Commotio Cordis (CC) is the second leading cause of mortality in youth sports. 
Impacts occurring directly over the left ventricle (LV) during a vulnerable 
period of the cardiac cycle can cause ventricular fibrillation (VF), which 
results in CC. In order to better understand the pathophysiology of CC, and 
develop a mechanical model for CC, appropriate injury criteria need to be 
developed. This effort consisted of impacts to seventeen juvenile porcine 
specimens (mass 21-45 kg). Impacts were delivered over the cardiac silhouette 
during the venerable period of the cardiac cycle. Four impact speeds were used: 
13.4, 17.9, 22.4, and 26.8 m/s. The impactor was a lacrosse ball on an aluminum 
shaft instrumented with an accelerometer (mass 188 g-215 g). The impacts were 
recorded using high-speed video. LV pressure was measured with a catheter. 
Univariate binary logistic regression analyses were performed to evaluate the 
predictive ability of ten injury criteria. A total of 187 impacts were used in 
the analysis. The criteria were evaluated on their predictive ability based on 
Somers' D (D) and Goodman-Kruskal gamma (γ). Injury risk functions were created 
for all criteria using a 2-parameter Weibull distribution using survival 
analysis. The best criteria for predicting CC were impact force (D=0.52, and 
γ=0.52) force*compression (D=0.49, and γ=0.49), and impact power (D=0.49, and 
γ=0.49). All of these criteria proved significant in predicting the probability 
of CC from projectile impacts in youth sports (p<0.01). Force proved to be the 
most predictive of the ten criteria evaluated.