Autopsy findings and cardiac arrest rhythms in young obese patients with sudden cardiac death of uncertain etiology

Abstract

Abstract Background Obesity is associated with an increased risk of sudden cardiac death (SCD) which can be particularly devastating in young adults. In a significant proportion of SCD cases in the young, a specific cause cannot be identified. Purpose The aim of this retrospective analysis was to describe the demographics, pathological changes and cardiac arrest rhythm in young obese individuals with SCD of otherwise unknown etiology. Methods Between July 2000 and December 2018, the National Coronial Information System (NCIS) identified cases of young obese (body mass index ≥ 30) individuals with SCD between 17-35 years of age (SCD-obesity). Autopsy reports of individuals with SCD where known causes had been excluded were compared to 2 matched control cohorts of death due to motor vehicle accidents (MVA) (first group matched for age, sex, height and weight (MVA-BMI-matched) and second group matched for age and sex (MVA-age-matched)). Additionally, electrocardiographic rhythms at cardiac arrest were obtained through state-wide ambulance services for SCD-obesity individuals. Results We identified 409 cases of SCD in young obese individuals, of which 94 cases met the inclusion criteria (figure 1). Mean age was 28.44±5.6 years (range 17-35). SCD-obesity individuals were commonly males (71%). SCD-obesity individuals had significantly higher cardiac masses (521g vs 417g, p<0.001) compared to the MVA-BMI-matched cohort. SCD-obesity individuals also had significantly increased left ventricular wall thickness (15.6mm vs 13.5mm, p<0.001) and increased rates of left ventricular fibrosis (73% vs 52%, p=0.045) compared to the MVA-BMI-matched cohort. ECG rhythm strips were available for 71 (72%) SCD-obesity cases, of which 16 (23%) were unwitnessed. Asystole was noted on 7 (46.67%) of witnessed cases, and 6 (40%) had a ventricular tachycardia or fibrillation (figure 2). Conclusions SCD-obesity individuals had increased cardiac organ masses, left ventricular wall thickness and cardiac fibrosis. The cardiac arrest rhythm recorded in witnessed cases were predominantly asystole and ventricular arrythmia. Future studies are needed to determine the pathological mechanisms explaining these abnormalities in young obese sufferers of SCD.Figure 1:Case identificationFigure 2:Results