Blunt Cardiac Injury (BCI) Pathophysiology - most often involves the right heart due to its anterior location
Management - if normal EKG but concern for BCI, monitor for 4 - 6 hours with repeat examinations, EKGs, cardiac monitoring - if abnormal EKG but no hemodynamic instability, admit to monitored setting EKG - NPV with normal EKG = 80 - 90% - more sensitive for LV than right-sided injury - nondiagnostic findings (e.g., nonspecific ST-T wave changes) do not aid in diagnosis of BCI
Cardiac Biomarkers - CK-MB has no value in traumatic injury - troponins may be elevated in all myocardial trauma - troponins can be used with EKG to risk-stratify patients - clinically significant BCI can occur without elevation of troponins, but usually have abnormal EKG
Echocardiography - POC ultrasound has been shown to have 100% sensitivity, 99% specificity for pericardial effusions - TTE or TEE has not been helpful in identifying patients at risk for developing BCI complications - should be ordered for patients with elevated cardiac markers, dysrhythmias, or myocardial dysfunction
Types of Injuries
Commotio Cordis - sudden arrest from blunt trauma to chest wall - primary electrical event causing ventricular fibrillation - no evidence of anatomic injury
Cardiac Dysfunction - decreased contractility - blunt injury to lung -> increased pulmonary vascular resistance -> reduction in preload of LV -> hypotension - RV with decreased cardiac output - management: monitor for dysrhythmias
Pericardial Injury - pericardial tears usually occur at the left of pericardium parallel to phrenic nerve and may be site of herniation - management: usually surgical unless tear is too large
Injury to Cardiac Valves, Papillary Muscles, Chordae Tendineae, and Septum - involvement of aortic valve > mitral and tricuspid valves - aortic valve injury -> widened pulse pressure, acute valvular insufficiency, cardiac failure - muscular septum can rupture several days after trauma - management: surgery
Injury to Coronary Vessels/Myocardial Infarction - rare - most commonly involves LAD - management: PCI with stenting - fibrinolytics are contraindicated, cautious use of anticoagulation
Cardiac Rupture - most die at the scene - right heart is more susceptible due to anterior location, thin-walled atrium - "splashing mill wheel"/"bruit de Moulin" murmur - EKG shows conduction defects, axis deviation - management: immediate thoracotomy
Resources Tintinalli's Emergency Medicine, 8th edition