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Emergency and Acute Medicine – Myocardial Contusion
Myocardial contusion, also referred to as blunt cardiac injury (BCI), is a form of cardiac trauma resulting from blunt force to the chest. Pathologically, it is characterized by a discrete, well-demarcated area of myocardial hemorrhage, most commonly involving the subendocardium. In some cases, the injury may extend in a pyramidal, transmural fashion. Due to its anatomic position, the anterior wall of the right ventricle or right atrium is most frequently affected.
The etiology of myocardial contusion is blunt chest trauma. High-speed motor vehicle collisions are the most common cause, although injuries have been reported at speeds as low as 20–35 mph. Other mechanisms include auto–pedestrian accidents, falls, explosions, crush injuries, and prolonged closed-chest cardiac massage. Injury may occur through direct compression of the heart between the sternum and vertebral column, deceleration forces causing the heart to strike the sternum, or upward displacement of abdominal viscera transmitting force to the heart. Concussive forces may also contribute. Myocardial contusion may be associated with serious complications, including life-threatening dysrhythmias, cardiogenic shock, congestive heart failure, hemopericardium with tamponade, valvular or myocardial rupture, intraventricular thrombus, thromboembolic events, and, rarely, coronary artery occlusion due to intimal injury or edema.
Clinical presentation is highly variable and often nonspecific. Patients may complain of chest pain, develop cardiogenic shock, or exhibit only subtle electrocardiographic changes without symptoms. The most common clinical finding is sinus tachycardia that appears disproportionate to the degree of trauma or blood loss. Retrosternal chest pain, often unrelieved by nitroglycerin, may be delayed for up to 24 hours and may respond to supplemental oxygen. Other findings include friction rubs (rare), signs of thoracic trauma such as contusions or abrasions, crepitus, flail chest segments, or sternal fractures. Importantly, isolated sternal fracture with a normal ECG and negative serial troponin I does not predict blunt cardiac injury. Symptoms may be masked by other traumatic injuries. A history of syncope or loss of consciousness raises concern for dysrhythmia. In elderly patients, pre-existing cardiac disease and medications must be carefully considered, while in pediatric patients significant cardiac injury may occur despite minimal external signs due to the compliance of the chest wall.
There is no single diagnostic test that definitively confirms myocardial contusion. Electrocardiography is the best initial screening tool and should be obtained in all patients with suspected blunt cardiac injury. Sinus tachycardia is the most common finding, but ECG abnormalities may include nonspecific ST changes, right bundle branch block, or premature atrial or ventricular contractions. A normal ECG does not exclude myocardial injury, and repeat ECGs are recommended because abnormalities may evolve over time. Cardiac troponin I is the preferred laboratory marker and should be obtained in conjunction with ECG findings; levels should be repeated at 6–8 hours after injury. Any elevation warrants admission. Echocardiography is indicated in patients with ECG abnormalities or elevated troponins to assess for wall-motion abnormalities, effusions, or structural injury. Transesophageal echocardiography is more sensitive than transthoracic echocardiography but is more invasive. FAST examination should be performed to assess for pericardial effusion and associated intra-abdominal injuries. CT or MRI may assist in evaluating associated thoracic injuries but have no pathognomonic findings for myocardial contusion.
Management in the emergency setting focuses on supportive care and treatment of complications. Airway management, oxygen supplementation, intravenous access, and continuous cardiac monitoring are essential. Dysrhythmias are treated using standard protocols for nontraumatic arrhythmias, and prophylactic antiarrhythmic therapy is not recommended. Cardiogenic shock should be managed with cautious fluid resuscitation and inotropic support when necessary, with intra-aortic balloon counterpulsation reserved for severe cases. There is no specific therapy to reverse myocardial contusion itself; treatment is directed toward hemodynamic stabilization and management of associated injuries.
Disposition decisions require caution, as adverse outcomes—particularly dysrhythmias—most often occur within the first 24 hours. All patients in whom myocardial contusion is strongly suspected should be admitted to a monitored setting. Admission is indicated for any ECG abnormality, elevated cardiac enzymes, hemodynamic instability, or imaging suggestive of cardiac injury. Asymptomatic patients with normal ECGs and normal serial troponin I levels after 6–8 hours of observation may be safely discharged with close follow-up within 24 hours.
Key clinical pearls include the importance of obtaining an ECG in all patients with significant chest trauma and performing a FAST examination to assess for pericardial effusion. External signs of chest wall injury should heighten suspicion for blunt cardiac injury, while their absence—especially in pediatric patients—does not exclude it. Thrombolytic therapy should not be administered for ST-elevation myocardial infarction following trauma. A normal ECG combined with a negative troponin I level makes clinically significant blunt cardiac injury unlikely.
Myocardial contusion, also referred to as blunt cardiac injury (BCI), is a form of cardiac trauma resulting from blunt force to the chest. Pathologically, it is characterized by a discrete, well-demarcated area of myocardial hemorrhage, most commonly involving the subendocardium. In some cases, the injury may extend in a pyramidal, transmural fashion. Due to its anatomic position, the anterior wall of the right ventricle or right atrium is most frequently affected.
The etiology of myocardial contusion is blunt chest trauma. High-speed motor vehicle collisions are the most common cause, although injuries have been reported at speeds as low as 20–35 mph. Other mechanisms include auto–pedestrian accidents, falls, explosions, crush injuries, and prolonged closed-chest cardiac massage. Injury may occur through direct compression of the heart between the sternum and vertebral column, deceleration forces causing the heart to strike the sternum, or upward displacement of abdominal viscera transmitting force to the heart. Concussive forces may also contribute. Myocardial contusion may be associated with serious complications, including life-threatening dysrhythmias, cardiogenic shock, congestive heart failure, hemopericardium with tamponade, valvular or myocardial rupture, intraventricular thrombus, thromboembolic events, and, rarely, coronary artery occlusion due to intimal injury or edema.
Clinical presentation is highly variable and often nonspecific. Patients may complain of chest pain, develop cardiogenic shock, or exhibit only subtle electrocardiographic changes without symptoms. The most common clinical finding is sinus tachycardia that appears disproportionate to the degree of trauma or blood loss. Retrosternal chest pain, often unrelieved by nitroglycerin, may be delayed for up to 24 hours and may respond to supplemental oxygen. Other findings include friction rubs (rare), signs of thoracic trauma such as contusions or abrasions, crepitus, flail chest segments, or sternal fractures. Importantly, isolated sternal fracture with a normal ECG and negative serial troponin I does not predict blunt cardiac injury. Symptoms may be masked by other traumatic injuries. A history of syncope or loss of consciousness raises concern for dysrhythmia. In elderly patients, pre-existing cardiac disease and medications must be carefully considered, while in pediatric patients significant cardiac injury may occur despite minimal external signs due to the compliance of the chest wall.
There is no single diagnostic test that definitively confirms myocardial contusion. Electrocardiography is the best initial screening tool and should be obtained in all patients with suspected blunt cardiac injury. Sinus tachycardia is the most common finding, but ECG abnormalities may include nonspecific ST changes, right bundle branch block, or premature atrial or ventricular contractions. A normal ECG does not exclude myocardial injury, and repeat ECGs are recommended because abnormalities may evolve over time. Cardiac troponin I is the preferred laboratory marker and should be obtained in conjunction with ECG findings; levels should be repeated at 6–8 hours after injury. Any elevation warrants admission. Echocardiography is indicated in patients with ECG abnormalities or elevated troponins to assess for wall-motion abnormalities, effusions, or structural injury. Transesophageal echocardiography is more sensitive than transthoracic echocardiography but is more invasive. FAST examination should be performed to assess for pericardial effusion and associated intra-abdominal injuries. CT or MRI may assist in evaluating associated thoracic injuries but have no pathognomonic findings for myocardial contusion.
Management in the emergency setting focuses on supportive care and treatment of complications. Airway management, oxygen supplementation, intravenous access, and continuous cardiac monitoring are essential. Dysrhythmias are treated using standard protocols for nontraumatic arrhythmias, and prophylactic antiarrhythmic therapy is not recommended. Cardiogenic shock should be managed with cautious fluid resuscitation and inotropic support when necessary, with intra-aortic balloon counterpulsation reserved for severe cases. There is no specific therapy to reverse myocardial contusion itself; treatment is directed toward hemodynamic stabilization and management of associated injuries.
Disposition decisions require caution, as adverse outcomes—particularly dysrhythmias—most often occur within the first 24 hours. All patients in whom myocardial contusion is strongly suspected should be admitted to a monitored setting. Admission is indicated for any ECG abnormality, elevated cardiac enzymes, hemodynamic instability, or imaging suggestive of cardiac injury. Asymptomatic patients with normal ECGs and normal serial troponin I levels after 6–8 hours of observation may be safely discharged with close follow-up within 24 hours.
Key clinical pearls include the importance of obtaining an ECG in all patients with significant chest trauma and performing a FAST examination to assess for pericardial effusion. External signs of chest wall injury should heighten suspicion for blunt cardiac injury, while their absence—especially in pediatric patients—does not exclude it. Thrombolytic therapy should not be administered for ST-elevation myocardial infarction following trauma. A normal ECG combined with a negative troponin I level makes clinically significant blunt cardiac injury unlikely.
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