Hypoplastic Left Heart Syndrome: Looking Forward

Dec 17, 2014 | Suzanne Ferguson | @suzannerferguson

While science has made remarkable steps in treating patients with HLHS there is currently no cure. Most patients may face complications later in life, including heart arrhythmias, blood clots, developmental problems, and the possibility of future surgeries or a heart transplant. For more on this subject, please visit here.

At the Todd and Karen Wanek Family Program for HLHS at Mayo Clinic, we are making advancements every day to find new ways to treat HLHS through the use of four connected objectives: cell-based treatments, imaging and outcome, human genetics, and the creation of a biorepository. These advancements may delay and even prevent heart transplants for people with HLHS.

Cell-Based Treatments

Researchers believe stem cells can increase the strength of the heart, enabling it to pump blood through the body with greater power. By using cell-based therapies, team members are working to make the heart muscle stronger. This approach could possibly restore the right ventricle’s functional ability once it begins to decline or prevent the decline altogether.

The Todd and Karen Wanek Family Program for HLHS has initiated clinical trials offering the latest advances in cell therapy to people with HLHS. The goal of the trials is to determine how stem cells derived from different sources in the body, delivered at different times, can help HLHS children. In one clinical trial, umbilical cord stem cells are collected after birth and delivered directly into the heart muscle or intravenously during the Glenn procedure. Another study uses stem cells from a skin sample to be changed into heart-like cells. (Check out Nightline’s Bill Weir’s experience.)

Another use of stem cells includes comparing reprogrammed stem cells from children with HLHS and their unaffected parents to determine molecular differences in order to understand how HLHS develops.

Imaging and Outcome

To better understand HLHS and the predictors of long-term right ventricular performance, researchers are comparing medical histories of HLHS patients by using ultrasounds and MRI images of their hearts. In addition, researchers are also improving the ability to assess right ventricular function noninvasively to detect declines in cardiac function as soon as possible so they can intervene in a timely manner.

Human genetics

HLHS is likely caused by abnormal genes that result in the underdevelopment of the heart’s left ventricle. While those genes are currently unknown, researchers are analyzing whole-genome sequencing and bioinformatics to search for HLHS genetic variations. They are also attempting to detect changes in chromosomal material in people with HLHS.


By working with families to collect family histories, tissue and cell samples, genomic information and heart images of HLHS patients and their relatives, researchers are studying HLHS and creating a biorepository. The biorepository includes clinical and genetic data, as well as tissue and other physical specimens, which are used to further study HLHS and to explore new treatment options.   HLHS heart blocks labelled


The Todd and Karen Wanek Family Program for Hypoplastic Left Heart Syndrome (HLHS) is a collaborative network of specialists bonded by the vision of delaying or preventing heart failure for individuals affected by congenital heart defects including HLHS. The specialized team is addressing the various aspects of these defects by using research and clinical strategies ranging from basic science, to diagnostic imaging to regenerative therapies.

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