Chapter 61

Traumatic Heart Disease

Fernando Boccalandro, MD, FACC, FSCAI

1. What is the most common cause of cardiac injury?

    Motor vehicle accidents are the most common cause of cardiac injury.

2. List the physical mechanisms of injury in cardiac trauma.

    Physical mechanisms of injury include penetrating trauma (i.e., ribs, foreign bodies, sternum); nonpenetrating trauma (or blunt cardiac injury); massive chest compression (or crush injury); deceleration, traction, or torsion of the heart or vascular structures; and sudden rise in blood pressure caused by acute abdominal compression.

3. What is myocardial contusion?

    Myocardial contusion is a common form of blunt cardiac injury; it is considered a reversible insult and is the consequence of a nonpenetrating myocardial trauma. It is detected by elevations of specific cardiac enzymes with no evidence of coronary occlusion, and by reversible wall motion abnormalities detected by echocardiography. It can manifest in the electrocardiogram (ECG) by ST-T wave changes or by arrhythmias. Myocardial contusion is pathologically characterized by areas of myocardial necrosis and hemorrhagic infiltrates that can be recognized on autopsy.

4. Which major cardiovascular structures are most commonly involved in cardiac trauma?

    Cardiac trauma most commonly involves traumatic contusion or rupture of the right ventricle (RV), aortic valve tear, left ventricle (LV) or left atrial rupture, innominate artery avulsion, aortic isthmus rupture (Fig. 61-1), left subclavian artery traumatic occlusion, and tricuspid valve tear.

Figure 61-1 Traumatic rupture of the descending thoracic aorta (arrows) at the aortic isthmus. Modified from Valji K: Vascular and Interventional Radiology, ed 2, Philadelphia, 2006, Saunders.

5. What bedside findings can be detected in patients with suspected major cardiovascular trauma?

    Obvious clinical signs in patients with nonpenetrating trauma are rare. However, a bedside evaluation by an astute clinician to detect possible life-threatening cardiovascular and thoracic complications can reveal important signs in just a few minutes (Table 61-1).

TABLE 61-1

IMPORTANT SIGNS OF CARDIOVASCULAR AND THORACIC TRAUMA

Finding	Suggested Lesions
Pale skin color, conjunctiva, palms, and oral mucosa	Suggests important blood loss
Decreased blood pressure in the left arm	Seen in patients with traumatic rupture of the aortic isthmus, pseudocoarctation, or traumatic thrombosis of the left subclavian artery
Decreased blood pressure in the right arm	Consider innominate artery avulsion
Subcutaneous emphysema and tracheal deviation	Consider pneumothorax
Elevated jugular venous pulse with inspiratory raise (i.e., the Kussmaul sign)	Suggests cardiac tamponade or tension pneumothorax
Prominent systolic V wave in the venous pulse examination	Suggests tricuspid insufficiency as a result of tricuspid valve tear
Nonpalpable apex or distant heart sounds	Suspect cardiac tamponade
Pericardial rub	Diagnostic for pericarditis
Pulsus paradoxus	Seen in patients with cardiac tamponade, massive pulmonary embolism, or tension pneumothorax
Continuous murmurs or thrills	Consider traumatic arteriovenous fistula or rupture of the sinus of Valsalva
Harsh holosystolic murmurs	Suspect traumatic ventricular septal defect
Early diastolic murmur and widened pulse pressure	Suspect aortic valve injury
Cervical and supraclavicular hematomas	Seen in traumatic carotid rupture
New focal neurological symptoms	Traumatic carotid, aortic, or great vessel dissection

6. Can an acute myocardial infarction complicate cardiac trauma?

    Myocardial infarction is an unusual complication in patients with chest trauma. Chest trauma can injure a coronary artery, leading to myocardial infarction due to coronary spasm, thrombosis, laceration, or dissection of the arterial wall. Patients with underlying coronary artery disease have favorable pathophysiologic conditions to suffer an acute coronary syndrome during trauma, as a result of limited coronary flow reserve, excess of circulating catecholamines, hypoxia, blood loss, and hypotension. It may be relevant in the appropriate clinical scenario to consider the possibility of cardiac syncope as the primary cause resulting in a traumatic event due to ventricular arrhythmias in a patient with an acute myocardial infarction and concomitant trauma. Chest trauma can elevate cardiac-specific enzymes without significant coronary stenosis; therefore, careful interpretation of these indicators in a trauma victim is warranted.

7. What is the most common type of myocardial infarction suffered in trauma victims?

    According to the universal definition of myocardial infarction, patients who have myocardial necrosis during trauma usually suffer a type 2 myocardial infarction. This type of myocardial necrosis is secondary to direct trauma or ischemia, and is a result of a relative imbalance of either increased myocardial oxygen demand or decreased myocardial oxygen supply (e.g., coronary artery spasm, coronary embolism, anemia, arrhythmias, hypertension, anemia, or hypotension), rather than coronary occlusion caused by advanced atherosclerosis or an acute coronary thrombotic event (type 1 myocardial infarction), and is characterized by a variable increase in cardiac biomarkers with no ischemic symptoms or ECG changes.

8. What is the preferred treatment for an ST elevation acute myocardial infarction in the event of chest trauma?

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Related posts:

1. Cardiovascular Physical Examination
2. Stroke and Transient Ischemic Attack
3. Endomyocardial Biopsy
4. Pulmonary Hypertension

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