Researchers looked at 470 victims of sudden cardiac death (SCD) between the ages of 1 and 35, and followed their first and second-degree relatives for up to 11 years. The results show that the relatives who were younger than 35 had three times the risk of cardiovascular disease, six times the risk of ischaemic heart disease, and more than 10 times the risk of cardiomyopathies and ventricular arrhythmias. The risks were even higher for first-degree relatives of SCD victims.
"The most interesting findings were that risk of CVD overall was increased no matter what subgroups of SCD victims and relatives we examined, and that young (under 35 years) first-degree relatives overall had a four-fold increase in risk of any CVD, and nearly 20-fold increases in risk of cardiomyopathy and ventricular arrhythmia," said Dr. Mattis Ranthe, lead author of the study and a research fellow at the Department of Epidemiology Research at Statens Serum Institut. "Finding a risk factor associated with a four-fold or greater increase in CVD risk is rare!"
Ranthe and his colleagues suggest that that autopsies should always be performed in the case of SCD in young people. Also, they recommend that close relatives of the victims be screened to detect any conditions that could benefit from preventive treatment.
"Our results show SCD, or the underlying heart problems, has a large hereditary component, and that relatives, particularly young, first-degree relatives, are at much greater risk of developing heart conditions compared with the general population," said Ranthe. "Family members of young SCD victims should be offered comprehensive and systematic screening, with the focus on the youngest and nearest relatives.
"Most of the cardiovascular diseases leading to sudden cardiac death are treatable, if diagnosed in time, before a fatal event. Our results reinforce the concept of screening as a rational 'tool' to identify such cardiovascular diseases in family members at risk, and thereby possibly prevent future sudden cardiac deaths. However, our findings do not suggest blanket screening of, for example, asymptomatic second-degree relatives of SCD victims, although cascade screening might trigger screening of more distant relatives after a CVD finding in a first-degree relative."