Reduced diameter spheres increases the risk of chest blow-induced ventricular fibrillation (commotio cordis).

摘要

BACKGROUND: Sudden death due to low-energy blunt trauma to the precordium (commotio cordis) has been described with a variety of sporting objects. However, the risk of ventricular fibrillation (VF) relative to the shape of the impact object is not known. OBJECTIVE: The objective of the current experiment is to test whether the impact object shape is a clinical variable that affects the risk for commotio cordis. METHODS: In a juvenile swine model, impacts were given in random order with two different spherical shapes (72 mm diameter, equivalent to a baseball; 42 mm diameter, equivalent to a golf ball) and a flat round object 72 mm in diameter. Objects were equal in weight (150 g), thrown at 30 mph, and gated to the vulnerable portion of the cardiac cycle. RESULTS: Sixteen swine received 144 impacts. The flat object did not cause VF (P = .01 compared with the two spherical objects), nonsustained VF, ST elevation, or bundle branch block. The smaller diameter sphere caused VF in nine of 48 impacts (19%), and the larger diameter sphere caused VF in five of 48 impacts (10%; P = .25). The smaller diameter sphere was associated with a greater increase in left ventricular pressure (P <.0001 and P = .001 compared with larger sphere only) and a higher likelihood of ST segment elevations (P <.001 and P = .08 compared with larger sphere only) and bundle branch block (Fisher's exact P = .008, and Fisher's exact P = .18 compared with larger sphere only). CONCLUSION: The shape of the projectile markedly influences the risk of VF from chest wall impact. This effect is likely mediated via a greater increase in left ventricular pressure with smaller diameter objects. Spreading the impact force over a larger area may decrease the risk of sudden death and has implications for the design of protective athletic equipment.