Blunt, non-penetrating trauma of the chest (commotio cordis) can cause sudden 
death in individuals without known cardiac disease. Sudden death in commotio 
cordis is due to ventricular fibrillation. The timing of the blow must be during 
the electric vulnerable period of the ECG cyclus, 10-40 milliseconds before the 
peak of the T-wave. The risk of arrhythmia increases progressively, until a 
velocity of 64 km/h, and at higher velocities the risk of ventricular 
fibrillation begins to diminish. The location of the impact must be directly 
over the cardiac silhouette.