Refining the World Health Organization Definition: Predicting Autopsy-Defined Sudden Arrhythmic Deaths Among Presumed Sudden Cardiac Deaths in the POST SCD Study

Circ Arrhythm Electrophysiol. 2019 Jul;12(7):e007171. doi: 10.1161/CIRCEP.119.007171. Epub 2019 Jun 28.


Background: Conventional definitions of sudden cardiac death (SCD) presume cardiac cause. We studied the World Health Organization-defined SCDs autopsied in the POST SCD study (Postmortem Systematic Investigation of SCD) to determine whether premortem characteristics could identify autopsy-defined sudden arrhythmic death (SAD) among presumed SCDs.

Methods: Between January 2, 2011, and January 4, 2016, we prospectively identified all 615 World Health Organization-defined SCDs (144 witnessed) 18 to 90 years in San Francisco County for medical record review and autopsy via medical examiner surveillance. Autopsy-defined SADs had no extracardiac or acute heart failure cause of death. We used 2 nested sets of premortem predictors-an emergency medical system set and a comprehensive set adding medical record data-to develop Least Absolute Selection and Shrinkage Operator models of SAD among witnessed and unwitnessed cohorts.

Results: Of 615 presumed SCDs, 348 (57%) were autopsy-defined SAD. For witnessed cases, the emergency medical system model (area under the receiver operator curve 0.75 [0.67-0.82]) included presenting rhythm of ventricular tachycardia/fibrillation and pulseless electrical activity, while the comprehensive (area under the receiver operator curve 0.78 [0.70-0.84]) added depression. If only ventricular tachycardia/fibrillation witnessed cases (n=48) were classified as SAD, sensitivity was 0.46 (0.36-0.57), and specificity was 0.90 (0.79-0.97). For unwitnessed cases, the emergency medical system model (area under the receiver operator curve 0.68 [0.64-0.73]) included black race, male sex, age, and time since last seen normal, while the comprehensive (area under the receiver operator curve 0.75 [0.71-0.79]) added use of β-blockers, antidepressants, QT-prolonging drugs, opiates, illicit drugs, and dyslipidemia. If only unwitnessed cases <1 hour (n=59) were classified as SAD, sensitivity was 0.18 (0.13-0.22) and specificity was 0.95 (0.90-0.97).

Conclusions: Our models identify premortem characteristics that can better specify autopsy-defined SAD among presumed SCDs and suggest the World Health Organization definition can be improved by restricting witnessed SCDs to ventricular tachycardia/fibrillation or nonpulseless electrical activity rhythms and unwitnessed cases to <1 hour since last normal, at the cost of sensitivity.

Keywords: arrhythmias; autopsy; sudden cardiac death; ventricular fibrillation.

Publication types

  • Research Support, N.I.H., Extramural
  • Validation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Autopsy
  • Cause of Death
  • Death, Sudden, Cardiac / epidemiology*
  • Echocardiography
  • Electrocardiography
  • Female
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Reproducibility of Results
  • Risk Assessment
  • Risk Factors
  • San Francisco / epidemiology
  • Tachycardia, Ventricular / classification
  • Tachycardia, Ventricular / diagnosis
  • Tachycardia, Ventricular / mortality*
  • Tachycardia, Ventricular / physiopathology
  • Terminology as Topic*
  • Ventricular Fibrillation / classification
  • Ventricular Fibrillation / diagnosis
  • Ventricular Fibrillation / mortality*
  • Ventricular Fibrillation / physiopathology
  • Young Adult