Single Ventricle Heart Defects

What is a single ventricle heart defect?

A child with a single ventricle defect is born with a heart that has only one ventricle that is large enough or strong enough to pump effectively. The heart typically has four chambers. The upper chambers, called atria, receive blood flowing into the heart. The lower chambers, called ventricles, pump blood out of the heart.

Single ventricle heart defects include:

  • Hypoplastic left heart syndrome (HLHS): a severe congenital heart defect in which the left side of the heart is underdeveloped
  • Tricuspid atresia: a condition characterized by poorly developed right heart structures; sometimes called hypoplastic right heart syndrome (HRHS)
  • Double outlet left ventricle (DOLV): a defect where both major arteries are connected to the left ventricle
  • Some heterotaxy defects
  • Other congenital heart defects

Single ventricle heart defects are also referred to as single ventricle lesions or anomalies.

Our newest video demonstrates the advances in heart care for babies with single ventricle heart defects — from before birth through childhood and into adulthood. Learn how early detection and diagnosis can make a world of difference in the lives of infants born with single ventricle heart defects.

Signs and symptoms of single ventricle heart defects

In most cases, children with single ventricle heart defects require intensive medical intervention soon after birth. Symptoms vary depending on the severity and type of heart defect, but typically include:

  • Blue or purple tint to lips, skin and nails (cyanosis)
  • Difficulty breathing
  • Difficulty feeding
  • Lethargy (sleepy or unresponsive)

Testing and diagnosis of single ventricle defects

Single ventricle heart defects are often diagnosed before your baby is born through fetal echocardiography. The Fetal Heart Program at CHOP will monitor baby and mother throughout the pregnancy and create a plan for labor and care after the birth.

The Fetal Heart Program team will also discuss possible delivery in the Garbose Family Special Delivery Unit (SDU). The SDU is on the same floor as the cardiac operating rooms and cardiac patient care units. Here, newborns can be in the care of pediatric cardiologists and specially trained cardiac nurses immediately. Parents are also able to remain in close proximity to baby after delivery. The Fetal Health team will talk to you about the optimal birth plan for your baby with a confirmed heart condition and if birth in CHOP’s SDU is recommended.

Sometimes single ventricle heart defects aren’t discovered or diagnosed until after your baby is born. Your newborn might look blue or have trouble breathing. The pediatrician at the birth hospital might hear a heart murmur (an abnormal sound in the heartbeat) and order an echocardiogram, which will show the defect. In these cases, newborns are transported to CHOP by ambulance or helicopter, and admitted to the Evelyn and Daniel M. Tabas Cardiac Intensive Care Unit (CICU). In the CICU, babies will receive around-the-clock attention from a team of dedicated cardiac critical care medicine specialists and specialty trained nurses and support staff.

Treatments for single ventricle heart defects

The various types of single ventricle heart defects are very different, and treatment for each must be customized.

For example, in hypoplastic left heart syndrome (HLHS), the left side of the heart doesn’t work correctly; while in tricuspid atresia, the right side doesn’t work correctly. Even though the types of defects are different, the general treatment approach for single ventricle heart defects is similar.

Single ventricle defects require a series of open-heart procedures, performed over several years. This is called “staged reconstruction” and includes three surgeries:

  • The Norwood procedure
  • The hemi-Fontan or Glenn operation
  • The Fontan procedure

During this series of operations, surgeons reconfigure the heart and circulatory system.

Your Cardiac Center team will explain the procedures to you in detail, based on your child’s heart anatomy. Your child will also be monitored between surgeries by the Infant Single Ventricle Monitoring Program.

Many patients with single ventricle defects may also require a cardiac catheterization during childhood. CHOP’s interventional cardiologists treat a high volume of single ventricle patients using catheterization. The Cardiac Center has also established a standard approach to assess these patients, which includes magnetic resonance imaging (MRI) and catheterization.

Life expectancy for single ventricle heart defects

Forty years ago, children with single ventricle heart defects didn’t survive past infancy. Today, because of advances in surgery, medicine and intensive care capabilities, the majority survive. There are now thousands of people in their 20s and 30s with Fontan circulation.

However, we still don't know the expected life span for these patients. As “single ventricle survivors” get older, doctors are recognizing that, while some do fine, many experience complications, including lung, liver and gastrointestinal diseases. The Cardiac Center at CHOP created the Single Ventricle Survivorship Clinic, part of the Fontan Rehabilitation, Wellness, Activity and Resilience Development (FORWARD) Program, to bring together doctors from different specialties to care for single ventricle survivors. The program is focused on the care of Fontan patients and conducts research into new treatments, quality of life and life span.

In addition, as a group, children with complex congenital heart defects who have had open heart surgery as infants are at a higher risk for neurodevelopmental issues when compared to children without congenital heart defects. The Cardiac Center at CHOP created the Cardiac Kids Developmental Follow-up Program to provide evaluation, screening and clinical care for children with complex congenital heart disease who are at risk for neurodevelopmental problems.

Follow-up care for single ventricle heart defects

Through age 18

Frequent appointments with your child’s cardiologist in infancy and early childhood are important to minimize risk factors associated with single ventricle heart defects. Your child will need a customized series of diagnostic tests between the planned stages of surgery.

Once the surgeries are complete, your child will have appointments with a pediatric cardiologist once a year or more frequently. It is also possible that your child will require additional surgical or catheter therapies, or in rare cases heart transplantation. 

Most children treated for single ventricle heart defects will not be required to take medication regularly, though some may need to take aspirin every day to “thin” their blood.

When it comes to physical activities, in most cases, parents are told to allow the child to do as much as they are  able to do. Most children will stop activities if they begin to stress their body. There are also certain sports and activities to avoid. Your child’s care team will discuss these with you based on your child’s unique situation.

Into adulthood

Children born with single ventricle heart defects that are treated with Fontan circulation must continue to see a cardiologist as an adult. CHOP’s Cardiac Center will help with the transition to an adult cardiologist.

The Philadelphia Adult Congenital Heart Center, a joint program of CHOP and the University of Pennsylvania, meets the unique needs of adults who were born with heart defects.

Reviewed by David J. Goldberg, MD

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