Abstract 19166: Activity Level and Causes of Sudden Death: From the San Francisco Postmortem Systematic Investigation of Sudden Cardiac Death (POST SCD) Study

Abstract

Introduction: Level of activity has a reported association with sudden death, but cardiac causes are presumed by convention. We investigated association between activity level and causes of presumed SCD (pSCD) in the San Francisco POstmortem Systematic InvesTigation of Sudden Cardiac Death (POST SCD) Study. Methods: POST SCD is a prospective cohort study using autopsy, clinical records, and toxicology to adjudicate arrhythmic (potentially rescuable with implantable defibrillator) or non-arrhythmic (e.g., tamponade, overdose) causes among pSCDs (WHO defined) 18-90 years in San Francisco. We included all incident cases from 2/1/11-3/1/14 (n=525) and incident cases approximately every 3rd day from 3/1/14-12/31/21 (n=358). Activity level at time of pSCD was determined by forensic investigator reports. For unwitnessed deaths, activity level was inferred based on time of arrest and location found. Activity level was classified as: sleep, recently awoke (&lt10 min before death), awake with no activity (e.g., sitting), mild/moderate (e.g., bathing, feeding, walking), and rigorous (e.g., strenuous activity, sexual activity). Results: Of the total 883 pSCDs (mean 60 years, 73% male), 247 (28%) were sleeping, and 516 (58%) were awake at time of event. Cases with unclear circumstances (n=120, 14%) were excluded from analysis. Sleep was associated with non-cardiac cause of death (p=.01), specifically SUDEP (p=.02) and occult overdose (p&lt.001). Wakefulness was associated with SAD (p=0.005), pulmonary embolism (p=.007), and vascular damage (p=.004) (Table). Nearly all cases engaging in rigorous activity at time of death (n=32) were SADs (31/32, 97%) and male (29/32, 91%). Conclusions: Most sudden deaths in this 11-year countywide postmortem study occurred during wakefulness. Sleep was associated with non-arrhythmic cause (specifically SUDEP and occult overdose), while wakefulness and rigorous activity were associated with arrhythmic cause of sudden death.