It's estimated that 450,000 Americans die from sudden heart conditions, and in about one in ten cases, the cause is unexplained even when an autopsy is conducted. Scientists have now found that about 20 percent of people with sudden cardiac death carry rare, small changes in the sequence of certain genes. These rare genetic variants are thought to raise the risk of cardiac death, and the researchers suggested that some of these deaths could potentially be preventable if the variant is identified. The findings have been reported in JAMA Cardiology.
"Genetic screening isn't routinely used in cardiology, and far too many patients still die suddenly from a heart condition without having any previously established risk factors. We need to do more for them," said study corresponding author Aloke Finn, M.D., a Clinical Associate Professor of Medicine at the University of Maryland School of Medicine (UMSOM).
In this work, the study team sequenced genes from 413 patients that died at an average age of 41 due to sudden heart failure without an identified cause. About half of these patients were Black, and about two-thirds were men. The research suggested that 18 percent of these patients also carried gene variations that have been linked to heart failure or life-threatening arrhythmia. The people carrying these genetic variants had not shown any indication of heart failure; they had no significant blockages in coronary arteries and their hearts had a normal appearance.
"What we found opens the door and asks some important questions," Finn said. "Should we be doing routine genetic screening in those who have a family history of unexplained sudden cardiac death?"
Genetic screening that looks for genetic variants that raise a person's risk of sudden cardiac death may save lives, but only if patients are able to use that genetic data to change health outcomes. That information could also just make people stressed out about the risk if there is no clear way to mitigate it. Right now, there are no guidelines for how to advise or treat patients that do not have clinical symptoms of heart disease, like blockages or abnormalities that can be seen on scans.
More work will be needed to reveal potential treatments, and it's not known how standard advice to eat healthy foods and get enough exercise might work in these cases.
"This is a fascinating study that provides important new insights into devastating deaths due to unexplained cardiac abnormalities," said E. Albert Reece, M.D., Ph.D., M.B.A., Dean of UMSOM among other appointments. "It certainly makes the case for more research to address this urgent health need and save lives in the future."