Hitesh Aggarwal, MD
Overview
Hypoplastic left heart syndrome (HLHS) is a variant of congenital heart disease which is characterized by an underdevelopment of the left sided cardiac structures (mitral valve, left ventricle, aortic valve and aortic arch). In HLHS, the left side of the heart is unable so support the systemic circulation. Blood returning from the lungs must flow through an atrial septal defect. The right ventricle pumps the blood into the pulmonary artery and blood reaches the systemic circulation through a patent ductus arteriosus. There is severe hypoplasia of the left ventricular cavity with a dominant right ventricle and systemic outflow tract obstruction.
Epidemiology/Genetics
HLHS comprises 1.4-3.8% of all congenital heart disease. There is growing evidence to suggest a genetic etiology but so far, no specific genetic abnormality has been linked to HLHS. With one affected family member, there is about 2.2-13.5 % risk of recurrence of other congenital heart disease in the same family.
Anatomy / Classification
HLHS occurs in a spectrum ranging from
Other common congenital abnormalities
Clinical presentation
HLHS is usually diagnosed via prenatal ultrasound given the advancement in fetal echocardiography. Such patients get started on PGE postnatally to maintain ductal patency until stage I palliation can be performed. Fetuses with critical aortic stenosis (who may evolve into HLHS variants) may be candidates for fetal aortic valvuloplasty. Likewise, those with restrictive/intact atrial septum are candidates for placement of intra-atrial stent during fetal life in the immediate postnatal period.
Children born without a prenatal diagnosis can have variable clinical manifestations. Those with restrictive/intact atrial septum develop cyanosis and respiratory distress early on while those with a non-restrictive atrial communication can appear acyanotic initially and come to medical attention with closure of PDA and exhibit signs of poor systemic perfusion such as respiratory distress, pale, cool extremities, lethargy etc.
Goals of echocardiography
In general echocardiography provides all the anatomic details needed for surgical planning of patients with HLHS.
Parasternal long axis:
Parasternal short axis:
Apical four chamber view:
Subcostal view:
Suprasternal notch view: