One idea that organizes the defects
Congenital heart defects are easier to remember as two functional groups than as a list of names. In left-to-right shunting lesions, higher-pressure oxygenated blood from the left side crosses into the right side and recirculates through the lungs. The child is not cyanotic, because oxygenated blood is going the wrong way rather than deoxygenated blood entering the systemic circulation, but the lungs and right heart are overloaded, producing heart failure and frequent respiratory infections. Ventricular septal defect, atrial septal defect and patent ductus arteriosus belong here.
In right-to-left or mixing lesions, deoxygenated blood reaches the systemic circulation, so the child is cyanotic. Tetralogy of Fallot is the classic example, combining pulmonary stenosis, right ventricular hypertrophy, an overriding aorta and a ventricular septal defect. Transposition of the great arteries and truncus arteriosus also produce cyanosis.
Obstructive lesions such as coarctation of the aorta present differently again: blood pressure is higher in the arms than the legs, with bounding upper-extremity pulses and weak or absent femoral pulses. Comparing four-extremity blood pressures is the assessment the exam expects you to name.
| Group | Examples | Hallmark |
|---|---|---|
| Increased pulmonary flow | VSD, ASD, PDA | Heart failure, murmur, no cyanosis |
| Decreased pulmonary flow | Tetralogy of Fallot, tricuspid atresia | Cyanosis, tet spells, clubbing |
| Mixed | Transposition, truncus arteriosus | Cyanosis with heart failure |
| Obstructive | Coarctation, aortic stenosis | BP higher in arms than legs, weak femoral pulses |
Recognizing heart failure in infants
Infants cannot report dyspnoea, so heart failure presents through feeding and growth. The most examinable early sign is diaphoresis during feeding: the effort of sucking is the infant equivalent of exercise, and sweating on the forehead during a feed is a classic finding. Tachypnoea at rest, nasal flaring, retractions, tachycardia, fatigue that shortens feeds, and failure to gain weight along the growth curve complete the picture. Hepatomegaly and periorbital oedema appear rather than the dependent leg oedema seen in adults.
Nursing care clusters around reducing cardiac workload while maintaining nutrition. Smaller, more frequent feeds with a soft or enlarged nipple shorten the work of each feed, feeds are limited to about 30 minutes with gavage supplementation if the infant tires, and daily weights on the same scale track both fluid status and growth. Clustering care and maintaining a neutral thermal environment reduce oxygen demand.
Expect items asking which finding to report. Weight gain over a short period, worsening tachypnoea, increasing respiratory effort and decreased urine output are all reportable, while a stable murmur that has been documented is not new information.
- •Sweating with feeds is an early infant heart failure sign
- •Limit feeds to about 30 minutes; supplement by gavage if needed
- •Daily weight, same scale, same time, minimal clothing
- •Cluster care to allow rest and reduce oxygen demand
Tet spells and cyanotic emergencies
A hypercyanotic or tet spell is an acute episode of worsening right-to-left shunting, usually triggered by crying, feeding or straining. The child becomes acutely cyanotic, irritable and tachypnoeic, and older children may squat instinctively. The immediate nursing action is to place the infant in a knee-to-chest position, which raises systemic vascular resistance and pushes blood back toward the pulmonary circulation, then administer oxygen and calm the child. Morphine and fluids may follow per orders.
Because the position is the intervention, this is one of the rare items where a positioning answer beats an assessment answer. Practise recognizing it so you are not tempted by 'obtain oxygen saturation' when the child is actively spelling.
Chronic cyanosis produces polycythaemia as the body compensates, which raises blood viscosity and the risk of thrombosis and stroke. Adequate hydration is therefore a genuine safety intervention, and dehydration from a simple illness is a reportable concern in these children.
Digoxin safety and Kawasaki disease
Digoxin is still used in paediatric heart failure and carries a narrow therapeutic range. Before each dose, count the apical pulse for a full minute and withhold the dose if the rate is below the age-based threshold, commonly 90 to 110 beats per minute in infants and 70 in older children, then notify the provider. Do not repeat a dose if the child vomits, and never mix digoxin into a bottle of formula because a partially finished bottle means an unknown dose. Early toxicity in children often presents as bradycardia, vomiting and anorexia, and hypokalaemia increases toxicity risk.
Kawasaki disease appears regularly because its management is counterintuitive. It is an acute vasculitis presenting with a fever lasting five days or more that does not respond to antipyretics, bilateral non-exudative conjunctivitis, a strawberry tongue with cracked lips, rash, extremity swelling with later peeling, and cervical lymphadenopathy. The feared complication is coronary artery aneurysm.
Treatment is intravenous immunoglobulin plus aspirin, making this one of the few paediatric conditions in which aspirin is deliberately used despite the usual Reye syndrome caution. Teaching includes that irritability is extreme and may persist for weeks, that peeling skin is expected, and that live vaccines must be delayed for about eleven months after immunoglobulin because it blunts the immune response.