection; consider isovolumic phlebotomy only for moderate/severe hyperviscosity symptoms with haematocrit above 65% after correcting dehydration and excluding iron deficiency.
3Do not prescribe oxygen routinely; use it when testing shows a sustained improvement in saturation and symptoms. Anticoagulation is not routine because thrombosis and major bleeding coexist.
4EscalationAvoid pregnancy and oestrogen-containing contraception; use specialist contraceptive counselling. For parenteral PAH escalation, the expert team may prefer subcutaneous or inhaled routes to reduce line-related paradoxical embolus/infection risk.

05NICE preventionEndocarditis and proceduresStructural congenital heart disease or prosthetic material before dental/other procedures or with infection.

1Explain endocarditis symptoms and the importance of oral hygiene, regular dental care, skin care and prompt assessment of unexplained fever.
2NICE does not recommend antibiotic prophylaxis routinely for dental, upper/lower GI, genitourinary or respiratory procedures solely to prevent endocarditis.
3For people at high risk of infective endocarditis, follow the March 2026 SDCEP pathway: offer prophylaxis for dental extraction or oral surgery, and use shared decision-making for procedures that manipulate gingiva or the periapical region. Involve cardiology and dentistry when anatomy or prior endocarditis makes risk uncertain.
4Take blood cultures before antibiotics when endocarditis is suspected and the patient is stable enough; do not delay sepsis treatment in shock.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

Antiplatelet therapy while the device endothelialises.

Aspirin after ASD device closure

75 mg orally once daily for at least 6 months after device closure, unless the interventional ACHD plan specifies otherwise.

Active bleeding, aspirin hypersensitivity, major GI risk and interacting antithrombotics; duration and combination therapy are device/procedure dependent.

Specialist endothelin-receptor antagonist option for PAH, including selected Eisenmenger patients.

Bosentan

62.5 mg orally twice daily for 4 weeks, then 125 mg twice daily if tolerated.

Initiate only through a PAH-experienced service. Contraindicated in pregnancy and moderate/severe hepatic impairment; teratogenic, hepatotoxic and may cause anaemia/fluid retention. Hormonal contraception alone may be ineffective.

Specialist PDE5-inhibitor option for PAH/Eisenmenger treatment or sequential combination therapy.

Sildenafil for PAH

20 mg orally three times daily, approximately 6–8 hours apart.

Never combine with nitrates/nitric-oxide donors or riociguat. Avoid with severe hypotension below 90/50 mmHg, recent stroke/MI, severe hepatic impairment and specified potent CYP3A4 inhibitors.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Arrhythmia and sudden death

Chamber dilatation and surgical scar support atrial and ventricular re-entry. Palpitations, syncope or declining exercise capacity may precede sustained arrhythmia, haemodynamic collapse or sudden death.

Ventricular and valve failure

Chronic abnormal loading, systemic right-ventricular work or conduit and valve deterioration can cause progressive heart failure. Symptoms may appear only after substantial structural change.

Pulmonary hypertension and Eisenmenger syndrome

Irreversible pulmonary vascular remodelling can reverse a longstanding shunt, causing cyanosis, erythrocytosis and right-heart failure. Closing the pressure-relief pathway may then be dangerous.

Thromboembolic and neurological events

Atrial arrhythmia, prosthetic material or right-to-left shunting can permit intracardiac or paradoxical embolism. Stroke and systemic infarction risk varies considerably with lesion, rhythm and physiology.

Endocarditis and aortic complications

Abnormal valves, residual jets and prosthetic material can support infection. Selected lesions also carry progressive aortic dilatation or dissection risk, requiring lesion-specific lifelong surveillance.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Bosentan: LFTs before treatment and monthly, plus 2 weeks after dose increase; haemoglobin before treatment, monthly for 4 months then every 3 months; pregnancy testing before treatment and monthly where relevant.
Sildenafil: monitor BP, symptom response, vision/hearing adverse effects and interactions; explicitly check nitrate/riociguat use.
Use lesion-specific lifelong surveillance: ECG/echo, CMR/CT, exercise testing and rhythm monitoring at intervals set by ACHD complexity and serial change.
Coarctation: check right-arm clinic/ambulatory BP and image the aorta, commonly every 3–5 years even after repair.
Cyanotic disease: monitor saturation, FBC/haematocrit, ferritin/iron, renal function and urate; erythrocytosis is compensatory and does not itself justify venesection.
Before pregnancy or major non-cardiac surgery, document ventricular/valve/aortic status, arrhythmia risk, anticoagulation and a multidisciplinary delivery/anaesthetic plan.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Ask for the map

A one-line label such as repaired hole in the heart is insufficient. The operative diagram, residual lesions and ventricular connections can change every emergency decision.

Shunt closure can be dangerous

In advanced pulmonary vascular disease, the shunt may be a pressure-relief route. Closing it without PVR assessment can precipitate right-heart failure.

Cyanosis changes IV practice

Any venous air can cross a right-to-left shunt; meticulous de-airing and filters are simple safeguards.

High haematocrit is often adaptive

Routine phlebotomy worsens iron deficiency and oxygen delivery. Treat dehydration/iron deficiency first and reserve isovolumic venesection for strict symptomatic criteria.

Serial RV volume matters in repaired TOF

Symptoms can lag behind progressive RV dilation; CMR thresholds help time pulmonary-valve assessment before irreversible dysfunction.

Pregnancy risk is lesion-specific

A well-repaired simple lesion may be low risk, whereas PAH/Eisenmenger physiology is extremely high risk. Pre-conception review cannot be replaced by generic reassurance.

11Common pitfallsFrequent interpretation and management errors.

01
Assuming a childhood operation was curative and discharging a moderate/complex ACHD patient from surveillance.
02
Closing an ASD/VSD/PDA without expert pulmonary vascular resistance assessment when pulmonary pressure is raised.
03
Treating compensatory erythrocytosis with routine venesection.
04
Giving nitrates to a patient taking sildenafil for PAH.
05
Using unfiltered IV lines where a right-to-left shunt is possible.
06
Promising routine antibiotic prophylaxis for every dental procedure despite current NICE advice.
07
Discussing pregnancy only after conception in a patient with PAH, Fontan failure or aortopathy.