Cardiac Trauma¶

Chapter 283 | Part 6: Disorders of the Cardiovascular System

KEY CLINICAL POINTS¶

Blunt cardiac injury (BCI) is a common cause of cardiac trauma, often resulting from motor vehicle accidents, falls, or sports injuries.
Penetrating cardiac injuries, such as gunshot or stab wounds, are surgical emergencies with high mortality due to hemopericardium and cardiac tamponade.
Cardiac MRI is the gold standard for diagnosing metastatic cardiac tumors, while echocardiography is critical for assessing structural abnormalities in trauma.
Cardiac troponin levels and ECG findings are essential for diagnosing BCI, with normal troponin at 6–8 hours post-injury effectively ruling out BCI.
Pericardiocentesis is lifesaving for tamponade but temporary; surgical intervention is required for persistent effusions or mechanical complications.

1. DEFINITION & OVERVIEW¶

Cardiac trauma encompasses both penetrating and blunt injuries. Blunt cardiac injury (BCI) results from non-penetrating trauma (e.g., motor vehicle accidents), while penetrating injuries involve direct trauma (e.g., gunshot wounds). Cardiac tumors, both primary and metastatic, are also discussed as distinct entities.

Table 283-1 Spectrum of Cardiac Abnormalities Following Blunt Cardiac Injury¶

ABNORMALITY	COMMENTS
ECG abnormalities	Sinus tachycardia, RBBB, heart block, ST-T wave abnormalities, atrial and ventricular arrhythmias
Elevated cardiac Troponin I/T	Most specific biomarkers for myocardial injury
Focal wall motion abnormality	Most commonly involving RV free wall, LV apex, or interventricular septum
Valvular insufficiency	Most commonly mitral and tricuspid valves
Pericardial effusion/tamponade	Resulting from free wall rupture or coronary artery laceration

1.1 Cardiac Trauma Types¶

Blunt cardiac injury (BCI): Non-penetrating trauma causing myocardial contusion, valvular dysfunction, or pericardial effusion. Penetrating injury: Direct trauma from sharp objects or projectiles causing cardiac laceration, rupture, or tamponade.

1.2 Cardiac Tumors¶

Primary cardiac tumors are rare (0.03% of autopsies), with myxomas most common. Metastatic tumors are more prevalent, often from breast, lung, or melanoma primaries. Cardiac lymphoma is the most treatable primary tumor.

2. EPIDEMIOLOGY¶

Blunt cardiac injury occurs in 10–20% of trauma patients, with motor vehicle accidents as the leading cause. Metastatic cardiac tumors are more common than primary tumors, with melanoma, breast, and lung cancers being the most frequent primaries. Cardiac lymphoma has a 40% long-term survival rate with chemotherapy.

2.1 Blunt Cardiac Injury¶

Incidence: 10–20% of trauma patients. Risk factors: High-speed collisions, falls, sports injuries. Mortality: 5–10% in hemodynamically unstable patients.

2.2 Cardiac Tumors¶

Primary tumors: 0.03% of autopsies. Metastatic tumors: 1–2% of cancer patients. Survival: 40% for primary lymphoma; <10% for most metastatic tumors.

3. ETIOLOGY & PATHOPHYSIOLOGY¶

Blunt injury causes myocardial contusion via mechanical stress, while penetrating injuries lead to direct tissue damage. Metastatic tumors spread via hematogenous or lymphatic routes. Cardiac rupture occurs due to progressive tissue necrosis or sudden pressure changes.

3.1 Blunt Injury Mechanisms¶

Rapid deceleration causes myocardial stretching, coronary artery dissection, or pericardial effusion. Myocardial contusion may mimic myocardial infarction with troponin elevation.

3.2 Penetrating Injury Pathophysiology¶

Direct trauma causes laceration, rupture, or tamponade. Gunshot wounds often involve multiple chambers, while stab wounds may target specific structures (e.g., RV).

3.3 Metastatic Tumor Spread¶

Hematogenous spread is most common. Sarcomas and hematologic malignancies have diffuse infiltration patterns, while carcinomas often form discrete nodules.

4. CLINICAL FEATURES¶

Blunt injury presents with chest pain, dyspnea, arrhythmias, or hemodynamic instability. Penetrating injuries may cause hemopericardium, cardiac tamponade, or sudden cardiac arrest. Metastatic tumors may present with dyspnea, syncope, or incidental findings.

4.1 Blunt Injury Symptoms¶

Chest pain (musculoskeletal or cardiac ischemia), dyspnea, arrhythmias, hypotension, and signs of pericardial tamponade (e.g., Beck’s triad).

4.2 Penetrating Injury Signs¶

Hemorrhagic shock, pulsatile bleeding from chest wounds, signs of cardiac tamponade, or sudden cardiac arrest.

4.3 Metastatic Tumor Presentation¶

Dyspnea, syncope, or incidental findings (e.g., pericardial effusion). May mimic myocarditis or cardiomyopathy.

5. DIFFERENTIAL DIAGNOSIS¶

Blunt injury must be differentiated from myocardial infarction, pulmonary embolism, or pulmonary contusion. Penetrating injuries require distinction from chest wall trauma or mediastinal hematoma. Metastatic tumors must be differentiated from primary cardiac neoplasms or inflammatory conditions.

5.1 Blunt Injury Mimics¶

Myocardial infarction (ECG changes), pulmonary embolism (hypoxia, elevated troponin), or pulmonary contusion (chest pain, hypoxia).

5.2 Penetrating Injury Mimics¶

Chest wall trauma, mediastinal hematoma, or esophageal injury (hematemesis, hemoptysis).

6. INVESTIGATIONS & DIAGNOSIS¶

ECG, troponin, chest X-ray, and echocardiography are first-line tests. Cardiac MRI and CT are used for detailed assessment. Pericardiocentesis confirms effusion, while biopsy or imaging identifies tumors.

6.1 Diagnostic Algorithms¶

Assess hemodynamic stability. 2. Perform ECG and troponin. 3. Use echocardiography for structural abnormalities. 4. CT/MRI for metastatic tumors. 5. Pericardiocentesis for effusion evaluation.

6.2 Imaging Modalities¶

Echocardiography: First-line for BCI. Cardiac MRI: Gold standard for tumors. CT: Detects metastases and anatomical details. Angiography: Evaluates coronary artery injury.

7. MANAGEMENT & TREATMENT¶

Blunt injury requires monitoring, resuscitation, and surgical intervention for complications. Penetrating injuries need immediate thoracotomy. Metastatic tumors are managed with palliative chemotherapy, radiation, or surgical drainage.

7.1 Blunt Injury Management¶

Stable patients: Monitor with ECG and troponin. Unstable patients: Immediate thoracotomy for pericardial tamponade or ventricular rupture.

7.2 Penetrating Injury Treatment¶

Emergency thoracotomy with repair of lacerations, tamponade, or cardiac rupture. Use of intraoperative echocardiography for guidance.

7.3 Metastatic Tumor Therapy¶

Palliative chemotherapy (e.g., bleomycin for lymphoma), pericardiocentesis for effusion, and surgical window for recurrent tamponade.

8. PROGNOSIS & COMPLICATIONS¶

Blunt injury mortality: 5–10% for stable patients, 90% for hemodynamic collapse. Penetrating injuries have 20–65% survival depending on injury type. Metastatic tumors have poor prognosis (<10% survival), with complications including tamponade, arrhythmias, and systemic embolism.

8.1 Blunt Injury Outcomes¶

Most patients recover with monitoring. Complications: Arrhythmias, heart failure, or pericardial effusion.

8.2 Penetrating Injury Mortality¶

Gunshot wounds: ~20% survival. Stab wounds: ~65% survival. Mortality correlates with multi-chamber injury and delayed resuscitation.

9. SPECIAL CONSIDERATIONS¶

Pregnancy: Increased risk of blunt injury due to uterine displacement. Pediatrics: Higher risk of commotio cordis from chest trauma. Elderly: Frailty increases mortality from both trauma and tumors.

Commotio cordis in adolescents from blunt chest trauma (e.g., baseball). Requires immediate defibrillation.

9.2 Palliative Care¶

Essential for metastatic tumors. Focus on symptom management and quality of life.

10. KEY POINTS & CLINICAL PEARLS¶

Blunt cardiac injury is often overlooked in trauma patients; ECG and troponin are critical for diagnosis. 2. Penetrating injuries require immediate surgical intervention. 3. Cardiac MRI is the best modality for metastatic tumors. 4. Pericardiocentesis is lifesaving for tamponade but temporary. 5. Commotio cordis is a unique pediatric risk from blunt trauma.