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 commonest cardiac anomaly to manifest within the 1st year of life1. The presence of ASD and/or Persistent patent foramen ovale (PFO) is crucial in residual cardiac function1. It is lethal if untreated.


Thought to represent 2 - 4 % congenital cardiac anomalies 3. There is recognised male predilection.


Results from under development of left heart structures inclusive of 5

* left ventricle
* mitral valve : stenosis / atresia
* aortic valve : atresia / hypoplasia
* ascending aortic root / arch

Radiographic features

Plain film

* the overall cardiac silhouette may be small, normal or enlarged 1.
* may also show evidence of pulmonary venous congestion.
* the right atrial border may be prominent


Allows direct visualisation of anomaly and vessel anatomy 2. 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 visualisation of anatomy while SSFP sequences may give added dynamic assessment.

Echocardiography / ultrasound

Four chamber view is particularly helpful in initial in-utero assessment. May show a small ascending aorta, and a small but thick walled left ventricle while the right heart chambers may appear enlarged.


* localised concurrent aortic coarctation (can be association in a majority of cases)
* endocardial fibroelastosis

Treatment and prognosis

Previously uniformly fatal. Outlook has somewhat improved with new surgical strategies which include

* Norwood procedure : most commonly performed initial palliative procedure in neonatal period 5
* bidirectional cavopulmonary anastomosis (BDCPA) or hemi-Fontan procedure
* cardiac transplantation

Author : Dr Yuranga Weerakkody, Radiopaedia


* 1. Bardo et.al, Hypoplastic Left Heart Syndrome, RadioGraphics, 21, 705-717, May 2001
* 2. R. C. Gilkeson et.al, Multidetector CT Evaluation of Congenital Heart Disease in Pediatric and Adult Patients, AJR 2003; 180:973-980
* 3. Barboza et.al, Prenatal Diagnosis of Congenital Cardiac Anomalies: A Practical Approach Using Two Basic Views, RadioGraphics, 22, 1125-1138, September 2002
* 4. O'Kelly and Bove ; Hypoplastic left heart syndrome : BMJ.1997; 314: 87
* 5. Bahaaldin Alsoufi, MD et.al, New Developments in the Treatment of Hypoplastic Left Heart Syndrome,

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