BACKGROUND: Commotio cordis is a term used to describe cases of blunt thoracic 
impact causing fatality without gross structural damage of the heart and 
internal organs. Death is attributed to ventricular fibrillation or cardiac 
arrhythmia aggravated by traumatic apnea. The biomechanical response related to 
the risk of commotio cordis has not been determined.
METHODS: Reanalysis of previously published experimental data was performed to 
determine which biomechanical parameter predicts the occurrence of commotio 
cordis. Logistic regression was used to determine the risk for commotio cordis 
with the level of chest compression, rate of chest deformation, and viscous 
criterion.
RESULTS: By using only cases without serious tissue injury (Abbreviated Injury 
Scale score < 4), viscous criterion was the best predictor of commotio cordis or 
ventricular fibrillation (chi2 = 7.69, p = 0.006). It was also the best 
predictor of heart rupture (chi2 = 13.19,p = 0.0003) and severe cardiac injury 
with Abbreviated Injury Scale score > or = 4 (chi2 = 25.03, p = 0.0001).
CONCLUSION: Based on this in-depth analysis, the viscous criterion is the 
relevant biomechanical response to assess the risk of commotio cordis and more 
severe thoracic injury in high-speed blunt impact.