P5026Diagnostic yield in victims of sudden cardiac death and their relatives

Background International guidelines recommend screening of relatives in families with sudden cardiac death (SCD) if the cause of death is suspected to be an inheritable cardiac disease. The inheritable cardiac diagnosis may either have been known before the death, established at the autopsy or identified through screening of relatives. Purpose To provide an estimate of the diagnostic yield of inherited cardiac disease in SCD victims. Methods In an observational study, we included all families consecutively referred to our tertiary unit for inheritable cardiac diseases in the period from 2005 to 2018 due to SCD. Families with SCD victims under 1 year of age were excluded. In total, 697 relatives from 305 families were included and all relatives underwent a standard screening protocol, which included clinical and genetic work-up. Premortem medical records and postmortem findings on the SCD victim were ascertained whenever possible. Results A definite inheritable cardiac disease was identified in 113 out of 305 SCD families prior to family screening. The diagnosis was established through autopsy findings (n=89), genetic analysis (n=3) or was established prior to death (n=21). In the remaining 192 families with no or a borderline diagnosis only, screening of the relatives yielded a diagnosis in additional 28 families (15%). On a family-basis, a total of 141 out of 305 families (46%) were diagnosed. Seventy-seven (11%) out of the 697 screened relatives received either a phenotype-positive and/or genotype-positive inheritable diagnosis and 70 (10%) relatives received a borderline diagnosis. The most common diagnoses in the relatives were ARVC (n=17) followed by DCM (n=10) (see figure). Conclusion Almost half of SCD families were diagnosed with an inheritable cardiac disease of which one fifth of the families were diagnosed as a result of family screening. In 11% of the screened relatives a probable inheritable diagnosis was identified.