Genetic Tests Check Risk for Sudden Death

Nov. 16, 2009 (Orlando, Fla.) -- If you have a relative who suffered sudden unexplained death, postmortem genetic testing is a cost-effective way of identifying mutations that may place you and other surviving family members at increased risk for potentially fatal heart rhythm disturbances, a new study suggests.

"Postmortem gene testing may be a better way to determine risk to relatives than traditional comprehensive cardiac testing of first-degree relatives," says researcher Michael J. Ackerman, MD, PhD, of the Mayo Clinic in Rochester, Minn.

Nearly 300,000 Americans a year suffer sudden cardiac death, in which a person dies within minutes after an abrupt loss of heart function.

Genetic defects explain up to 25% to 30% of these cases, Ackerman says.  But rather than provide genetic testing to the deceased individual, the recommended approach is to offer comprehensive cardiac testing to first-degree relatives, he says.

For the study, Ackerman and colleagues performed postmortem testing for two genetic heart rhythm disorders associated with sudden cardiac death on 146 people who had suffered sudden unexplained deaths. Results showed that 40 patients (27%) had one of the two mutations known to cause sudden cardiac death.

The researchers then performed further testing on 160 relatives of victims who tested positive for mutations. The tests included genetic screening and either treadmill stress tests or electrocardiograms. 

The total cost of the gene-directed exams: $6.78 million.

Then, the researchers performed the currently recommended comprehensive cardiac testing on all relatives of the sudden unexplained death victims, regardless of their mutation status. The cost exceeded $7.7 million.

“Use of a [genetic] autopsy to direct further testing would save almost $1 million dollars," Ackerman says.

A major obstacle to genetic testing is that insurance companies typically don't cover the cost, while they do pay for the more expensive comprehensive cardiac testing for all family members, he says.

Johns Hopkins cardiologist Gordon Tomaselli, MD, who moderated a news briefing on the findings, tells WebMD that he hopes data like these will propel more insurance companies to pay for the gene testing.

The study was reported at the annual meeting of the American Heart Association.