Hypoplastic Left Heart Syndrome

The heart normally has two sides, each with a collecting chamber (atrium) and pumping chamber (ventricle).  The right side of the heart collects blue (low oxygen) blood returning from the body. This blood is pumped to the lungs to collect oxygen. The left side of the heart collects pink (high oxygen) blood returning to the heart
from the lungs and pumps it to the body.

In some hearts, one of the two ventricles may be underdeveloped. In this case the ventricle is considered to be functionally single (and usually receives a mixture of pink and blue blood). In hypoplastic left heart syndrome (HLHS), the mitral valve, left ventricle, aortic valve and first part of the aorta are extremely small or have not developed at all. The right heart structures (atrium, ventricle and valves and the lung (pulmonary) artery) remain intact. Treatment can be a series of staged operations over 3-5 years, resulting in a Fontan circulation.

The major differences between HLHS and other forms of "single ventricle" are:

1. The remaining ventricle is the right ventricle, which takes over the role of pumping blood to the body although it is not designed to do such "heavy duty" work for a lifetime, and
2. The first operation to begin rearranging the heart "plumbing" is a very major one, and carries a higher than usual risk of failure and death.

The overall chance of a child surviving through all the necessary operations, having no other major complications, and being well and active at the conclusion of this series of procedures is less than for most other single ventricle heart abnormalities. The details are best understood through discussion with your paediatric cardiologist or cardiac surgeon.

The child being treated requires very close supervision between the first and second operation (bidirectional Glenn shunt at 3- 4 months of age), and sometimes this time is spent in hospital.

Treatment of HLHS is a major undertaking and although many families choose surgical treatment, for others there may be special reasons why they may decide against it. Families may discontinue a pregnancy (if the diagnosis is made before birth) or choose compassionate care for their baby after birth knowing this would
lead to certain death. It is a very difficult decision.

Once the Fontan Circulation is completed it allows close to normal levels of oxygen in the body to be achieved, improving well-being and considerably improving protection against certain complications such as stroke. The end result of this surgery is not to make the heart 'normal', but to help the heart and circulation work in the most efficient way possible. Children who have had this procedure will need ongoing care and medications, and sometimes problems can develop. If successful, children with this type of circulatory re-arrangement can live a good quality of life but with some restrictions and an ongoing need for medical supervision.

Disclaimer: This information is intended as a general guide only and not to provide specific information for individual patient care. Any questions about your own situation should be directed to your medical practitioner, or cardiac specialist. If you have questions regarding the information contained in this brochure please contact us.