Call to Cardiac Screen All Family Members of Sudden-Death Victims

June 03, 2009

June 3, 2009 (Vienna, Austria) — In the largest study of its kind to date, researchers at a specialized cardiogenetics center in the Netherlands have screened the close families of sudden-unexplained-death (SUD) victims and found that a third of them are affected by inherited heart disease [1]. Dr Christian Van der Werf (Academic Medical Center, Amsterdam, the Netherlands) reported the findings at the European Society of Human Genetics meeting in Vienna earlier this week.

Van der Werf, a research fellow in the department of cardiogenetics, told heartwire that the majority of such relatives are not currently being referred for screening: "We estimate that only 10% of SUD families are being examined for inherited heart conditions. The scale of heart disease that we found in such families underlines the necessity for general practitioners to refer first-degree relatives of SUD victims to a specialized cardiogenetics department as soon as possible. By taking these measures we can save lives and avoid further distress for families who have already suffered enough."

In such centers, "clinical geneticists, cardiologists, and psychosocial workers cooperate [and] specialize in inherited heart diseases and their clinical and psychosocial implications and can provide a better quality of care," he explains. However, he acknowledges that such specialized centers are not widely available and in lieu of this kind of service, he says cardiologists in general should receive more education with regard to inherited heart disease.

Tailored Screening Identifies Best Management for Individual Patients

The researchers say that when an individual aged one through 50 years dies suddenly, autopsy reveals an inheritable heart disease in the majority of the victims. But Van der Werf told heartwire that, in the Netherlands, autopsy is not mandatory in SUD victims, whereas in other countries, such as the UK, it is. However, even if an autopsy is performed, "the pathologist usually does not specialize in the heart," he noted

Van der Werf and colleagues looked at the outcome of first-degree-relative screening in 127 families who had suffered a SUD where there had been no autopsy (53.8%) or the autopsy did not reveal a cause of death. The average age at death of the SUD victims was 29.8 years old and, per family, a mean of 2.5 first-degree relatives were examined.

"We all worked together to see the families, taking their personal history and ECG," Van der Werf explained, adding that, in some cases, a second cardiac autopsy of the SUD victim was undertaken if tissue had been stored and was available. He stressed that the strategy differs for each family, depending on what is discovered. "If there is a big suspicion of a certain inherited cardiac disease, the last step of our targeted approach will be genetic screening."

A probable diagnosis was made in 36 of the families (31.3%), with primary arrhythmia syndromes being the most important causes: electrical catecholaminergic polymorphic ventricular tachycardia and long-QT syndrome were the most common diagnoses, affecting eight and seven families, respectively.

Using the example of long-QT syndrome, Van der Werf explained how genetic testing can help identify the specific mutation responsible, which can then help in management of the affected patients.

"Some types [of long-QT syndrome] can be managed with medication, eg, beta blockers, whereas in other subtypes medication is not effective. Some individuals receive lifestyle advice only, such as refraining from competitive sports, and others receive [implantable cardioverter defibrillators] ICDs."

Referral to Specialist Centers Will Help Identify More Affected Families

Van der Werf says the new findings add to two smaller UK studies in the field, and this is the second report from the registry of families at his center. The team is continuing to follow other family members of SUD victims to report the yield of family screening.

They are also trying to encourage general practitioners and other involved physicians to request autopsy and DNA storage for SUD patients "and to refer relatives to a cardiogenetics department after a case of sudden death at young age. We hope this will lead to identification of more families at risk of sudden cardiac death, in which preventive measures then can be taken."

He says there are eight such specialist cardiogenetics centers in the Netherlands and that a few other countries have well-developed networks, "but the field of cardiogenetics is not really developed in the US," he notes, in terms of the availability of such integrated centers.

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