Sudden cardiac death, with no warning or medical explanation, has become one of the biggest mysteries of modern medicine.
In a landmark new study published in the New England Journal of Medicine, medical researchers at The Royal Melbourne Hospital have helped shed some light on who, when and where sudden cardiac death (SCD) in young people occurs.
The study, "A Prospective, Population-Based Study of Sudden Cardiac Death in the Young", led by Professor Chris Semsarian from Sydney University, looked at more than 490 sudden cardiac deaths in otherwise healthy Australian and New Zealanders aged from 1-35 between 2010 to 2012.
Together, they found that 198 deaths could not be explained – that’s 40 percent of young people, suddenly dying, leaving their families and doctors at a loss to understand why it happened.
Professor Ingrid Winship, Executive Director of Research and Director of Genetic Medicine at The Royal Melbourne Hospital, believes the research provides great insight into SCD.
“We know that one to four young Australians, aged between one and 35, die each week from sudden cardiac arrest,” says Professor Winship.
More than 65 per cent of these sudden deaths occurred between 6pm and 6am, when the person was asleep or taking part in low energy activities. 72 per cent of those who died were male, while ages 16 to 20 years of age had the highest incidence of unexplained sudden cardiac death.
According to Professor Winship, the study has helped link the incidences of SCD with mutations in genes predisposing to cardiac disorders.
“Of the 113 cases of unexplained sudden cardiac death, a clinically relevant cardiac gene mutation was identified in 31 when genetic testing was performed. Clinical investigations in family members, identified a diagnosis of an inherited cardiovascular disease in 13 percent of the families in which an unexplained death occurred,” Professor Winship says.
“Most of these conditions had a 50/50 chance of being passed onto the next generation. If you know why the young person died suddenly, you can test their family members for the specific genetic mutation. Cardiologists are then able to manage that risk.”
For families who are found to have a genetic condition that puts them at risk of SCD, there are medical interventions such as implantable cardioverter defibrillators to prevent sudden death from occurring.
The cardiac genetic clinic at The RMH is a leader in this field, providing a multidisciplinary approach to a wide range of inherited cardiac diseases.
The clinic, managed by Ms Tina Thompson, has strong links with the Victorian Institute of Forensic Medicine, together the two services facilitates the investigation of the genetic condition underpinning of sudden cardiac death.
Associate Professor Paul James, Head of Adult Clinical Genetics at The RMH, believes that the great importance of this work lies in the opportunity it opens to prevent young people from dying of SCD in the future.
“It very often seems that sudden cardiac death is unpredictable and unpreventable but this study gives us hope that it doesn’t have to be the case,” A/Professor James says.
“The insight that we are getting is critical for better measures to identify young people at risk and ultimately save more families from this heartbreak.”