*Introduction*- Commotio cordis 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.^1^ It occurs at a very specific moment (10 to 30 ms) before the peak of the T-wave (repolarization) during the cardiac cycle.^2 ^Currently, the US Commotio Cordis Registry has confirmed over 200 cases worldwide.^3^ While most instances are sport related, commotio cordis can happen in a wide variety of circumstances; ranging from casual play in a backyard, to a competitive hockey, lacrosse or baseball game.^4^ Although occurrence rate is low, statistics are undoubtedly influenced by the lack of awareness towards this sudden death mechanism. Current literature involving swine experiments have suggested that softer baseballs have a favourable outcome in reducing the occurrence of commotio cordis in baseball.^5,6^ This study aims to investigate the ability for softer baseballs to mitigate left ventricle pressure and strain.

*Methods*- Through computational modelling, we simulated 128 impacts, including 4 different baseball stiffness levels (213, 353, 1114, 2533 N/cm), 16 impact locations located on the chest cavity, and 2 impact velocities (13.41 and 17.88 m/s). Left ventricle strain and pressure were analyzed using a computational model. A pareto chart was implemented to compare all 4 baseball stiffness factors to determine which played the most important role regarding strain and pressure development in the left ventricle.

*Results*- The results demonstrated that peak pressure in the left ventricle occurred 2 to 7 ms after contact from the ball to the chest cavity. Peak strain in the left ventricle occurred 5 to 10 ms post-contact. Impact velocity was found to be the most influential for strain, with a peak strain of 0.37 when aimed directly over the left ventricle. Furthermore, impact location was found to be the most important factor affecting left ventricle pressure, with a peak pressure of 82.77 kPa. When analyzing the influence of baseball stiffness for left ventricle strain only a slight reduction was found, and it was a non-significant factor for pressure decrease.  

*Discussion*- A reduction in baseball stiffness did not prove to reduce heart pressure or heart strain, moreover a baseball with a stiffness of 213 N/cm only reduced strain and pressure by 0.4% and 1% when compared to a standard baseball with a stiffness of 2533 N/cm. High impact velocity and specific impact location seems to be the most prominent factor in regards to inducing commotio cordis relevant chest impacts.

*Conclusion*- This detailed computational study helps to address the tissue-level biomechanical mechanisms of commotio cordis. As impact velocity and locations in the transverse and sagittal plane played a vital role in left ventricle strain and pressure, the conventionally used softer baseball was found to have a limited effect on reducing left ventricle strain and pressure response.

 

*References*- 

\[1\] Maron, B.J., Poliac, L.C., Kaplan, J.A., and Mueller, F.O. Blunt impact to the chest leading to sudden death from cardiac arrest during sports activities. *New England Journal of Medicine*, 1995. 

\[2\] Link, M.S., Maron, B.J., et al. Impact directly over the cardiac silhouette is necessary to produce ventricular fibrillation in an experimental model of commotio cordis. *Journal of the American College of Cardiology*, 2001.

\[3\] Maron, B. J., & Estes III, N. M. (2010). Commotio cordis. *New England Journal of Medicine.*

\[4\] Kaplan, J.A., Karofsky, P.S., and Volturo, G.A. Commotio cordis in two amateur ice hockey players despite the use of commercial chest protectors. *The Journal of trauma*, 1993. 

\[5\] Link, M.S., Wang, P.J., et al. An experimental model of sudden death due to low-energy chest-wall impact. *New England Journal of Medicine*, 1998. 338(25).

\[6\] Dau, N., Cavanaugh, J., Bir, C., and Link, M. Evaluation of injury criteria for the prediction of commotio cordis from lacrosse ball impacts. 2011.


Softer Baseballs Do Not Reduce Left Ventricle Pressure and Strain During Commotio Cordis Relevant Chest Impacts

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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