Why screen for inherited heart conditions?
Inherited heart conditions have been in the news recently after a TV advert by The British Heart Foundation started airing on national TV. The BHF hope this will prompt people to ask questions to find out more, raising awareness and encouraging more people to donate towards research funds. Dr Amanda Varnava, Consultant Cardiologist at The Physicians' Clinic and Clinical Lead in Inherited Cardiac Conditions within the Imperial College Healthcare NHS Trust has been in demand for media interviews and quotes. Here she explains who should think carefully about screening.
The British Heart Foundation TV ad
During her interview with Sky News, Dr Varnava commented that people generally do not realise just how common these disorders are. "Around one in 300 people have an inherited heart condition. Worryingly, 15% of those who suffer sudden death, do so as a result of harbouring one of these conditions, often without any previous diagnosis. Sadly, at least 12 young and seemingly fit people die each week in the UK as a result of an undiagnosed inherited heart problem," she says.
Types of inherited heart condition
Three main types of inherited heart condition are known. The first involves a genetic mutation that alters the way electrical signals pass through the heart, leading to abnormal heart rhythms. The most common of these are:
- Long QT syndrome (LQTS)
- Brugada syndrome
- Catecholaminergic polymorphic ventricular tachycardia (CPVT)
- Progressive cardiac conduction defect (PCCD)
In the second, those affected have a greater risk of abnormality of their heart muscle, a process termed cardiomyopathy. The three most common disorders are:
- Hypertrophic cardiomyopathy
- Arrhythmogenic right ventricular cardiomyopathy
- Dilated cardiomyopathy
Finally, it is also possible for a genetic mutation to cause very high cholesterol, resulting in:
- Familial hypercholestrolaemia
"The medical names for these disorders are long and complex but the names don't matter. The most important thing is that people are aware that such disorders exist and that they are dominant. This means they can be passed on through the generations and a parent who is affected has a 50% chance of passing the heart problem on to their child," explains Dr Varnava.
Screening for inherited heart conditions
Dr Varnava regularly screens two groups of people:
- Young athletes: it is becoming more common for young athletes to receive cardiac screening for inherited disorders in the UK. "It is commonplace in Italy and the USA, and the introduction of routine screening has reduced the rate of sudden death in young athletes by around 90%".
- Families affected by a sudden death: an important part of Dr Varnava's work is with families that have lost a teenager or young adult to a sudden cardiac death. "We often find a genetic cause and it is then important to assess other members of the family - parents, siblings, children - to determine their level of risk and to mitigate it."
Screening is important as identifying a genetic problem means that your risk of a serious cardiac event, including sudden death, can be properly assessed. "Not all people who have a genetic heart condition will show any symptoms or die suddenly - it is possible to live into old age and never know that you carry the disorder. However, someone who is identified as having a potentially high risk of sudden death can receive advice, preventive treatment and monitoring to reduce that risk," says Dr Varnava. Dr Varnava has recently worked with a family who very tragically lost a son in his 20s to sudden death "They have done a lot to raise funds for our research group and we hope to make substantial progress in the next few years."