Temporal trends of left ventricular function preceding sudden cardiac death.

BACKGROUND: Severely reduced left ventricular ejection fraction (LVEF≤35%) increases the risk of SCD and is considered the most important indication for medical and device therapies used to prevent SCD. Spectrum of LVEF among SCD subjects in the modern era remains unclear. OBJECTIVE: We evaluated temporal changes of left ventricular ejection fraction (LVEF) during two decades among SCD victims with both ischemic and nonischemic etiologies. METHODS: The Fingesture study is a population-based study of SCD that comprises 5,869 consecutive autopsy-verified SCD victims from Northern Finland between 1998 and 2017. Quantitatively assessed LVEF was acquired from electronic health records (EHR). In all cases, echocardiography was unrelated to the SCD event. The study period was divided into 5-year quartiles to study temporal trends. RESULTS: Pre-SCD LVEF was available among 716 SCD victims. The prevalence of severely reduced LVEF was 15.4% (110 subjects) during the entire study period and significantly decreased over the study period quartiles to one third from baseline (30.6% during 1998-2002, 20.0% during 2003-2007, 13.5% during 2008-2012, and 10.6% during 2013-2017 (p<0.001, unadjusted β=-5.6% per every 5 years, 95% CI -8.3% to -2.9%). Overall incidence of SCDs per capita and those with echocardiography remained essentially the same during last 15 years. CONCLUSION: The proportion of SCD cases with LVEF ≤35% has decreased significantly in recent decades. Only a minority of modern-day SCD victims undergoing echocardiography are identified as high-risk individuals for SCD according to LVEF. Individualized risk assessment beyond LVEF measurement is needed to assess risk for SCD.