Congenital heart disease is a structural heart defect present at birth and the most common birth defect (about 1 in 100 live births). Risk factors include chromosomal syndromes (Down syndrome — atrioventricular septal defect; Turner syndrome — coarctation), maternal diabetes, maternal rubella, alcohol and some drugs in pregnancy, and family history.
Transition at birth. Before birth, blood bypasses the lungs through the foramen ovale and ductus arteriosus. With the first breaths, pulmonary resistance falls, left-sided pressure rises, the foramen ovale closes, and the ductus arteriosus constricts over the first days. Some defects only become visible when these channels close — and some ("duct-dependent" lesions) depend on the ductus to survive.
Classification by blood flow
| Group | Physiology | Examples | Key features |
|---|
| Increased pulmonary blood flow (acyanotic) | Left-to-right shunt: oxygenated blood recirculates to the lungs | Ventricular septal defect (VSD, most common), atrial septal defect (ASD), patent ductus arteriosus (PDA), atrioventricular septal defect (AVSD) | Murmur, heart failure, frequent respiratory infections, poor growth; no cyanosis (unless late pulmonary hypertension reverses the shunt — Eisenmenger syndrome) |
| Obstruction to ventricular outflow (acyanotic) | Pressure load on a ventricle | Coarctation of the aorta (CoA), pulmonary stenosis (PS), aortic stenosis (AS) | Murmur; CoA: higher BP and strong pulses in the arms, weak or absent femoral pulses and lower BP in the legs; AS: fatigue and exercise intolerance, chest pain or fainting with exertion in severe cases |
| Decreased pulmonary blood flow (cyanotic) | Obstruction to lung flow plus a defect that lets blue blood cross right to left | Tetralogy of Fallot (TOF), tricuspid atresia | Cyanosis, hypoxemic spells, polycythemia, clubbing |
| Mixed blood flow (cyanotic) | Oxygenated and unoxygenated blood mix | Transposition of the great arteries (TGA), truncus arteriosus, total anomalous pulmonary venous return, hypoplastic left heart syndrome (HLHS) | Cyanosis in the first hours or days, heart failure; TGA and HLHS are duct-dependent |
Tetralogy of Fallot has four features: VSD, pulmonary stenosis, overriding aorta, right ventricular hypertrophy. The degree of pulmonary stenosis decides how blue the child is. Hypercyanotic ("tet") spells occur when crying, feeding, or straining increases right-to-left shunting.
Heart failure in infants usually results from large left-to-right shunts (VSD, AVSD, PDA) or obstructive lesions. Features differ from adults.
Infant heart failure
- Tachypnea, grunting, retractions; tachycardia
- Sweating and tiring during feeds, taking a long time to feed, poor weight gain
- Hepatomegaly (the main sign of systemic venous congestion in infants — peripheral edema is uncommon)
- Frequent respiratory infections, pale or mottled skin
Cyanotic disease
- Central cyanosis (lips, tongue) that does not improve with oxygen
- Squatting in older children with TOF (raises systemic resistance)
- Clubbing, polycythemia (high hematocrit), exercise intolerance
- Tet spell: sudden deep cyanosis, rapid deep breathing, irritability, then limpness or loss of consciousness; the murmur may soften
Perfusion assessment (any child with suspected shock or poor cardiac output)
- Capillary refill (normal 2 seconds or less), pulse quality in central vs peripheral sites, skin color and temperature (cool hands and feet with a warm trunk), mental status, and urine output
- Weak, thready peripheral pulses and tachycardia appear before hypotension
- Compare arm and leg blood pressure and pulses (four-extremity BP) when CoA is possible
Approximate heart rates (awake)
| Age | Beats/min |
|---|
| Neonate | 100–205 |
| Infant | 100–180 |
| Toddler | 98–140 |
| Preschool | 80–120 |
| School age | 75–118 |
| Adolescent | 60–100 |
| Test | Key points |
|---|
| Newborn pulse oximetry screening for critical CHD | Done after 24 hours of age on the right hand and one foot. Pass: 95% or more in either site and a difference of 3% or less. Fail: below 90% in either → urgent evaluation. Readings between (90–94% or a difference over 3%) are repeated once |
| Echocardiogram | Main diagnostic test; fetal echo detects many defects before birth |
| ECG | Hypertrophy, rhythm problems |
| Chest X-ray | Heart size and pulmonary blood flow; "boot-shaped" heart in TOF, "egg on a string" in TGA |
| Cardiac catheterization | Pressures, oxygen levels, anatomy; also used for interventions (balloon valvuloplasty for PS or AS, device closure of ASD, PDA, some VSDs) |
| Hyperoxia test | Oxygen barely raises PaO₂ in cyanotic heart disease, unlike lung disease |
| CBC | Polycythemia and iron deficiency in cyanotic children |
- Keep the ductus open in duct-dependent lesions: prostaglandin E₁ (alprostadil) infusion until surgery
- Close a PDA in preterm infants: ibuprofen, indomethacin, or acetaminophen; device or surgical closure if they fail
- Heart failure: diuretics, ACE inhibitor, sometimes digoxin; high-calorie feeds; treat anemia; oxygen as ordered
- Catheter interventions: balloon valvuloplasty (PS, AS), balloon or stent for CoA, device closure (ASD, PDA)
- Surgery: many small VSDs close on their own; larger VSDs, TOF (complete repair usually in the first year), TGA (arterial switch in the first weeks), and staged palliation for single-ventricle hearts (HLHS)
- Tet spell: knee-chest position, calm, oxygen, then morphine, IV fluid bolus, phenylephrine; propranolol may be used for prevention
- End-stage heart disease: heart transplantation with lifelong immunosuppression
- Infective endocarditis prophylaxis before dental procedures that manipulate the gums is only for highest-risk children: unrepaired cyanotic CHD (including palliative shunts), the first 6 months after repair with prosthetic material or a device, residual defects next to prosthetic material, prosthetic valves, prior endocarditis, and heart transplant with valve disease. An isolated VSD, ASD, or PDA does not need prophylaxis; excellent oral hygiene is recommended for all
Drug safety (doses weight-based, calculated in mcg or mg/kg, and double-checked against a pediatric reference)
| Drug | Key safety points |
|---|
| Digoxin | Count the apical pulse for a full 1 minute before each dose; hold and notify if below the ordered limit (commonly under 90–110/min in infants, under 70–85 in toddlers, under 60–70 in older children). Therapeutic level about 0.5–2 ng/mL (0.6–2.6 nmol/L), drawn just before a dose; early toxicity in children: vomiting, poor feeding, bradycardia, arrhythmias. Hypokalemia, hypercalcemia, and hypomagnesemia increase toxicity. Doses are tiny (mcg) — independent double check. If a dose is vomited or missed, do not give an extra dose |
| Furosemide | Hypokalemia, dehydration, hyponatremia; ototoxicity; daily weight, I&O, potassium |
| Spironolactone | Hyperkalemia — avoid potassium supplements unless ordered |
| ACE inhibitors (captopril, enalapril) | Hypotension (check BP before doses), hyperkalemia, kidney injury, cough, angioedema; contraindicated in pregnancy (adolescents) |
| Alprostadil (PGE₁) | Apnea (be ready to ventilate), fever, flushing, hypotension; do not interrupt the infusion |
| Indomethacin / ibuprofen (PDA) | Reduced urine output and kidney injury, GI bleeding, NEC, platelet dysfunction |
| Propranolol | Bradycardia, hypotension, hypoglycemia with masked symptoms, bronchospasm |
| Dopamine, other inotropes | Tachycardia, arrhythmias, hypertension — continuous ECG and BP; central line preferred; extravasation causes tissue necrosis |
| Immunosuppressants (after transplant) | Infection; nephrotoxicity and hypertension (tacrolimus, cyclosporine); drug levels; no live vaccines |
Listed in priority order.
- Oxygenation and perfusion
- Monitor SpO₂, RR, HR, work of breathing, color, capillary refill, and pulses; give oxygen as ordered when respiratory distress is present (use carefully in duct-dependent lesions and single-ventricle physiology — follow the prescribed SpO₂ target)
- Position semi-upright (infant seat) to ease breathing
- Tet spell: place the infant in knee-chest position (older child squats), stay calm and comfort, give oxygen, notify the provider; prepare morphine and fluids
- Reduce cardiac workload
- Cluster care, allow rest, respond quickly to crying, keep warm
- Nutrition
- Small, frequent feeds with a soft preemie nipple; limit feeds to about 20–30 minutes; gavage the rest if needed
- High-calorie formula or fortified breast milk as ordered; daily weight
- Fluids — strict I&O; watch for fluid overload in heart failure; prevent dehydration in cyanotic children (polycythemia increases thrombosis and stroke risk)
- Cardiac catheterization care
- Before: NPO per anesthesia rules (clear fluids up to 1–2 hours, breast milk 4 hours, formula 6 hours, solids 8 hours); record baseline pulses below the insertion site and weight
- After: check the insertion site for bleeding or hematoma and distal pulses, color, temperature, and capillary refill of the affected leg; keep the leg straight for the ordered period (often 4–6 hours); monitor vital signs, rhythm, and glucose (infants); apply pressure above the site and call for help if bleeding occurs
- After cardiac surgery
- Continuous ECG, arterial BP, SpO₂; watch for low cardiac output and arrhythmias
- Chest tubes: keep the system closed and below chest level with the water seal intact; monitor drainage color and amount hourly — report sudden increases, bright red drainage, or drainage above the ordered mL/kg per hour limit; report sudden stop of drainage with distress (possible tamponade)
- Pain control; turn, cough, deep breathing, and position changes when hemodynamically stable to prevent atelectasis
- Infection prevention and family support
- Routine immunizations on schedule, plus influenza yearly; RSV protection (infant antibody or maternal vaccine) as recommended for all young infants
- Signs of heart failure to report: fast breathing, sweating with feeds, poor feeding, fewer wet diapers, puffy eyes, rapid weight gain
- Digoxin at home: use the provided syringe; count the pulse first if taught; give at the same times daily, 1 hour before or 2 hours after feeds; do not mix into food or a full bottle; keep locked away; call for vomiting, poor feeding, or slow pulse
- Tet spell at home: hold the infant in knee-chest position against your chest, stay calm, call emergency services if it lasts or the child becomes limp
- Good dental hygiene for all; ask whether dental antibiotic prophylaxis is needed (only highest-risk children)
- Activity: most children self-limit; follow cardiologist guidance on competitive sports
- After heart transplant: take immunosuppressants exactly on time, report fever or infection signs immediately, avoid sick contacts, no live vaccines
| Complication | What to watch for |
|---|
| Closing ductus in duct-dependent lesion | Sudden cyanosis or shock in the first 1–2 weeks |
| Heart failure | Tachypnea, hepatomegaly, poor feeding, weight gain |
| Hypercyanotic spell | Deep cyanosis, limpness, loss of consciousness |
| Stroke / thrombosis (cyanotic CHD) | Polycythemia with dehydration; new weakness or seizure |
| Infective endocarditis | Fever, new murmur, fatigue |
| Post-catheterization | Bleeding, hematoma, cool pulseless leg (arterial thrombosis), arrhythmias |
| Post-surgery | Low cardiac output, tamponade, arrhythmias, excessive chest tube drainage |
- Acyanotic left-to-right shunts (VSD, ASD, PDA, AVSD) → increased pulmonary flow and heart failure, no cyanosis; VSD is the most common defect
- CoA: BP and pulses higher in the arms than legs; weak femoral pulses
- TOF: VSD, PS, overriding aorta, RVH; tet spell → knee-chest position, oxygen, morphine
- Infant heart failure: tachypnea, sweating with feeds, hepatomegaly, poor weight gain
- Pulse oximetry screening after 24 hours, right hand and foot; pass 95% or more with difference 3% or less
- Digoxin: apical pulse 1 full minute; infant hold limit commonly under 90–110; vomiting is an early toxic sign; hypokalemia increases toxicity
- Furosemide → hypokalemia; ACE inhibitors and spironolactone → hyperkalemia
- PGE₁ keeps the ductus open — watch for apnea
- After catheterization: site bleeding and distal pulses, color, and temperature of the affected leg first
- Chest tube: keep water seal intact; watch drainage amount and color for hemorrhage
- Endocarditis prophylaxis only for highest-risk children — not for isolated VSD
Country Notes
United States
- Newborn pulse oximetry screening for critical CHD is part of the federal Recommended Uniform Screening Panel and is performed in nearly all states.
- Children with CHD follow the CDC/ACIP immunization schedule without delay, including yearly influenza vaccine.
Philippines
- Rubella immunization, which is covered by the Mandatory Infants and Children Health Immunization Act (RA 10152), prevents congenital rubella syndrome — a cause of PDA and pulmonary artery stenosis.
- Where newborn pulse oximetry screening is not available, careful newborn examination (color, pulses in all four limbs, murmurs, feeding) is essential before discharge.