Cardiac injury

Background

• Spectrum of disease due to blunt trauma to the chest wall - ranges from mild contusion to cardiac rupture and death.

Clinical Presentation

Penetrating Trauma

• Location
  • Stab wounds
    • Usually affect heart if enter via the "cardiac box"
      • Chest area bounded by sternal notch, xiphoid, and nipple
  • GSW can affect heart even if enters at distant site
• Ventricles are at greatest risk due to anterior location
  • RV (involved in 40% of injuries)
  • LV (involved in 35% of injuries)
  • RA (involved in 20% of injuries)
  • LA (involved in 5% of injuries)
• Cardiac tamponade
  • Most often results from stab wounds; up to 80% of myocardial stab wounds may develop cardiac tamponade
  • GSW less likely to develop into tamponade because it is more difficult for the pericardium to seal the defect (larger, more irregular in shape)
• Cardiac missiles
  • Those that cause BP instability, free or partially exposed should be removed
  • Most intramyocardial and intrapericadrial bullets can be left in place

Blunt Trauma

• Up to 20% of all MVC deaths are due to blunt cardiac injury
• Most often involves the right heart (due to ant location)
  • Injury to valves occurs in 10%
• May present as:
  • MI (coronary artery injury)
  • Acute heart failure (valve rupture)
  • Dysrhythmias
• Commotio Cordis
  • Primary electrical event resulting in the induction of Vfib
  • Often an innocent-appearing blow to chest wall

Differential Diagnosis

Thoracic Trauma

• Airway/Pulmonary
  • Bronchial injury
  • Diaphragmatic trauma
  • Hemothorax
  • Pneumomediastinum
  • Pulmonary contusion
  • Tracheal injury
  • Trachobronchial injury
  • Traumatic pneumothorax
    • Tension pneumothorax
• Cardiac/Vascular
  • Cardiac injury
    • Blunt cardiac injury
      • Cardiac contusion
      • Commotio cordis
    • Penetrating cardiac injury
    • Cardiac tamponade
  • Traumatic aortic transection
• Musculoskeletal
  • Clavicle fracture
    • Clavicle fracture (peds)
  • Rib fracture
    • Flail chest
  • Scapular fracture
  • Scapulothoracic dissociation
  • Sternoclavicular dislocation
  • Sternum fracture
  • Thoracic and lumbar fractures and dislocations
• Other
  • Esophageal injury or Perforation
  • Pneumomediastinum
  • Pneumopericardium
  • Traumatic asphyxia

Diagnosis

• CXR
  • Mediastinum widening is only suggestive of an aortic injury
    • Lack of widening does not rule out aortic injury
• CTA
  • Imaging study of choice for penetrating and blunt trauma
• Ultrasound: FAST
  • First view of FAST in penetrating injury should be pericardial
  • Pericardial fluid detection (Sn 100%, Sp 97%)
• ECG
  • NPV for a normal ECG is 80-90%
  • Not as sensitive for right-sided injuries
• Troponin
  • Trend in all patients
  • Combination of normal ECG and normal troponin 100% sn in one study

Management

Penetrating Trauma

• Thoracotomy
• Pericardiocentesis

Blunt Trauma

• Observe all patients with cont cardiac monitoring and interval assessment of cardiac markers

Great Vessels Injury

Aorta

• Proximal descending aorta is most commonly injured in blunt trauma
  • Due to fixation of vessels between L subclavian artery and ligamentum arteriosum
• Most patients die at the scene
• Control of BP and HR is important if operative management will be delayed

Subclavian

• Usually due to direct trauma or fracture of first rib or clavicle
• Loose shoulder restraint

IVC/SVC

• Suspect if major hepatic injury or patient has bleeding that cannot be identified

See Also

• Thoracic Trauma
• Commotio Cordis