Commotio cordis

Biomechanical considerations for assessing interactions of children and small occupants with inflatable seat belts

NHTSA estimates that more than half of the lives saved (168,524) in car crashes between 1960 and 2002 were due to the use of seat belts. Nevertheless, while seat belts are vital to occupant crash protection, safety researchers continue efforts to further enhance the capability of seat belts in reducing injury and fatality risk in automotive crashes. Examples of seat belt design concepts that have been investigated by researchers include inflatable, 4-point, and reverse geometry seat belts. In 2011, Ford Motor Company introduced the first rear seat inflatable seat belts into production vehicles. A series of tests with child and small female-sized Anthropomorphic Test Devices (ATD) and small, elderly female Post Mortem Human Subjects (PMHS) was performed to evaluate interactions of prototype inflatable seat belts with the chest, upper torso, head and neck of children and small occupants, from infants to young adolescents. Tests simulating a 6-year-old child asleep in a booster seat, with its head lying directly on its shoulder on top of the inflatable seat belt, were considered by engineering judgment, to represent a worst case scenario for interaction of an inflating seat belt with the head and neck of a child and/or small occupant. All evaluations resulted in ATD responses below Injury Assessment Reference Values reported by Mertz et al. (2003). In addition, the tests of the PMHS subjects resulted in no injuries from interaction of the inflating seat belt with the heads, necks, and chests of the subjects. Given the results from the ATD and PMHS tests, it was concluded that the injury risk to children and small occupants from deployment of inflatable seat belt systems is low.

[Sudden cardiac death in young athletes]

Cardiovascular diseases are the cause of death in up to 90% of athletes. The most frequent cause of death in young athletes is a sudden cardiac death (SCD). Causes of SCD among athletes are strongly correlated with age. In young athletes (< 35 years), the leading causes are congenital cardiac diseases, particularly hypertrophic cardiomyopathy and congenital coronary artery anomalies. By contrast, most of deaths in older athletes (< 35 years) are due to coronary artery disease. Although there is no possibility to decrease the risk of SCD to "zero", especially in sport competitions, clear recommendations, if available, for cardiovascular evaluation before athletic participation and side effects of sports activities, would minimize the frequency of SCD. If a specific condition of the cardiovascular system is diagnosed, it is necessary to establish the risk of SCD associated with a continual involvement in physical activities and competitive sports, and to define clearly disqualification criteria for each individual athlete.

Safety baseballs and chest protectors: a systematic review on the prevention of commotio cordis

OBJECTIVE

To determine whether chest protectors and/or safety baseballs reduce the incidence of commotio cordis during sport through a review of the best available evidence.

DATA SOURCES

PubMed, Ovid Medline, and Embase databases from 1950 to 2009. We selected articles according to "death, sudden, cardiac," "commotio cordis," "sports equipment," and "protective devices." We identified 17 articles in the systematic literature search. Of these, 7 articles met inclusion criteria. Three independent reviewers reviewed the articles. The study results and generated conclusions were extracted and agreed on.

RESULTS

The softest safety baseball shows statistically significant reductions in the incidence of ventricular fibrillation (VF) at all velocities compared with standard baseballs in the 3 studies that evaluated their use. Different degrees of softness did not show statistically significant reductions in VF. In the 3 studies that evaluated the use of chest protectors against controls, there was an increase in protection against fatal arrhythmias; however, this was only statistically significant for 1 chest protector.

CONCLUSIONS

This systematic review shows strong supportive evidence toward a decreased rate of commotio cordis with safety baseballs when compared with standard balls. Based on the results of our systematic review, the rate of induction of VF was at its lowest when chest protection was used.

Cardiac concussion (commotio cordis)

Blunt chest trauma in pediatric patients can result in various injuries to the myocardium. Cardiac concussion (commotio cordis) is seen in patients in whom the precordium has been struck with relatively little force at a vulnerable period of the cardiac cycle. These patients have no predisposing cardiac problems, and autopsy reveals no evidence of heart damage. The usual clinical presentation is that of immediate collapse secondary to a lethal arrhythmia. Prevention is the cornerstone of potentially decreasing the incidence with the aid of safety equipment and, possibly, immediate defibrillation.