Sudden cardiac death (SCD) in young people is a rare but devastating event for families and communities. Ireland has previously had no measure of the incidence of SCD in young people. We report the incidence and causes of SCD in persons <35 years of age. We undertook a retrospective study of SCD between 2005 and 2007 in persons aged 15-35 years in the Republic of Ireland. We identified potential cases of out of hospital SCD through the Central Statistics Office (CSO) death certificate records. Autopsy, toxicology, and inquest reports were then obtained and analysed by an expert panel who adjudicated on the cause of death. A total of 342 potential SCD cases were identified through the CSO. Fifty were younger than 15 years of age, and 86 had either incomplete or unavailable post-mortem reports. Of 206 full reports obtained, 116 were adjudicated as cases of SCD. Cases were predominantly male (75%), with a mean age of 25.8 years (standard deviation 6.3). The incidence of SCD in this age range was 2.85 per 100,000 person-years (4.36 for males and 1.30 for females) and the incidence of sudden arrhythmic death syndrome (SADS) was 0.76 per 100,000 person-years. The commonest causes were SADS, 26.7% (31 of 116), followed by coronary artery disease, 20.7% (24 of 116), hypertrophic cardiomyopathy (HCM), 14.7% (17 of 116), and idiopathic left ventricular hypertrophy not fulfilling criteria for HCM, 10.3% (12 of 116). The incidence of SCD in the young in Ireland was 4.96 (95% CI 3.06, 6.4) for males and 1.3 (95% CI 0.62, 2.56) for females per 100 000 person-years. Sudden arrhythmic death syndrome was the commonest cause of SCD in the young, and the incidence of SADS was more than five times that in official reports of the Irish CSO.
