Efforts to prevent sudden cardiac death (SCD) have primarily focused on athletes, with limited data in the broader young population. This large screening study published in the Journal of the American College of Cardiology assessed diagnostic yield, subsequent cardiac diagnoses, and incidence of sudden cardiac arrest (SCA) and SCD following a single cardiac evaluation in individuals aged 14-35 years.

Between 2008 and 2018, 104,369 consecutive individuals (62% male, 89% White, 9% athletes) underwent screening with a questionnaire, electrocardiogram (ECG), and selective echocardiography. All participants were evaluated by a cardiologist, with secondary testing recommended when appropriate. Outcomes were obtained through national databases and follow-up questionnaires.

Of those screened, 2,619 (2.5%) were referred for secondary evaluation: 937 (0.9%) for symptoms or family history, 1,361 (1.3%) for abnormal ECG, and 321 (0.3%) for both. Screening identified 280 (0.3%) individuals with conditions associated with SCA/SCD; 115 (41%) received risk-modifying interventions, including 10 prophylactic implantable cardioverter defibrillators and 2 cardiac transplants. 

Over a mean follow-up of 6.0±2.5 years, 86 (0.08%) additional individuals were diagnosed with SCA/SCD-associated conditions, including 35 presenting with SCA (n=15) or SCD (n=20). The incidence of SCA/SCD was 5.6 per 100,000 person-years. The median age at event presentation was 23.8 years (IQR: 10.5), and events occurred a median of 3.6 years (range: 0.2-11.7) after screening. The sensitivity of the ECG and questionnaire for detecting conditions related to SCA/SCD was 75.4% and 32.5%, respectively.

Screening detected SCA/SCD-associated conditions in 0.3% of individuals aged 14 to 35 years, and 41% of those diagnosed underwent risk-modifying procedures beyond lifestyle modification or pharmacotherapy. During approximately six years of follow-up, 0.08% of participants who were initially cleared were later diagnosed with relevant cardiac conditions or experienced SCA/SCD events. The observed incidence rate was 5.6 per 100,000 person-years. These findings highlight the occurrence of delayed clinical presentation following a single evaluation.