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Electro-chemomechanical couplings
Published in Benjamin Loret, Fernando M. F. Simões, Biomechanical Aspects of Soft Tissues, 2017
Benjamin Loret, Fernando M. F. Simões
Stretch-activated ionic channels located on the membrane of cardiac cells (SACs) are still subject to debate because they have not been cloned in adult mammalian myocytes but observed in cultured cells and in young cells. Interest in these channels has been renewed due to their link to commotio cordis which is observed in young adults, because they may originate arrhythmia and fibrillation. The Oxford group has contributed to suggest models and to stress the physiological importance of the phenomemon, Kohl and Sachs [2001]. Commotio cordis is associated with the impact of a projectile on the chest leading to sudden cardiac death, but without creating material damage. In fact, the potential danger of such impacts depends much on the precise time during the heart beat at which they occur: they are much more dangerous if applied during diastole.
Designing for Upper Torso and Arm Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
Every year, 10 to 20 people in the U. S. suffer commotio cordis, cardiac arrest caused by a blow to the chest (Link, 2012). A projectile traveling at about 40 miles per hour must land directly over the heart, in the milliseconds between heartbeats, to stop the heart. Deaths have occurred despite wearing a protective vest. The National Operating Committee on Standards for Athletic Equipment (2017) issued a standard for chest protectors worn by lacrosse and baseball players, effective June 2018. Kumar et al. (2017) achieved effective chest wall protection with a novel pad of modest thickness in an animal model of commotio cordis. They propose further development of chest protector designs with the same materials for use on the playing field. Designers of bullet and blast resistant vests for police officers and military personnel face the challenge of designing a product that can stop bullets or bomb fragments and be comfortable for daily wear. Bullet-resistant vests can be made of rigid materials—ceramic shields placed into vests—or high-strength fiber textiles that are more comfortable and yet provide adequate protection. Although quite successful in protecting against penetrating injuries, body armor “flak” jackets can transmit force to the body, causing “behind armour blunt trauma” (Carr, 2016, p. 261). Couldrick (2004) states, “Good armour design is a matter of making the best of a bad situation” (p. 213). He notes that materials technology, threat, wearer, task, and environment are the pertinent considerations for body armor design. A vest that physically protects against bullet penetration but is too heavy, hot, or cumbersome will not be worn—offering no protection. Additionally, the designer has to balance financial cost with protection and ergonomic effectiveness. For a review of the features and design of bullet-resistant equipment, see Watkins and Dunne’s (2015, Chapter 6) discussion of impact protective materials and products. Another functional military garment uses the rib cage as a support structure. A vest designed for combat radio operators incorporates a radio antenna in the vest materials, eliminating a visible antenna that projects above the soldier’s head (Lebaric, Adler, & Limbert, 2001).
Developing commotio cordis injury metrics for baseball safety: unravelling the connection between chest force and rib deformation to left ventricle strain and pressure
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Grant J. Dickey, Kewei Bian, Habib R. Khan, Haojie Mao
Commotio cordis (CC) refers to sudden death from low-energy non-penetrating chest impacts over the cardiac silhouette in the absence of structural heart disease. Defined as a cardiac concussion, commotio cordis shows no signs of structural damage to the heart post-impact (Maron et al. 1995; Pearce 2005). According to the US Commotio Cordis Registry (USCCR) in Minneapolis, there are currently over 200 confirmed cases worldwide (Maron and Estes 2010; Link 2012). Although the occurrence rate of commotio cordis is low, most cases are fatal (Drewniak et al. 2007). Commotio cordis can happen in a wide variety of circumstances; ranging from casual play in a backyard or playground, to competitive hockey, lacrosse or baseball games (Kaplan et al. 1993; Maron and Estes 2010). Meanwhile, the statistics in cases are believed to be strongly influenced by the lack of awareness towards commotio cordis, suggesting that there are many more cases of the sudden death mechanism that have gone unreported (Maron and Estes 2010).