Blunt cardiac injury (BCI), formerly called myocardial contusion, encompasses a spectrum of disease ranging from histologic injury to the myocardium without clinical manifestation to blunt cardiac rupture.1 BCI contributes to 20% of prehospital deaths from blunt trauma.2 An exact incidence of BCI does not exist because there is no “gold standard” for diagnosis, i.e., the available data are conflicting with regard to how the diagnosis should be made (ECG, echocardiography, enzyme analysis, etc.). This lack of a diagnostic standard makes the literature difficult to interpret and leads to confusion in clinical practice.
The major priority is identification of patients at risk for adverse events resulting from BCI and providing appropriate workup, monitoring and treatment. Patients with any significant blunt trauma to the anterior chest should be screened. Conversely, patients not at risk can potentially be discharged home. Patients with appropriate mechanism of injury and clinical evidence of cardiac dysfunction (electrophysiological or mechanical) can be considered to have BCI.
BCI results from 5 possible mechanisms: direct pre-cordial impact, crush between sternum and spine, deceleration or torsion causing a tear in the heart at a point of fixation, hydraulic effect resulting in rupture from elevated intra-abdominal and caval pressure, and blast injury.3 Few clinical signs are diagnostic of BCI. Chest pain is the most common finding. Dyspnea, palpitations, chest wall ecchymosis, murmur or rub, muffled heart sounds, subcutaneous emphysema and rib fractures may also be present. Associated injuries include hemothorax, sternal fracture and great vessel injury. Clinical signs consistent with BCI include dysrhythmias, cardiac ischemia, low cardiac output and hypotension.4
Diagnostic tests include ECG, echocardiography, and troponin analysis. Controversy exists regarding the application of these tests. Frequency of diagnosis of BCI will be proportional to the aggressiveness with which it is sought. Appropriate workup commands achieving a balance between cost-effectiveness and information acquisition with attention to the clinical value of information gained in changing patient management. Guidelines for using diagnostic tests are as follows:
Level 1
An admission ECG should be performed on all patients in whom BCI is suspected. Using any ECG abnormality, including sinus tachycardia, bradycardia, conduction delays, and PAC’s/PVC’s, the diagnostic sensitivity of ECG is 100%.6
Level 2
A. If the admission ECG reveals a new abnormality (arrhythmia, ST changes, ischemia, heart block, and unexplained ST changes), the patient should be admitted for continuous ECG monitoring. For patients with preexisting abnormalities, comparison should be made to a previous ECG to determine need for monitoring.
B. In patients with a normal ECG result and normal troponin I level, BCI is ruled out. Patients with normal ECG but elevated troponin should be admitted to a monitored setting.
C. For patients with hemodynamic instability or persistent new arrhythmia, an echocardiogram should be obtained. If transthoracic echo cannot be performed, the patient should have a trans esophageal echo.
D. The presence of a sternal fracture alone does not predict the presence of BCI and should not prompt monitoring in the setting of a normal ECG and troponin.
E. CPK with isoenzyme analysis should not be performed because it is not useful in predicting which patients have or will have complications related to BCI.
F. Nuclear medicine studies add little when compared with ECG and should not be routinely performed.
Level 3
A. Elderly patients with known cardiac disease, unstable patients, and those with an abnormal admission ECG can safely undergo surgery provided that they are appropriately monitored. Consider placement of a pulmonary artery catheter in such cases.
B. Troponin should be measured routinely for patients with suspected BCI. If elevated, patients should be admitted to a monitored setting and troponin should be followed serially.
C. CT or MRI can be used to help differentiate acute myocardial infarction from BCI in trauma patients with abnormal ECG, cardiac enzymes, and/or abnormal echo to determine need for cardiac catheterization and/or anticoagulation.
References:
2. Schultz JM, Trunkey DD. Blunt cardiac injury. Crit Care Clin 2004;20:57-70.
5. Pasquale NK, Clarke J. Screening of blunt cardiac injury.1998. The Eastern Association for the Surgery of Trauma. Available: http://www.east.org/tpg/chap2.pdf
7. Karalis DG, Victor MF, Davis GA, McAllister MP, Covalesky VA, Ross Jr JJ, et al. The role of echocardiography in blunt chest trauma: a transthoracic and transesophageal echocardiographic study. J Trauma 1994;36(1):53-8.
9. Salim A, Velmahos GC, Jindal A, Chan L, Vassiliu P, Belzberg H, et al. Clinically significant blunt cardiac trauma: role of serum Troponin levels combined with electrocardiographic findings. J Trauma 2001;50(2):237-43.
11. Clancy, K., Velopulos, C., Bilaniuk, J., Collier, B., Crowley, W., Kurek, S…Haut, E. (2012). Screening for blunt cardiac injury. Journal Trauma 73 (5): S301-S306.
Revised: 01/13
