For children diagnosed with complex heart conditions like hypertrophic cardiomyopathy (HCM), the diagnosis can be frightening for families and challenging for healthcare providers since the trajectory of the condition is often uncertain.

As a leading cause of sudden cardiac death in adolescents and young adults, it can be hard to know the severity and what the next steps should be for each individual child’s case. For Dr. Seema Mital, Scientific Co-Lead at the Ted Rogers Centre for Heart Research (TRCHR) and Head of Cardiovascular Research at SickKids, this uncertainty prompted her interest in precision medicine and led to the development of the TRCHR Cardiac Precision Medicine Program. Precision medicine uses the unique genome of a child with heart failure to deliver customized care, prevent complications, and improve outcomes.

For children and teens with HCM, precision medicine is currently being used to determine which patients might benefit from the insertion of an implantable cardioverter defibrillator (ICD) to stop abnormal heartbeats and resume regular heart rhythms in the case of a cardiac emergency. ICDs can be lifesaving for those who need them, but can unfortunately also cause potential serious complications, especially in young children. This makes it challenging for physicians to know how best to proceed for each patient in order to deliver the right outcomes.

Spurred by a desire to help children with HCM and funding from the Ted Rogers Centre for Heart Research, Dr. Mital and her team established an international multi-centre research network called PRecIsion Medicine in CardiomyopathY (PRIMaCY) and developed the PRIMaCY risk prediction tool, which predicts five-year risk of sudden cardiac death from the first time a patient is found to have HCM. PRIMaCY incorporates many different risk factors such as the age of the child, medical, genetic, and family history, and diagnostic measurements to create a holistic and objective risk of sudden death in coming years. The calculator was created and validated using data from many hundreds of HCM patients and is over 70% accurate in distinguishing children at greatest risk, a first in its field.

As of November 2023, PRIMaCY is now available in EPIC, the electronic health records system at SickKids, for physicians to use on all children with HCM, with the goal of reducing sudden cardiac death amongst those most vulnerable. Following successful integration of the PRIMaCY calculator at SickKids, the tool is being prepared for implementation into Epic at several Canadian centres with the help of funding from the Canadian Institutes for Health Research.

In addition to helping prevent devastating outcomes for children with HCM, Dr. Mital’s work was recently promoted in SickKids Foundation’s new campaign, “Heal the Future”. The video (shown below) is based on the true story of a 10-year-old boy, Nathan, who died of a fatal arrhythmia while playing at school four years after having been diagnosed with HCM. In the SickKids campaign, however, the story has a happier ending thanks to precision medicine that helps the healthcare team to identify that he is at high risk of sudden cardiac death and implant an ICD while he is still a child, which activates and eventually saves him as a teenager in the video.

For Dr. Mital, this is a story she hopes will the future of care for children with HCM. “The goal of precision medicine is to make sure we are providing effective therapies and tailoring it to the needs of the child, and this can now be done for children with hypertrophic cardiomyopathies in hospitals across the country”, said Dr. Mital. Precision medicine tools like PRIMaCY have the potential to change the lives of thousands of children diagnosed with HCM in Canada.