Single Ventricle Reconstruction Follow-Up 3 (SVR III)

(Completed Recruiting)

About This Study

This is a second follow-up of the Single Ventricle Reconstruction (SVR) trial which aimed to see which shunt type was best for infants with single ventricle heart defects undergoing the Norwood operation. The purpose of this study is to see which type of shunt is most effective by later school age.

Study Locations

Click on a pin to see study site location details

The Single Ventricle Reconstruction (SVR) trial aimed to see which shunt type was best for infants with single ventricle heart defects undergoing the Norwood operation. Children received one of two kinds of shunts; a modified Blalock-Taussig shunt (MBTS) or right ventricle to pulmonary artery shunt (RV-to-PA shunt) as part of that study.

Participants then had the option to enroll in the Single Ventricle Reconstruction Extension study (SVR II) as we aimed to learn how children 2-6 years of age do with each of these shunt types and to improve our understanding of the medical and surgical factors which influence health and development for children with single ventricle heart disease.

This is a continuation of the two previous SVR studies. The purpose of this study is to see which type of shunt placed at the time of the Norwood operation is most effective by later school age, beginning at 10 years of age. We want to learn if there are any long term differences in heart function, exercise ability, neurodevelopment, or quality of life between children who received a MBTS and those who received an RV-to-PA shunt.

This study is being performed with the support of the Pediatric Heart Network at all sites which participated in the original SVR trial. The study began in the summer of 2015 and ended the in-person study visits in September 2020.

This study is enrolling children who participated in the original SVR study. As a part of the SVR study cohort, your child is one of the largest groups of children with single ventricle heart disease, and has helped to answer important questions already.

The study will be explained to you in detail by one of the study investigators. Once your questions have been answered, you will be asked to sign an informed consent form to enter the study. If you give permission for your child to participate in this study, we will invite your child to come to the hospital where his or her heart surgery was done or to another closer hospital participating in this study.

During your visit your child will have:

  • Medical history, including height and weight measurement;
  • A cardiac magnetic resonance imaging (CMR);
  • A cardiac echocardiogram;
  • A bicycle exercise test; and
  • Neurodevelopmental testing including puzzles, games and paper and pencil tools to evaluate learning and development.

After the study visit, a member of the study team will contact you yearly until your child is 16 to update your child’s medical history data for the study.

Your child’s participation in the study will be from the time of the study visit until he or she turns 16.

Your child may receive no direct benefit from the study tests. However, the possible benefits of participation are as follows:

  1. You and your child will learn about how your child is learning and developing. If there are areas in which your child is having difficulty, these can be identified and recommendations for further evaluation or intervention provided, as appropriate.
  2. Your child’s cardiac MRI will be reviewed by a cardiologist. We will communicate to you any abnormal findings and forward the results to your child’s primary care physician with your permission. Further referrals to appropriate clinicians will be made as appropriate.
  3. It is possible that the clinical assessments obtained for research purposes, including the cardiac MRI, echocardiogram, exercise test and neurodevelopmental evaluation, may reveal important clinical findings.
  4. There might be an indirect benefit from the awareness that through your participation, these study results may help to improve the care of children with similar problems in the future.

Cardiac Magnetic Resonance Imaging (CMR):

MRI uses a powerful magnet to make images. Therefore, persons with metal implants, such as certain types of surgical clips or pacemakers should not have an MRI. In addition to a large magnet, the MRI scanner also uses radio frequency waves that can, on rare occasions, cause a mild warming sensation similar to what you feel on a warm day at the beach. The MRI scanner makes loud banging noises during the scanning session. During the MRI study earplugs will be provided to reduce the noise heard from the scanner. Mild nerve and muscle twitching in the arms and legs are extremely rare but possible. Some people simply find it uncomfortable and/or claustrophobic to lie in the close space of the MRI scanner.

Although there are no known long-term harmful effects from having an MRI scan performed, it is always possible that there are long-term effects that are not presently known.

During the MRI procedure, wires may be attached to monitor breathing and heart rate. On very rare occasions the presence of such wires has resulted in burns at the site of skin contact. Proper placement and use of the wires greatly minimizes this risk and the technologists have been trained in this procedure so that the probability of a skin burn from the wire contacts is very small.

We will not perform this test if sedation is necessary.

Exercise Testing:

Exercise testing for this study will involve pedaling on a stationary bike at increasing intensity. A small number of individuals who have had a Fontan operation develop an abnormal heart rhythm with strenuous exercise. A member of the exercise testing team will be present throughout the test to continuously monitor heart rhythm and how the child is doing.


There are no known risks to having an echocardiogram.

Neurodevelopmental Testing:

The neurodevelopmental testing will require approximately 5 to 6 hours. During this time there is a small chance that a child will feel frustrated by some of the evaluation but the person who will be conducting the testing is trained to work with children on these activities and will help avoid any frustration.

There will be no extra costs to you when you join this study. You must pay for all other costs related to your normal medical care such as hospital stays, surgery, drugs, lab tests, and doctor’s fees which are thought to be standard medical care for patients with your condition.