A significant proportion of sudden cardiac deaths that remain unexplained after autopsy and blood tests may be due to inherited heart disease, according to findings reported in the November 1st issue of the Lancet. The British researchers suggest that family members of people who have an unexplained sudden cardiac death should be evaluated themselves.

Roughly 1 in 10,000 people in England die of sudden cardiac death. Previous research had indicated that around 4 percent of these deaths are unexplained, with postmortem results indicating normal heart function before death. The researchers tested the hypothesis that at least some of these deaths represent inherited heart disease by evaluating the first-degree relatives (siblings, children, parents) of 32 people who had such a death (average age at death, 30 years). Of the 32 families evaluated, 7 (22 percent) were found to have inherited electrophysiological or myocardial disease.

William McKenna, MD, senior study author, commented "In those families diagnosed with inherited heart disease, there had been significantly more sudden cardiac deaths among relatives than in the other families. If these sudden deaths had prompted family screening, particularly of relatives with symptoms, some of those deaths may have been prevented."

In an accompanying Commentary, Adriana Lee, MD, and Michael J Ackerman, MD, concluded that "It now seems reasonable to suggest a screening 12-lead electrocardiogram for the assessment of first-degree relatives of a confirmed sudden unexplained death. However, it will often take more than just an electrocardiogram to unveil the cause of death. Further studies are needed to establish the most cost-effective standard of care for the post-death evaluation of sudden unexplained death in those left behind...With the cause in hand, physicians can allay the greatest fear, the unknown, for those whose loved one died suddenly, unexpectedly, and without explanation, and be better equipped to guide those that are left behind with informed counseling, thorough and appropriate evaluation, proper treatment, and hopefully prevention of another loss."