Chapter 104: Traumatic Heart Disease
What percentage of traumatic cardiac penetration injuries are lethal?
The answer is E. (Hurst’s The Heart, 14th Edition, Chap. 104) Traumatic cardiac penetration injuries are highly lethal at 70% to 80% (option E). Penetrating injury to the heart must be suspected with any missile or knife wound to the thorax or upper abdomen. The mechanism of injury may be categorized as low, medium, or high velocity. Knife wounds are low velocity, shotgun injuries are medium velocity, and high-velocity injuries include bullet wounds caused by rifles and wounds resulting from military and civilian weapons. The amount of tissue damage is directly related to the amount of energy exchange between the penetrating object and the body part.1
A 30-year-old man is brought to the emergency room following a stab wound to the left upper quadrant of his anterior chest. Which region of the heart is most likely to have been penetrated?
The answer is A. (Hurst’s The Heart, 14th Edition, Chap. 104) The anteriorly positioned right ventricle is most frequently injured (option A), followed by the left ventricle (option B), right atrium (option C), and left atrium (option D) (see Table 104-1 of Hurst’s The Heart, 14th Edition).2 Other potentially injured structures include the interatrial or interventricular septum, coronary arteries, valves, subvalvular apparatus, and conduction system.3 Low-velocity injuries, such as stab wounds, produce damage commensurate to the structure penetrated and the size of the defect. High-velocity missiles produce injury beyond the region of myocardial penetration secondary to concussive effects and are more frequently lethal.4-7 The primary manifestations of cardiac penetration are hemorrhage and tamponade. Valve or coronary injury may, of course, produce acute valvular incompetence or myocardial infarction. Stab victims often present with tamponade when clot and surrounding pericardial fat partially seal the pericardial defect. Injuries to the left ventricle more commonly result in overt hemorrhage. Patients presenting with tamponade may have a survival advantage, with mortality rates as low as 8% in experienced trauma centers.4 Early diagnosis is critical to survival, and this is only possible with a high index of suspicion, bearing in mind that patients with potentially fatal wounds can be stable at ...