Impact directly over the cardiac silhouette is necessary to produce ventricular fibrillation in an experimental model of commotio cordis
Mark S. Link, MD, FACC*,
Barry J. Maron, MD, FACC ,
Brian A. VanderBrink, BS*,
Masaaki Takeuchi, MD*,
Natesa G. Pandian, MD, FACC*,
Paul J. Wang, MD, FACC* and
N. A. Mark Estes, III, MD, FACC*
* Center for the Cardiovascular Evaluation of Athletes, The Cardiac Arrhythmia Center, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
Cardiovascular Research Division, Minneapolis Heart Institute Foundation, Minneapolis, Minnesota, USA
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Figure 1 Impact sites used in this experimental model of commotio cordis. All chest blows were delivered with a regulation baseball at 30 mph. The LV anterolateral papillary muscle and base and apex of the LV were defined by direct anatomic visualization with transthoracic echocardiography. Distances to the other chest wall sites (unrelated to the heart) were defined using the papillary muscle as a reference point. Not shown here are the right chest wall sites. LA = left atrium; LV = left ventricle; RV = right ventricle.
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Figure 2 Six-lead electrocardiogram demonstrating VF produced by a 30-mph baseball impact to the chest wall directly over the anterolateral papillary muscle, timed to the upstroke of the T wave in an 11-kg juvenile swine. Ventricular fibrillation occurs immediately and is not preceded by ischemic electrocardiographic changes, ventricular tachycardia or heart block. Inset (lower right). Magnification of the LV pressure tracing obtained at the precise moment of impact; note the marked and immediate pressure rise within the LV. Left ventricular pressure increases abruptly to 290 mm Hg over a time period of 8 ms and falls to 0 mm Hg 12 ms later. LV = left ventricular; VF = ventricular fibrillation.
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Figure 3 Bar graph demonstrating the occurrence of VF as a result of 30-mph baseball impacts with respect to different sites on the chest wall of swine in our experimental model of commotio cordis. Ventricular fibrillation was produced only by impacts directly over the cardiac silhouette with the highest incidence evident at the center of the LV. Ventricular fibrillation was not produced with impacts at the right and left lateral (Lat) or the right and left posterior (Post) chest wall sites. LV = left ventricle; VF = ventricular fibrillation.
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Figure 4 Logistic regression plot showing the significant correlation between the risk of VF induction with baseball impact to the chest wall at 30 mph and the peak LV pressure resulting immediately after the blow. LV = left ventricular; VF = ventricular fibrillation.
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