Febrile seizures prior to sudden cardiac death: a Danish nationwide study.

Aims: Febrile seizure (FS) is a common disorder affecting 2-5% of children up to 5 years of age. The aim of this study was to determine whether FS in early childhood are over-represented in young adults dying from sudden cardiac death (SCD). Methods and results: We included all deaths (n = 4595) nationwide and through review of all death certificates, we identified 245 SCD in Danes aged 1-30 years in 2000-09. Through the usage of nationwide registries, we identified all persons admitted with first FS among SCD cases (14/245; 5.7%) and in the corresponding living Danish population (71 027/2 369 785; 3.0%) and also in victims of transport accidents (26/917; 2.8%). The frequency of FS among SCD cases was significantly increased by an odds ratio of 1.96 [95% confidence interval (CI) 1.14-3.36; P = 0.021] compared with the living Danish population and with an odds ratio of 2.08 (95% CI 1.07-4.04; P = 0.046) compared with transport accident victims. SCD cases did not differ statistically in birth year (P = 0.272), age at SCD (P = 0.667) or prior medical conditions, except for epilepsy (P < 0.001), when comparing SCD with and without prior FS. The most common cause of death in autopsied SCD cases with FS was sudden arrhythmic death syndrome (5/8; 62.5%). Conclusion: In conclusion, this study demonstrates a significantly two-fold increase in the frequency of FS prior to death in young SCD cases compared with the two control groups, suggesting that FS could potentially contribute in a risk stratification model for SCD and warrant further studies.