What is single ventricle heart disease? 

Single ventricle heart diseases (SVHD) encompass a range of complex heart conditions in which only one of the heart’s two ventricles functions effectively. For many individuals with SVHD, through a series of carefully staged palliations, the flow of blood through the heart is reorganized to support the body in what's known as the Fontan circulation— a physiology that allows the single functional chamber to pump blood efficiently to the body. 

Thanks to extraordinary medical and surgical advances over the past 40 years, more people with SVHD are leading active and meaningful lives, while continuing to undergo lifelong specialized care. 

Who Receives the Fontan Surgery? 

Common congenital heart disease diagnoses which may be associated with SVHD include tricuspid atresia, hypoplastic left heart syndrome (HLHS), double inlet left ventricle, unbalanced atrioventricular septal (or canal) defect, and others.

Many individuals born with SVHD will receive the Fontan surgery as the last planned procedure in a series of two or three surgeries in the first several years of life. SVHD is a rare and complex congenital heart condition, representing one of the highest-risk forms of heart defects in newborns. Due to its rarity, even the largest children’s hospitals care for only a limited number of SVHD patients each year. While the condition requires urgent medical attention soon after birth, early intervention has enabled many children with SVHD to achieve improved survival and quality of life. A small number of children with SVHD will require heart transplants early in life, while the majority undergo a carefully staged series of three surgical procedures designed to support heart function and promote longevity:

• Stage I: In the first several months of life, it’s important for the body to have a balanced circulation such that the amount of blood flow to the lungs matches the blood flow to the rest of the body. The amount of blood flow to the lungs determines the baby’s oxygen levels and the blood flow to the rest of the body provides nutrients and oxygen to all the vital organs. Some babies are born with their circulation already balanced. Others will need an operation in the first several weeks of life to help get to a better balance. Common procedures include the Norwood Operation, aortopulmonary shunt, pulmonary artery band placement, or ductal stenting.

• Stage II (Glenn): Typically completed between 4–6 months of age; In the typical heart, the superior and inferior vena cavae normally carry the blue (deoxygenated blood) from the upper and lower parts of the body back to the heart. In this second operation, the Glenn procedure, the superior vena cava is connected directly to the pulmonary arteries so that blue blood from the upper body drains directly into the lungs, bypassing the heart. If a prior surgical shunt was performed, this shunt is taken down.

• Stage III (Fontan): Usually done between 2–4 years of age; The third step in the stages of single ventricle surgeries connects the inferior vena cava, the blood vessel that carries deoxygenated blood from the lower body, to the pulmonary arteries. The procedure allows all the blue blood returning from the body to bypass the heart and go directly to the lungs to pick up oyxgen. After the now red (oxygenated) blood returns to the heart, the single functional ventricle pumps it to the body.

With these life-sustaining interventions, many children with SVHD go on to thrive with close medical support. While some may still face challenges such as the need for home tube feeding, frequent follow-up care, and occasional hospitalizations, continued advances in care and management are helping more SVHD patients lead longer, more stable lives.