Congenital heart disease: tetralogy of Fallot, ASD, VSD, PDA

1Definition

Congenital heart disease (CHD) is a structural abnormality of the heart or great vessels present at birth. It is the commonest birth defect.

2Classification

3Causes and risk factors

• Most have no single cause.
• Genetic syndromes (Down syndrome, often with an atrioventricular septal defect), family history.
• Maternal rubella (PDA), diabetes, alcohol, some medicines, older maternal age.
• Prematurity (PDA).

4Tetralogy of Fallot: pathophysiology

The four parts (all from one developmental fault: the outflow septum is displaced forwards):

1. Ventricular septal defect (large).
2. Overriding aorta sitting over the VSD.
3. Right ventricular outflow tract obstruction (pulmonary stenosis).
4. Right ventricular hypertrophy (a result of the obstruction).

The narrowed outflow pushes deoxygenated blood from the right ventricle through the VSD into the aorta: cyanosis. The more severe the obstruction, the bluer the child.

5Clinical features

Tetralogy of Fallot (3 marks in W16)

• Cyanosis, often appearing in the first months of life and increasing with crying or exertion.
• Hypercyanotic ("tet") spells: sudden deep cyanosis, fast breathing, irritability, sometimes fainting or fits, often after waking, feeding or crying.
• Squatting after exertion in older children.
• Clubbing of fingers and toes; poor growth; exercise intolerance.
• Harsh ejection systolic murmur at the left upper sternal edge (from the pulmonary stenosis); single second heart sound.

Other lesions

• VSD: loud pansystolic murmur at the left lower sternal edge; large defects cause breathlessness, sweating on feeding and poor weight gain.
• ASD: often no symptoms until adulthood; fixed split second heart sound.
• PDA: continuous "machinery" murmur below the left clavicle; bounding pulses.
• Coarctation: weak, delayed femoral pulses; high BP in the arms.
• Eisenmenger syndrome: a long-standing left-to-right shunt causes pulmonary hypertension that reverses the shunt, so cyanosis appears late.

6Investigations

Radiological features of tetralogy of Fallot (3 marks in S21)

• Boot-shaped heart (coeur en sabot): upturned, rounded apex from right ventricular hypertrophy.
• Concave pulmonary bay (small pulmonary artery segment) on the left heart border.
• Oligaemic lung fields: reduced lung vessel markings, dark lungs.
• Heart size usually normal.
• A right-sided aortic arch in some patients.

Other tests

• Echocardiogram: the main diagnostic test for all lesions.
• ECG (right ventricular hypertrophy in TOF); pulse oximetry (newborn screening detects many critical lesions); haemoglobin (raised in chronic cyanosis); cardiac catheterisation or CT/MRI before surgery.

7Medical and surgical management

• TOF: complete repair in infancy (VSD patch closure and relief of the outflow obstruction); a temporary shunt (Blalock–Taussig) in some small infants.
• Tet spell first aid: calm the child, knee–chest position (or hold the baby with knees to chest), oxygen, and call for medical help; doctors may give morphine, fluids and other drugs.
• VSD, ASD, PDA: many small defects close on their own; device closure by catheter or surgical closure for larger ones; drugs to close a PDA in preterm babies.
• Transposition: arterial switch operation in the newborn period.
• Single-ventricle hearts: staged surgery (Glenn, Fontan).
• Heart failure medicines, nutrition support, endocarditis prevention, lifelong follow-up.

8Complications

• Heart failure, failure to thrive, repeated chest infections (left-to-right shunts).
• Polycythaemia, stroke, brain abscess (cyanotic lesions); infective endocarditis.
• Pulmonary hypertension and Eisenmenger syndrome.
• After repair: arrhythmias, leaking pulmonary valve (TOF), need for further surgery.
• Developmental delay; reduced exercise capacity.

9PT assessment (child after heart surgery)

• Diagnosis, operation, day, lines and drains, pacing wires, ventilation, oxygen and the child's target SpO₂ range (it may be lower than normal in cyanotic or palliated hearts).
• Breathing rate and effort, recession, chest expansion, auscultation, secretions, cough.
• Behaviour, pain (age-appropriate scale), developmental level, posture, shoulder movement.
• Parents' understanding and concerns.

10PT diagnosis by ICF (practice)

Practice case (not from a paper): a 3-year-old girl, day 2 after complete repair of tetralogy of Fallot. Impairments: sternotomy pain, reduced lung volumes, retained secretions, reduced mobility and fear. Activity: playing, walking, being lifted. Participation: play with family, nursery. Environment: anxious parents (barrier when they restrict movement), paediatric ICU team and play staff (facilitators). Personal: age and temperament.

11Goals

• Short-term: clear chest; normal breathing pattern for age; sitting, standing and walking within days; parents confident with handling.
• Long-term: normal developmental milestones; active play; age-appropriate exercise and sport as advised by the cardiologist.

12PT management after paediatric heart surgery

• Positioning: head of bed raised; side-lying; regular position changes. Avoid head-down positions.
• Airway clearance only when secretions are a problem: gentle manual techniques, assisted huffing, suction if needed; play-based deep breathing (blowing bubbles, windmills, party blowers).
• Early mobilisation: sitting out, standing, walking and play as soon as stable.
• Sternal care: lift the child with a scoop under the bottom and back rather than under the armpits for the first weeks; avoid pulling on the arms.
• Shoulder and trunk movement through play; posture.
• Developmental and play activities for infants; parent education and involvement.
• Later: encourage normal active play and fitness; individual advice on competitive sport.

13Precautions

• Know the child's target SpO₂; do not chase normal values in a cyanotic heart.
• Pulmonary hypertension: avoid crying, straining and drops in oxygen; handle calmly; pre-oxygenate before suction.
• Pacing wires and drains: secure before moving.
• Anticoagulated children: gentle handling.
• Cyanotic children: avoid dehydration (thick blood) and fatigue.

14Education for parents

• How to lift and handle the child after sternotomy; breathing games.
• Recognise a tet spell and the knee–chest position; when to seek help.
• Good dental hygiene (endocarditis prevention), vaccinations, follow-up appointments.
• Encourage normal play; avoid over-protection.

15Prognosis

Most children with repaired tetralogy of Fallot, ASD, VSD or PDA grow up to lead active lives, with lifelong cardiology follow-up. Complex single-ventricle hearts have a more limited exercise capacity.

16Exam corner

• W16 Q1(f), 3 marksClinical features of tetralogy of Fallot.
• S21 Q1(e), 3 marksRadiological features seen in tetralogy of Fallot.
• S26 Q1(f), 3 marksAny three clinical features of tetralogy of Fallot.

Technique cards for this topic: breathing exercises.

Keywords to underline

VSD, overriding aorta, pulmonary stenosis, RVH cyanosis tet spell squatting boot-shaped heart oligaemic lungs acyanotic vs cyanotic Eisenmenger