Size as an Important Determinant of Chest Blow–induced Commotio Cordis

PURPOSECommotio cordis is sudden cardiac death caused by a relatively innocent blow to the left chest wall. Adolescents account for the majority of the cases; whether this is due to the higher frequency of adolescents playing ball sports or whether there is some maturational reduction of risk is not known. METHODSIn a swine model of commotio cordis, the effect of body weight/size (directly related to age) to the susceptibility of chest impact–induced ventricular fibrillation (VF) is examined. METHODSBall impacts were delivered at escalating velocities from 48.3 to 96.9 km·h (30–60 mph) to 128 swine ranging in weight from 5 to 54 kg. RESULTSVF occurred in 29% of impacts to the smallest animals compared with 34% in the 14- to 239-kg group, 27% in the 24- to 33.9-kg group, 30% in 34- to 43-kg group, and 15% in the 44- to 54-kg animals. The highest-weight group was associated with a significantly lower incidence of VF compared with other weights (P = 0.002). In a multivariate logistic regression analysis, controlling for repeated measures, four variables predicted VFbody weight (P = 0.0008), velocity (P < 0.0001), distance from the center of the heart, (P < 0.0001), and peak left ventricular pressure induced by the blow (P = 0.0007). CONCLUSIONSIn this experimental model, animals weighing