Spotting and preventing sudden death risk in children with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an inherited heart condition that causes the heart muscle to become thicker. As well as making it more difficult for the heart to pump blood around the body, it can lead to life-threatening abnormal heart rhythms and sudden cardiac arrest (where your heart stops beating).

These cardiac arrests can be prevented with an implantable cardioverter defibrillator (ICD) – a device fitted in the chest which sends electrical pulses to help regulate abnormal, potentially life-threatening, heart rhythms. So it’s important to know which people with HCM are at high risk of a cardiac arrest, so they can have a potentially life-saving ICD.

Finding children at risk of sudden death

In 2014, a scoring system was developed to predict which people with HCM are at high risk of a cardiac arrest. But this scoring system was not designed for people younger than 16.

So in 2019, BHF Clinical Research Training Fellow Dr Gabrielle Norrish and Dr Juan Pablo Kaski at University College London and Great Ormond Street Hospital led a study aiming to improve risk prediction for children with HCM. Using anonymised medical records of over 1000 children with HCM around the world, they identified characteristics which were associated with a higher risk of sudden death in children compared to adults. For example, they found that experiencing unexplained fainting is linked to an increased risk of sudden cardiac death in children, just as it is in adults. But changes in some heart measurements that can be seen on an echocardiogram and having a family history of sudden cardiac death can help predict risk in adults but not in children – meaning that the ‘adult’ tool can miss some children at high risk.

In 2019, they used these findings to develop a tool to help doctors to better identify children with HCM who may need an ICD. While further research is needed to validate and further refine this tool, it’s hoped that in the future this research can be applied to help ensure ICDs are targeted at children with HCM who most need one. In addition, by working out which children with HCM are at low risk, this tool could help to reassure those children and their families.

First published 1st June 2021