Abstract 17673: Sudden Cardiac Death as the First Manifestation of Heart Disease

Abstract

Background: Clinical risk stratification is most challenging in the subgroup of individuals who present with sudden cardiac death (SCD) as the first manifestation of heart disease (SCD-FM) and there is a lack of current era population-based data. Hypothesis: Occurrence of SCD-FM SCD differs by ethnicity and access to health care. Methods: Consecutive out-of-hospital cases of SCD attended by emergency medical services were ascertained prospectively from a large ongoing population-based study in the Southwest US (population ~ 850K, 2015-2022) using an established multi-source ascertainment and adjudication process. A detailed review was conducted of the lifetime clinical record and available autopsy data, for each individual. SCD-FM cases were defined as SCD with no prior heart disease diagnosis. We calculated annual age-standardized incidence of overall SCD and SCD-FM per 100,000 residents using US census data. Ethnicity-stratified incidence of SCD-FM was calculated. Occurrence of all health care visits prior to SCD was evaluated. Results: From a total of 2681 SCD cases (age 71 ± 16, female 35%) age adjusted incidence of SCD was 40[38-41] per 100,000 out of which SCD-FM was 15[14-16] per 100,000 (n=1019 (38%), age 67±18, female 33%). There was no difference in SCD-FM incidence between Hispanic and non-Hispanic residents (15 [13-17] vs 15 [14-17], p=0.84). Individuals younger than 65 yr were more likely to have SCD-FM compared to those older than 65 yr (50% vs 33%, p <0.001). We observed that 91% of SCD-FM had visited healthcare providers and 3% had cardiac evaluations performed. Conclusion: A significantly higher proportion of SCD-FM were age <65 but the proportion of SCD-FM did not differ by ethnicity. The vast majority of SCD-FM (91%) underwent health care visits prior to SCD but cardiac evaluations were rare (3%). These findings highlight the need to discover and develop user-friendly, cost-effective pre-screening methods to reduce SCD-FM in the general population.