Detection of congenital heart disease in mid-Essex

Congenital heart defects account for 3% of all infant deaths, with 18–25% of affected infants dying in the first year of life. Early (pre-symptomatic) identification helps improve outcome.1 Routine prenatal anomaly scans detect less than half of cardiac defects,2^,3 hence detection after birth remains important. Only families with a high risk of congenital heart defects are offered foetal echocardiography.

The UK National Screening Committee's newborn screening policy comprises clinical examination at birth and at 6–8 weeks, with specific cardiac investigations for high-risk children.4

We conducted a 3-year retrospective study in mid-Essex evaluating the detection of congenital heart defects, during postnatal and 6–8 week examinations from September 2004 to August 2007 on 55 infants born in mid-Essex with a confirmed diagnosis of congenital heart defects. Twenty infants identified either antenatally or diagnosed while admitted in the neonatal unit for other indications or detected by active case finding because comorbid conditions were excluded.

Results showed an incidence of 5.5/1000 live-births/year. Postnatal examination detected sixteen (45%) and GPs detected 13 infants (37%) during the 6–8 week check. Six infants with significant congenital heart defects were missed on screening and presented later with symptoms. Cyanotic lesions accounted for just under a quarter of all cases (23.6%). The most common acyanotic lesion was ventricular septal defect (29%). Six infants with significant cardiac lesions were missed on screening and presented at varying ages from 9 days to 7 months of whom four presented with cyanosis. Although all these infants survived, the increased morbidity, use of emergency care resources, and parental stress could be avoided by early detection.

Newborn physical examination is increasingly done in the first 24–48 hours of life by doctors in training and midwives. A congenital heart defect is likely to be missed because signs and symptoms are uncommon in the first few days, infants may look well initially, cyanosis is difficult to detect, and femoral pulses may be felt even in left ventricular obstructive lesions as a result of shunting.

Using echocardiogram as a screening tool would need enormous resources, would yield high false-positive rates, and is neither practical nor cost-effective. Results of a systematic review by Health Technology Assessment showed that clinical examination along with pulse oximetry had the highest detection rate with low false-positivity rates.4 The Pulseox study in the West Midlands is a large multicentre prospective study being conducted to assess diagnostic accuracy and cost-effectiveness of routine pulse oximetry to screen congenital heart defects.5

In our study, postnatal examination detected just under half of all infants with congenital heart defects. The 6–8 week infant check by GPs remains an important point of contact for patients as it detected more than a third of infants. The introduction of pulse oximetry as an aide to both these examination checks could increase detection.

• © British Journal of General Practice, 2010.