hypoplastic left heart syndrome
Hypoplastic left heart syndrome (HLHS) is a cyanotic congenital cardiac anomaly where affected individuals can have profound cyanosis and cardiac failure.
It is one of the commonest causes for a neonate to present with congestive cardiac failure and the 4th most frequent cardiac anomaly to manifest within the 1st year of life . The presence of an atrial septal defect and/or persistent patent foramen ovale (PFO) is crucial in residual cardiac function . Hypoplastic left heart syndrome is fatal if untreated.
This anomaly is thought to represent 2-4% congenital cardiac anomalies . There is a recognized male predilection. The estimated incidence is ~ 1 in 10 000 births .
- genetic disorders
- concurrent aortic coarctation (67 to 80% )
- endocardial fibroelastosis
Hypoplastic left heart syndrome results from the underdevelopment of left heart structures including :
- left ventricle
- mitral valve: stenosis/atresia
- aortic valve: atresia/hypoplasia
- ascending aortic root/arch
- the overall cardiac silhouette may be small, normal or enlarged
- may also show evidence of pulmonary venous congestion
- the right atrial border may be prominent
The four chamber view is particularly helpful in initial in utero assessment. It may show a small ascending aorta, and a small but thick-walled left ventricle while the right heart chambers may appear enlarged. The movement of the mitral valve may also appear significantly impaired.
CT allows direct visualization of anomaly and vessel anatomy . Right-sided cardiac structures inclusive of the right ventricle, right atrium, and pulmonary trunk are often enlarged as a result of compensatory effect.
Allows direct visualization of anatomy, while SSFP sequences may be used to provide additional dynamic assessment.
Treatment and prognosis
Hypoplastic left heart syndrome can be well-tolerated in utero due to the fetal right ventricle being the dominant chamber and the ductus arteriosus being patent.
While previously uniformly fatal postnatally, the outlook has somewhat improved with new surgical strategies which include:
- Norwood procedure: most commonly performed initialpalliative procedure in the neonatal period
- bidirectional cavopulmonary anastomosis (BDCPA) or hemi-Fontan procedure
- cardiac transplantation
Prostaglandin E1 may be given as an initial management option to keep the ductus open.
General considerations include:
- infantile aortic coarctation (may also be an association)
- interrupted aortic arch: consider as a differential on a four-chamber fetal echocardiogram for the dilated fetal right ventricle
- Persistierender Ductus arteriosus
- congenital aortic stenosis
- Varianten der Herzanatomie
- causes of pulmonary arterial hypertension
- CXR approach to congenital heart disease
- chest x-ray appeoach to congenital heart disease
- congenital heart disease - chest x-ray approach
- endocardial fibroelastosis
- four chamber cardiac view
- fetal right ventricular enlargement
- Zyanotischer Herzfehler
- hypoplastic left heart syndrome with atrial septal defect