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INTRODUCTION AND EPIDEMIOLOGY
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Detection of cardiac injuries is critical for patient survival. Penetrating cardiothoracic injury causes 25% of deaths immediately following trauma, and the majority of these fatalities involve either cardiac or great vessel injury.1 Cardiac injury may account for up to approximately 10% of deaths from gunshot wounds.2 The incidence of blunt cardiac injury has been reported to range anywhere from 8% to 71%.3 Suspect the diagnosis of cardiac and great vessel injury in a patient with chest, lower neck, epigastric, or precordial injury. Closely observe for evidence of hemodynamic instability, loss of circulating blood volume, electrocardiographic changes, cardiac tamponade, and hemothorax.
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Penetrating cardiac injury results when a foreign object enters the body and pierces the pericardium or heart. Blunt cardiac injury results from physical forces acting externally on the body. Iatrogenic injuries to the heart are due to the invasive nature of procedures. All invasive cardiac procedures and therapies have the potential to cause trauma to both the pericardium and myocardium. Even noncardiac procedures like central lines placed into the internal jugular vein can lead to penetration of the pericardium, heart, and great vessels.4
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PENETRATING CARDIAC TRAUMA
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Most injuries occur from guns and knives.5 The injury usually involves only the free cardiac wall, but other structures can be injured, such as cardiac valves, chordae tendineae, papillary muscles, atrial or ventricular septum, coronary arteries, and conduction system (Table 262-1).6
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ANATOMY AND PATHOPHYSIOLOGY
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Pericardial injury can result in acute tamponade. Rates of involvement of cardiac structures due to penetrating injuries to the right ventricle, left ventricle, right atrium, and left atrium are approximately 40%, 35%, 20%, and 5%, respectively.7,8 The right ventricle is at greatest risk due to its large anterior exposure on the chest wall. The right and left atria are less frequently involved due to their smaller surface area. Knives tend to involve a single chamber, producing a single slit-like defect that is often more amenable to medical and surgical therapy than gunshot wounds. Gunshot wounds can leave a spectrum of injury from multiple-chamber perforation to gaping defects depending on the caliber and velocity of the missile. Patients with stab wounds to the heart are 17 times more likely to survive ...