The Mayo Clinic report appears as the featured article and editorial topic in the Jan. 16, 2007, issue of the Journal of the American College of Cardiology.

These results identify a tragic situation that could, with increased medical surveillance, potentially be prevented in many cases. To do so requires physicians and families to work astutely together to take a careful multigenerational heart history. Dr. Ackerman says that to identify at-risk relatives, all immediate family members of the person who died inexplicably must undergo comprehensive cardiac evaluation that includes, at a minimum, an electrocardiogram and an exercise stress test as initial screens for LQTS and CPVT.

If evidence of heart problems is found, family members need to act immediately by getting screened for the lethal mutations, and treated, if necessary, he says.

"Families who have lost a loved one to sudden unexplained death should now know that they can do more if the coroner or medical examiner is unable to provide an explanation for their loved one's sudden and unexplained death," Dr. Ackerman says. "Postmortem genetic testing could be performed on the victim of sudden death in search of the cause. Now, one-third of the time, we can find the cause."

To prevent these kinds of sudden unexplained deaths, family members and physicians must be alert to -- and act on -- warning signs of a heart condition. Although all deaths in the study were officially categorized as unexplained, the medical histories showed that nearly half of those with the lethal mutations had experienced a warning sign prior to death.

Warning signs of possible mutation-linked heart abnormality include:

• sudden fainting or a sudden seizure.

• evidence of unexplained death in the family history, such as a moto
  '"/>