Single Ventricle Defects

Hearing your child has a single ventricle defect can be a shock. At the Mount Sinai Kravis Children’s Heart Center, we are here for you. We have a team of pediatric cardiologists along with multidisciplinary specialists who can diagnose this defect during pregnancy and prepare for treatment as soon as your infant is born. From fetal life through childhood and into adulthood, we are at your child’s side to provide the support and care needed for the best possible quality of life.

About Single Ventricle Defects

In a single ventricle defect, the heart has only one functioning ventricle (pumping chamber) instead of two. A normal heart has one ventricle that pumps blood to the lungs to become oxygenated, and another ventricle that pumps the oxygenated blood to the body.

There are many different types of single ventricle defects, and they are often associated with other heart and blood vessel conditions. Single ventricle defects may also include:

  • Double inlet left ventricle
  • Forms of the pulmonary valve defect (pulmonary atresia) with no connection between the right and left ventricles (intact ventricular septum)  
  • Hypoplastic left heart syndrome
  • Tricuspid atresia
  • Unbalanced atrioventricular canal defect


Symptoms of a single ventricle defect vary, but may include:

  • Difficulty breathing
  • Difficulty feeding
  • Limited exercise tolerance
  • Low oxygen levels causing blue lips, skin, and nails
  • Poor weight gain


An early diagnosis of your infant’s single ventricle heart defect is important. We can diagnose this condition during a fetal echocardiogram, making it possible for us to monitor your pregnancy and delivery so that mother and baby can receive the best possible care. The doctors and nurses of Mount Sinai’s Fetal Heart Program are dedicated to treating your infant as early as possible.

To diagnose your child’s condition, we may perform the following tests: 

  • Cardiac catheterization—a minimally invasive procedure for diagnosis and sometimes treatment. It involves inserting a thin tube in a blood vessel in the leg to measure blood flow and pressure in the heart
  • Cardiac MRI—an imaging test that uses safe, powerful magnets and radio waves to create pictures of the heart
  • Chest X-ray—an approach that takes pictures of the heart, lungs, and blood vessels to show if the heart is enlarged
  • Echocardiogram (also called an echo or cardiac ultrasound)—a safe, noninvasive procedure that uses ultrasound waves to create an image of the size, shape, and movement of the heart, valves, and chambers along with how blood flows
  • Electrocardiogram (ECG or EKG)—a noninvasive procedure that shows electrical activity by placing stickers on your child’s chest

Treatments We Offer

The surgical treatment for your child’s single ventricle depends on how your child’s heart is formed and how it functions. For example: 

  • If your child’s heart defect causes too little blood to get to the body, we may perform a series of operations starting in the newborn period, similar to the therapy for hypoplastic left heart syndrome.
  • If enough blood is going to the body, but not enough is reaching the lungs, surgery can increase the amount of blood going to the lungs. We do this by inserting a small tube called a Blalock-Taussig shunt.
  • If too much blood is going to the lungs, we may need to place a band around the pulmonary artery to limit blood flow and control symptoms of heart failure.
  • When the amount of blood going to the body and lungs is balanced, your newborn may not need immediate surgery, and we may be able to delay treatment until we perform the bi-directional Glenn operation.

With single ventricle heart defects, we usually perform surgeries such as the bi-directional Glenn shunt (at about four to six months) and Fontan procedure (at about two to three years).

Many children with the Fontan circulation need medication and repeat procedures. 

In all cases of single ventricle defects, your child will need lifelong care. For instance, we will monitor your child’s heart and circulation closely after the Fontan procedure. We do this to help prevent the altered blood flow patterns from causing blood clots, liver problems, or loss of protein and fluid.  

Why Choose Children’s Heart Center?

When it is time to diagnose and treat your child for an abnormal heart condition, the only place to be is a pediatric cardiology unit like the Children’s Heart Center. Here we have the dedication and experience to treat your newborn or child of any age. Our expertise is in treating complex congenital heart diseases like single ventricle defects. From our advanced cardiac imaging to outstanding pediatric cardiologists and pediatric cardiac surgeons, we are your partner in the care of your child.

We are here for you and your child for life.