Blunt chest trauma can induce myocardial lesions by several mechanisms, including direct transfer of kinetic energy during the impact on the chest, a sudden forceful deceleration process of the heart, and compression of heart between the sternum and the spine.1 Direct injury by a fractured sternum may damage the right ventricle. Another mechanism is an abrupt blood pressure increase in cardiac chambers after chest or abdominal compression or crushing.2,12 Impact may produce distension, shearing, or rupture of the heart according to the “water hammer effect.”2,12
In the current case report, the blunt cardiac injury resulted from a direct kick impact to the precordial area. The traumatic lesions found at autopsy included one cardiac contusion associated with a hemopericardium and a pulmonary contusion. In our case, hemopericardium could be secondary to the myocardial contusion as no pericardial tears or injury of intrapericardial portion of a major vessel were found. The practice of a long-standing resuscitation could have contributed to the abundance of the hemopericardium. Indeed, CPR is known to cause a variety of cardiovascular injury in adults.13 Fractured ribs from CPR may perforate the heart and excessive vigor in performing CPR has been blamed for a rupture of the interventricular septum and right ventricle.6 In the autopsy series of Krischer et al,13 8.4% of the cases were found to have whole blood in the pericardial sac as a complication of CPR. Other cardiac injuries included ventricular subendocardial contusion and laceration of the right atrium.13 Significant injuries to the cardiac conduction system after CPR, especially external chest compression, have been recently described in case report14 and in a large autopsy series.15
In our case, the pathologic changes found were typical for a cardiac contusion. The morphology of a cardiac contusion resembles those of acute myocardial infarction, but the amount of hemorrhage is more prominent in case of contusion. In addition, contusion presents an abrupt change between normal and abnormal myocardium, whereas the changes related to infarction are more gradual.8 In our case, there were also no coronary artery disease and no epicardial coronary artery trauma. The numerous foci of perivascular hemorrhages found away from the macroscopic heart contusion showed that severe shearing strains were applied to the heart. Indeed, they can be considered as micro tears of the myocardium with surrounding hemorrhage. The intensity of such shearing strains depends of the amount of kinetic energy delivered in the chest area after the blunt impact. There is some evidence that the absence of rib fractures-a common feature with young people-in cases of chest trauma may be associated with more severe cardiac injury.2 In our case, as the energy of forces was not dissipated by the fracturing of sternum or ribs, almost the whole amount of kinetic energy was delivered on the heart. Although the chest trauma was anterior, the macroscopic heart contusion was found in the posterior wall of the heart at autopsy. This can be the result of impact of the heart against the vertebral column.
Concerning the mechanism of death in our case, myocardial contusion may induce life-threatening complications through rhythm abnormalities (including ventricular fibrillation or asystolia), myocardial rupture, or conduction disturbance.16 According to experimental studies on rabbits, a high contusion kinetic energy was found to result in increased arrhythmia seriousness.17 In such experimental animal studies, arrhythmias occurred in up to 50% of cases.18 Arrhythmia occurs as a result of abnormal perfusion patterns, conduction anomalies by damaged myocytes or vagal-sympathetic reflexes.17 Major mechanism of death in our case was tamponade due to hemopericardium. Indeed, hemopericardium may develop acutely or be delayed after myocardium contusion19 and may reach sufficient volume to cause cardiac tamponade.2 As little as 150 mL of blood can cause death.20 Death could be a direct consequence of the myocardial contusion through electrical instability or/and a consequence of the hemopericardium because its volume and sudden apparition were sufficient to provoke tamponade.21 Cardiac contusions are very rarely lethal and in most of the lethal cases fatal outcome is usually caused by associated extracardiac injuries.17 As the lung contusion was found in a small area, it seemed to have played a minor role in the mechanism of death in our case.
One striking element in our case was the importance of serious internal traumatic lesions in contrast with the absence of external sign of chest trauma. This finding underlines the importance of a systematic complete autopsy in all cases of sudden death occurring in young adults, to rule out a possible homicide. This also shows that occult cardiac injury after blunt chest trauma is probably more common than generally suspected in living patients. Indeed, the clinical presentations of such injuries are extremely variable and are frequently unnoticed in the multitraumatized patient.22 So the diagnosis of myocardial contusion must be ruled out in every patient presenting blunt chest trauma even in the absence of external sign.
1. Holanda MS, Dominguez MJ, Lopez-Espadas F, et al. Cardiac contusion following blunt chest trauma. Eur J Emerg Med
2. Menzies RC. Cardiac contusion: a review. Med Sci Law
3. Hossack KF, Moreno CA, Vanway CW, et al. Frequency of cardiac contusion in nonpenetrating chest injury. Am J Cardiol
4. Vougiouklakis T, Peschos D, Doulis A, et al. Sudden death from contusion of the right atrium after blunt chest trauma: case report and review of the literature. Injury
5. Zhu BL, Fujita MQ, Quan L, et al. A sudden death due to cardiac conduction system injury from a blunt chest impact. Legal Med
6. Cohle SD, Hawley DA, Berg KK, et al. Homicidal cardiac lacerations in children. J Forensic Sci
7. Nadesan K. Murder and robbery by vehicular impact: true vehicular homicide. Am J Forensic Med Pathol
8. Boglioli LR, Taff ML, Harleman G. Child homicide caused by commotio cordis. Pediatr Cardiol
9. Denton JS, Kalelkar MB. Homicidal commotio cordis in two children. J Forensic Sci
10. Baker AM, Craig BR, Lonergan GJ. Homicidal commotio cordis: the final blow in a battered infant. Child Abuse Negl
11. Altun G, Altun A, Yilmaz A. Hemopericardium-related fatalities: a 10-year medicolegal autopsy experience. Cardiology
12. Turillazzi E, Pomara C. Cardiovascular traumatic injuries. In: Fineschi V, Baroldi G, Silver MD, eds. Pathology of the Heart and Sudden Death in Forensic Medicine
. Boca Raton, FL: CRC Press; 2006:303–326.
13. Krischer JP, Fine EG, Davis JH, et al. Complications of cardiac resuscitation. Chest
14. Rossi L, Matturi L. His bundle haemorrhage and external cardiac massage: histopathological findings. Br Heart J
15. Nishida N, Chiba T, Ohtani M, et al. Relationship between cardiopulmonary resuscitation and injuries of the cardiac conduction system: pathological features and pathogenesis of such injuries. Crit Care Med
16. Liedtke AJ, DeMuth WE Jr. Nonpenetrating cardiac injuries: a collective review. Am Heart J
17. Darok M, Beham-Schmid C, Gatterning R, et al. Sudden death from myocardial contusion following an isolated blunt force trauma to the chest. Int J Legal Med
18. Maron BJ, Poliac LC, Kaplan JA, et al. Blunt impact to the chest leading to sudden death from cardiac arrest during sport activities. N Engl J Med
19. Tenzer ML. The spectrum of myocardial contusion: a review. J Trauma
20. DiMaio VJ, DiMaio D. Forensic Pathology
. 2nd ed. Boca Raton, FL: CRC Press; 2001:119–122.
21. Spodick DH. Acute cardiac tamponade. N Eng J Med
22. Shorr RM, Crittenden M, Indeck M, et al. Blunt thoracic trauma: analysis of 515 patients. Ann Surg