Symptoms, ecg-changes and family history of cardiac disease precedes sudden cardiac death in hypertrophic cardiomyopathy - A nationwide study among the young in Sweden 2000-2010

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND - Hypertrophic cardiomyopathy (HCM) is a genetic cardiovascular disease associated with increased morbidity and mortality, and may be the most common cause of sudden cardiac death (SCD) in the young. PURPOSE - To characterize detailed family history, symptoms, hospital utilization and ECG-changes before SCD due to HCM. METHODS - Cases were identified using the SUDDY.se cohort database, a nationwide comprehensive cohort consisting of 903 individuals aged 0-35, who suffered from SCD, in Sweden 2000-2010. The database also includes five population-based controls from Statistics Sweden, per case, together with parents of cases and controls (n = 15 633). Our database encompasses data from mandatory national registries together with the autopsy reports, medical records, ECGs (also military conscript), and detailed family history from an interview-based questionnaire (relatives, post-mortem). All individuals with autopsy findings or clinical diagnosis pre-mortem consistent with HCM were included in the study. RESULTS- HCM was the cause of death in 38 cases, (38/903, 4,2%); 31 male and 7 female, mean age 22 years. The majority of cases (27/38= 71%) presented with possible cardiac symptoms (Including chest pain (10/27 = 26,3%), syncope 22%, palpitations 37%), prior to death. A majority,69%, were attending hospital or outpatient care (vs 21% in controls) within 180 days prior to death. The majority of cases (68%) died during recreational activity (n = 14; 37%) or exercise/competitive sports (n = 12; 31%). In seven of the 12 sports-related cases, death occurred during competitive sports, with basketball being the most common sport (43%). Almost half of the cases had a known cardiac disorder prior to death (15/38, 39%), where HCM was diagnosed premortem in nine cases (9/38, 24%). In addition, we found that over half of the SCD-cases with HCM, presented with an abnormal ECG (n = 22; 58%) prior to death, 12 (55%) in the absence of symptoms. Half of the cases (n = 19) had a positive family history (1st-3rd generation) for heart disease. CONCLUSION(S) - In this nation-wide study of SCD due to HCM, more than 2/3 of cases, had experienced cardiac symptoms prior death, and a high percentage was seeking hospital or outpatient care, in the last 6 months prior to death. A positive family history for cardiac disease, as well as ECG-abnormalities, was seen in half of the cases, respectively. These findings demonstrate that clinical screening including ECG and family history is of great importance in identifying individuals at risk of SCD due to HCM. Such screening, as well as increased attention to possible cardiac symptoms in the young, should possibly be expanded beyond professional athletes to aid prevention of SCD in the young population with HCM.