Pediatric Heart Surgery: Treating Congenital Heart Defects in Babies and Children

A baby’s heart may sometimes develop with an abnormal structure before birth.

The abnormality can involve a hole between heart chambers, an incorrectly connected major artery, a narrowed valve or blood vessel, or a much more complex change in the way blood flows through the heart and lungs.

These conditions are called congenital heart defects or congenital heart disease (CHD).

Not every congenital heart defect requires surgery.

Some are small and may close or remain clinically insignificant. Others may require catheter-based treatment, medication, surgery, or a sequence of procedures beginning soon after birth.

The central challenge in pediatric cardiac surgery is therefore not simply to “repair a hole in the heart.”

The treatment has to restore or improve circulation while accounting for the child’s small size, developing organs, pulmonary circulation and long-term growth.

Bailey & Love describes congenital heart disease as a particularly important area of cardiac surgery because advances in cardiac surgery have substantially improved the survival and lifespan of patients with congenital disease.

What is congenital heart disease?

Congenital heart disease refers to structural abnormalities of the heart or great vessels that are present from birth.

The abnormality can involve:

• the cardiac chambers
• the septum between chambers
• heart valves
• the major arteries
• pulmonary veins
• the connections between the heart and great vessels
• the pathways through which blood reaches the lungs and systemic circulation

The resulting physiology depends on the exact anatomy.

Some defects increase blood flow to the lungs.

Others restrict blood flow.

Some allow oxygen-poor and oxygen-rich blood to mix.

Others cause the pulmonary and systemic circulations to run in parallel rather than normally in series.

This is why two children with “congenital heart disease” can have completely different symptoms and completely different treatment plans.

Cyanotic vs acyanotic congenital heart disease

One useful way of understanding congenital heart defects is to consider whether they produce cyanosis.

Bailey & Love broadly divides congenital cardiac lesions into cyanotic and acyanotic groups, while acknowledging that the distinction is not always absolute.

Cyanotic congenital heart disease

Cyanotic defects can reduce the amount of oxygenated blood reaching the systemic circulation.

Mechanisms include:

• right-to-left shunting
• reduced pulmonary blood flow
• abnormal connections between the systemic and pulmonary circulations
• complex defects that depend on mixing of blood

Bailey & Love identifies tetralogy of Fallot, transposition of the great vessels and total anomalous pulmonary venous drainage among important cyanotic congenital lesions.

Acyanotic congenital heart disease

Acyanotic defects may produce:

• increased pulmonary blood flow
• increased pressure load on the heart
• increased volume load on the heart
• obstruction of systemic or pulmonary blood flow

Examples include:

• atrial septal defect
• ventricular septal defect
• patent ductus arteriosus
• coarctation of the aorta
• selected valve abnormalities

Bailey & Love describes ASD, VSD and PDA as important left-to-right shunt lesions and aortic stenosis and coarctation as examples of obstructive lesions.

Why might a baby need heart surgery?

The need for surgery depends on what the abnormal anatomy is doing to the circulation.

A defect may require intervention when it causes:

• severe cyanosis
• inadequate blood flow to the lungs or body
• excessive pulmonary blood flow
• heart failure
• significant chamber enlargement
• severe valve obstruction
• progressive damage to the heart
• pulmonary vascular disease
• risk of serious complications if left untreated

Some defects are immediately life-threatening after birth.

Others may not cause obvious symptoms until infancy, childhood or even adulthood.

The timing of treatment is therefore determined by physiology rather than by a single age.

How are congenital heart defects discovered?

Some defects are identified before birth.

Others are discovered shortly after delivery.

Some are found months or years later.

Possible clues include:

• abnormal prenatal ultrasound
• abnormal fetal echocardiography
• cyanosis
• rapid breathing
• poor feeding
• sweating during feeds
• poor weight gain
• recurrent respiratory symptoms
• exercise intolerance
• a heart murmur
• abnormal pulses
• an abnormal oxygen saturation
• an unexpected finding on another investigation

Harrison’s notes that congenital cardiac anatomy and physiology require appropriate imaging and that echocardiography is central to defining many congenital lesions.

What is fetal echocardiography?

A fetal echocardiogram is a specialised ultrasound examination of the developing fetal heart.

It can provide more detailed assessment of cardiac structure than a routine obstetric ultrasound when there is an indication for targeted cardiac evaluation.

The purpose is not simply to predict whether a child will eventually need surgery.

Prenatal identification of a significant defect can allow:

• counselling of the parents
• planning of delivery
• arrangement of specialist neonatal care
• preparation for immediate treatment when necessary
• coordination between obstetrics, neonatology, cardiology and cardiac surgery

The exact prenatal pathway depends on the suspected lesion and local specialist services.

What tests are used after birth?

Evaluation may include:

Echocardiography

Echocardiography is usually central to diagnosis.

It can show:

• chamber anatomy
• septal defects
• valve structure
• ventricular function
• blood-flow patterns
• great-vessel connections

Electrocardiography

An ECG can provide information about:

• rhythm
• conduction
• chamber enlargement
• ventricular hypertrophy

Chest radiography

A chest X-ray can sometimes provide clues about:

• cardiac size
• pulmonary blood flow
• lung abnormalities

CT or MRI

Cross-sectional imaging can provide additional anatomical information when echocardiography does not fully answer the clinical question.

Cardiac catheterisation

Catheterisation may be required when detailed haemodynamic information is needed or when a catheter-based intervention is planned.

Harrison’s notes that cardiac catheterisation is not mandatory before every congenital cardiac operation when the anatomy is already well defined non-invasively and there is no reason to suspect associated coronary disease.

Ventricular septal defect: when a hole needs treatment

A ventricular septal defect (VSD) is an opening between the right and left ventricles.

It is one of the most common congenital cardiac abnormalities.

The clinical effect depends heavily on the size and location of the defect and the amount of blood passing through it.

A small VSD may have little haemodynamic consequence and can close spontaneously.

A large VSD can allow substantial blood flow from the left ventricle to the right ventricle and subsequently to the lungs.

This can produce:

• pulmonary overcirculation
• heart failure
• poor growth

Harrison’s notes that large VSDs can cause heart failure and poor somatic growth and are often closed before adulthood.

Treatment may involve:

• observation
• medical treatment of heart failure when necessary
• catheter-based closure in selected anatomy
• surgical closure

The appropriate option depends on the defect and the child’s clinical condition.

Atrial septal defect

An atrial septal defect (ASD) is an abnormal opening between the atria.

Because the pressure relationship between the atria usually favours flow from left to right, blood can pass from the left atrium to the right atrium.

Over time, a significant ASD can enlarge the right atrium and right ventricle because of increased volume flow.

Harrison’s identifies ASD as an important cause of right-heart dilation and notes that some large ASDs present in childhood while others remain undiagnosed until adulthood.

Treatment depends on:

• size and type of ASD
• amount of shunting
• right-heart enlargement
• pulmonary pressures
• symptoms
• suitability for catheter closure

Not every ASD needs surgical closure.

Patent ductus arteriosus

Before birth, the fetal circulation includes a vascular connection called the ductus arteriosus.

Normally, this closes after birth.

If it remains open, the child has a patent ductus arteriosus (PDA).

Blood can flow from the aorta toward the pulmonary arteries, increasing pulmonary blood flow.

Small PDAs may cause little or no haemodynamic disturbance, whereas larger defects can produce left-heart dilation and pulmonary vascular consequences. Harrison’s describes these differences in the natural history of PDA.

Depending on the child’s age, anatomy and clinical circumstances, treatment may involve:

• observation
• medication in selected neonates
• catheter-based closure
• surgical ligation or division

Tetralogy of Fallot

Tetralogy of Fallot (TOF) is one of the best-known cyanotic congenital heart defects.

Bailey & Love describes four principal abnormalities:

1. ventricular septal defect
2. overriding aorta
3. pulmonary outflow obstruction
4. right ventricular hypertrophy

The combination changes the way blood flows through the heart and can allow relatively oxygen-poor blood to reach the systemic circulation.

Children may develop:

• cyanosis
• breathlessness
• poor exercise tolerance
• hypoxic episodes
• fatigue

Bailey & Love describes echocardiography as confirming the diagnosis and surgical correction as the mainstay of treatment.

The exact timing and surgical strategy depend on the child’s anatomy and clinical status.

A repair typically involves closing the VSD and relieving the obstruction to pulmonary blood flow.

Importantly, repair is not necessarily the end of the child’s cardiac care.

Patients repaired for TOF may require lifelong congenital-cardiology follow-up because residual pulmonary valve disease, right ventricular enlargement, arrhythmias or other sequelae can develop later.

Harrison’s highlights the importance of ongoing assessment in patients with repaired congenital heart disease, including assessment of right ventricular size and function where relevant.

Transposition of the great arteries

Transposition of the great arteries (TGA) is fundamentally different from TOF.

In typical TGA:

• the aorta arises from the right ventricle
• the pulmonary artery arises from the left ventricle

This causes the systemic and pulmonary circulations to operate in parallel rather than in series.

Without adequate mixing between the two circulations, oxygenated blood cannot effectively reach the systemic circulation.

Bailey & Love describes TGA as a major cause of cyanosis in the newborn period and explains that survival initially depends on mixing through structures such as the foramen ovale, atrial septal defect or VSD.

This is why some newborns with TGA can become critically ill very soon after birth.

Initial stabilisation may involve measures to improve mixing and maintain appropriate circulation.

Bailey & Love describes balloon atrial septostomy and prostaglandin therapy as approaches used in neonatal stabilisation, with arterial switch repair as the standard surgical operation described in that edition.

The exact modern neonatal management pathway should be determined by a specialist congenital-heart team.

Coarctation of the aorta

Coarctation of the aorta is a narrowing of the aorta.

The effect depends on the location and severity of the narrowing and the child’s age.

Severe neonatal coarctation can compromise systemic blood flow.

Older children may present with:

• hypertension
• headaches
• reduced exercise tolerance
• differences in blood pressure between the upper and lower limbs
• diminished lower-limb pulses

Treatment can involve surgery or catheter-based intervention depending on anatomy and age.

Long-term surveillance remains important even after successful repair because hypertension, recurrent narrowing and aortic complications can occur.

Why do some children need more than one operation?

Congenital heart disease is not always a problem that can be completely corrected with one procedure.

Some hearts have anatomy that makes immediate complete repair unsafe or technically unsuitable.

In such cases, treatment may be staged.

A staged pathway may involve:

1. stabilising circulation
2. performing an initial palliative procedure
3. allowing the child to grow or physiology to change
4. performing a more definitive reconstruction
5. undertaking later interventions when required

This is particularly relevant to complex lesions involving a single functional ventricle.

Harrison’s describes Fontan-type pathways and the anatomy of staged single-ventricle circulation.

The important concept for families is that “surgery” can mean a treatment pathway rather than one isolated operation.

What is a Fontan circulation?

Some children are born with complex cardiac anatomy in which a conventional two-ventricle repair is not feasible.

These patients may ultimately undergo a Fontan-type operation.

The Fontan circulation redirects systemic venous blood toward the pulmonary arteries without using a conventional ventricular pump to drive that blood through the lungs.

Harrison’s illustrates different Fontan configurations, including extracardiac conduit and lateral-tunnel approaches.

A Fontan circulation is therefore not simply another type of routine congenital heart repair.

It creates a different long-term circulatory arrangement.

Children who undergo Fontan procedures require specialised lifelong follow-up.

What does pediatric heart surgery involve?

Many congenital cardiac operations use cardiopulmonary bypass (CPB).

CPB temporarily takes over the functions of the heart and lungs, allowing the surgeon to operate within the heart or great vessels.

Bailey & Love describes CPB as one of the fundamental developments that made modern cardiac surgery possible.

The surgical approach depends on the defect.

A conventional operation may involve a median sternotomy, while selected procedures can use less invasive approaches.

The actual operation might involve:

• closing a septal defect
• reconstructing a valve
• relieving an obstruction
• reconnecting great arteries
• constructing a conduit
• redirecting blood flow
• creating or modifying a shunt
• replacing or repairing a valve

There is therefore no single procedure called “pediatric heart surgery.”

The operation is designed around the child’s anatomy.

Can congenital heart defects be treated without surgery?

Yes.

Not every congenital cardiac intervention requires open surgery.

Depending on the defect, catheter-based procedures may be used.

Examples can include:

• closure of selected septal defects
• closure of selected PDAs
• balloon valvuloplasty
• balloon atrial septostomy
• stent placement
• selected transcatheter valve procedures

The decision depends on the lesion and the child’s anatomy.

Some defects are best treated surgically, some through catheter intervention, and some with a combination of approaches.

What happens after pediatric heart surgery?

Recovery depends heavily on the operation and the child’s condition before surgery.

Immediately after major cardiac surgery, a child may require intensive care.

Monitoring can include:

• heart rhythm
• blood pressure
• oxygenation
• ventilation
• cardiac function
• fluid balance
• kidney function
• bleeding
• infection

Children may initially require mechanical ventilation and medications to support circulation.

As the child stabilises, support is gradually reduced.

The eventual hospital stay depends on:

• the operation
• age
• underlying defect
• postoperative complications
• cardiac function
• feeding ability
• respiratory status

What complications can occur?

Pediatric cardiac surgery is complex, and complications can occur even when the operation is technically successful.

Potential complications include:

• bleeding
• infection
• arrhythmias
• low cardiac output
• respiratory complications
• kidney injury
• neurological complications
• residual or recurrent obstruction
• residual shunts
• valve dysfunction
• need for repeat intervention

The specific risks vary dramatically between different congenital defects and procedures.

A neonatal operation for a complex cyanotic defect should not be compared directly with elective closure of a simple septal defect.

Does successful surgery mean the child is cured?

Not always.

Some defects can be repaired with an excellent long-term result.

Others leave residual anatomical or physiological changes that require surveillance.

Even after a successful repair, a child may eventually develop:

• valve dysfunction
• residual shunting
• ventricular dysfunction
• arrhythmias
• obstruction
• aortic abnormalities
• exercise limitations

Harrison’s treats congenital heart disease as a lifelong field of care, with specialised adult congenital services becoming increasingly important as more children with repaired CHD survive into adulthood.

This is why successful childhood surgery and lifelong follow-up are not contradictory.

The operation may correct the major defect while the patient still requires monitoring for consequences of the original anatomy and repair.

Why is lifelong congenital-heart follow-up important?

A child who has undergone congenital cardiac surgery does not necessarily have the same cardiovascular anatomy as someone who was born with a completely normal heart.

Follow-up can monitor:

• ventricular function
• valve function
• residual defects
• pulmonary pressures
• rhythm
• exercise capacity
• aortic dimensions
• complications specific to the original repair

As children become adolescents and adults, their care may transition to a specialised adult congenital heart disease service.

Harrison’s highlights the development of specialised adult congenital-heart care as an important component of long-term management.

What should parents ask the pediatric cardiac team?

Before a planned operation, useful questions include:

1. What exactly is the heart defect?
2. How does the abnormal anatomy affect blood flow?
3. Why is intervention needed now?
4. Could the defect be treated through a catheter rather than open surgery?
5. Is this intended to be a complete repair or part of a staged pathway?
6. What will the operation change anatomically?
7. Will cardiopulmonary bypass be required?
8. What complications are most relevant for this particular operation?
9. How long is the expected hospital and intensive-care stay?
10. What follow-up will be required after discharge?
11. Will additional operations or catheter procedures potentially be needed later?
12. How will the child’s cardiac care transition into adolescence and adulthood?

Pediatric heart surgery is about physiology, not just anatomy

One of the most important differences between pediatric and adult cardiac surgery is that the child’s circulation is developing.

The same anatomical defect can behave differently depending on:

• age
• body size
• pulmonary vascular resistance
• ventricular function
• associated defects
• oxygen requirements
• timing after birth

This is particularly evident in newborns with complex cyanotic disease.

For example, TGA produces parallel circulations, while TOF produces cyanosis through a different anatomical mechanism.
The operation therefore has to address the physiology created by the anatomy, not merely the anatomical abnormality itself.

The key point

Pediatric heart surgery is not one operation and congenital heart disease is not one condition.

Children may have relatively simple defects such as selected ASDs, VSDs or PDAs, or complex abnormalities such as tetralogy of Fallot, transposition of the great arteries or single-ventricle physiology.

Some children need observation or catheter-based treatment.

Others require open surgery, sometimes urgently after birth.

And some children require a sequence of operations designed around their developing circulation.

The goal is not merely to perform an operation.

It is to establish the best possible circulation for the child’s anatomy, allow growth and development, and provide appropriate long-term congenital-cardiac follow-up.

Written and Reviewed By Dr. Munaf Ahmad Ansari

Medical information note: This article is written for information purpose only. Individual treatment decisions should be based on contemporary clinical guidelines and assessment by an appropriately qualified medical team.