Family-based cardiac screening in relatives of victims of sudden arrhythmic death syndrome.

AIMS: Sudden arrhythmic death syndrome (SADS) occurs when a person suffers a sudden, unexpected death, with no cause found at postmortem examination. We aimed to describe the cardiac screening outcomes in a population of relatives of SADS victims

METHODS AND RESULTS: Prospective and retrospective cohort study of consecutive families attending the Family Heart Screening clinic at the Mater Misericordiae Hospital in Dublin, Ireland, from January 2007 to September 2011. Family members of SADS victims underwent a standard screening protocol. Adjunct clinical and postmortem information was sought on the proband. Families who had an existing diagnosis, or where the proband had epilepsy, were excluded. Of 115 families identified, 73 were found to fit inclusion criteria and were retained for analysis, with data available on 262 relatives. Over half of the screened family members were female, and the mean age was 38.6 years (standard deviation 15.6). In 22 of 73 families (30%), and 36 of 262 family members (13.7%), a potentially inheritable cause of SADS was detected. Of the population screened, 32 patients (12.2%) were treated with medication, and 5 (1.9%) have received implantable cardiac defibrillators. Of the five families with long QT syndrome (LQTS) who had a pathogenic gene mutation identified, three carried two such mutations.

CONCLUSION: In keeping with international estimates, 30% of families of SADS victims were found to have a potentially inherited cardiac disease. The most common positive finding was LQTS. Advances in postmortem standards and genetic studies may assist in achieving more diagnoses in these families.