By: John A. Filip, MD

There are more than 6 million auto accidents each year in the United States with 3 million people inured and 2 million experiencing permanent injuries. Undiagnosed myocardial contusion injuries (MCI) in the emergency department after blunt thoracic trauma (BTT) in MVAs is a serious and life threatening situation.

Myocardial Contusion Injury

An MCI is a bruise of the heart muscle, which can occur with serious bodily injury. It is most commonly caused by a car accident, but can also occur in falling from heights greater than 20 feet, and by receiving chest compressions during cardiopulmonary resuscitation (CPR). It is more likely to occur from injuries resulting in accidents related to a sudden decrease in vehicle speed (a deceleration injury).
The severity of MCI can vary depending on the severity of the injury and when the injury occurs. It is a common cause of rapid death which happens after BTT and should be suspected at triage in the ED.
The suspected MCI patients who have normal electrocardiograms and biomarker tests can be safely discharged home. However, if the tests results are abnormal or the patient was in a severe car accident, the next steps should be echocardiography and more advanced measures. Diagnosing MCI is very difficult because of it’s nonspecific symptoms. If MCI happens, cardiogenic shock or arrhythmia must be anticipated, and the patient carefully monitored.
MCI should not be confused with infarction. Myocardial infarction, occurs when the heart is severely damaged as a result of a lack of blood flow to the muscle.

Evaluation of patients with BTT
Diagnosing MCI can be difficult due to the patient’s nonspecific symptoms and the lack of ideal diagnostic test. Strong suspicion is required to diagnose MCI.
When ED physician suspects that severity of chest trauma may cause MCI, there are several methods available for its detection, such as electrocardiography, echocardiography, nuclear cardiac imaging, and heart biomarkers. None of these tests are 100% sensitive. The only conclusive test is autopsy.
Today, the best method to assess myocardial viability is PET scan with fluorine-18 (18F-FDG), although it is not recommended for routine use.
An algorithm for detection of MCI in BTT patients is available in the literature (3).

Case Example

A 77-year-old retired female was the driver of Honda Accord involved in a T-boned car accident with a large PECO truck. Her car was totaled. The airbags exploded, with the front one cutting her lip. She complained of pain in multiple areas of her body, including severe pain in the left clavicle, both knees and the right ring finger. The patient denied any chest pain, loss of consciousness, or back pain. Medical background included diabetes mellitus, hypertension, hyperlipidemia and hyperthyroidism.

In the ED, she had X-rays and blood troponin I level. Troponin I level, was normal. She was admitted for a 3-day hospital observation and discharged home to follow up with physical therapy and orthopedic care.
3 weeks later, while receiving physical therapy she suddenly developed dizziness, garbled speech and difficulty finding words.
In the ED, she had severe dysarthria and aphasia.
She was diagnosed with a stroke and treated with an IV anticoagulant, tPA, with the resolution of her symptoms.
EKG demonstrated atrial fibrillation(AF). Cardiology evaluation and holter monitor revealed intermittent atrial fibrillation which was not present prior to the car accident.
The patient was prescribed an anticoagulant, Xarelto 20 mg and to prevent recurrence of atrial fibrillation, Toprol 50 mg daily.

Errors made in the care of the described patient

    1. The attention of the physician was directed to the painful areas in extremities ignoring evaluation of the heart. The patient was in a serious car accident. Her car was totaled; air bags were inflated. She was an older individual with the history of diabetes, hyperlipidemia, hypertension, heart failure and thyroid disease. Even the symptomless patient may have MCI. There was a likelihood she had BTT and was prone to develop MCI, arrhythmia and other cardiac complications. Careful history and physical evaluation of the heart and chest should be done to exclude MCI.
    2. EKG was not done on admission. It is one of the important screening tests to be performed in the ED.
    3. Troponin I level was normal, but the test should be repeated in 4-6 hours as necessary for exclusion of myocardial damage. In addition, CPK enzymes should be obtained.
    4. Cardiology consultation was not requested on admission. Specialist could suggest in this patient’s setting additional tests in addition to EKG, like echocardiogram, cardiac monitor etc.
    5. On admission, this patient was not aware of chest pain. However, the patient who is in shock, has unstable cardiovascular condition, is confused, disoriented or anxious therefore may not be capable to communicate clearly heart related symptoms like chest pain or heaviness, shortness of breath or palpitation. Close cardiac monitoring for any new onset of arrhythmia should be done in CCU or ICU for at least 72 hours.
    6. At the time of discharge from the hospital follow up with cardiologist should be arranged. This was not done in this case.


Missed diagnosis of myocardial contusion

ED physicians need to be vigilant in evaluation of patients with severe BTT patients with multiple rib fractures, simultaneous pulmonary contusion, hemothorax and intrathoracic vascular injury. Patients with these conditions have a 13% chance of blunt MCI. They may also experience pain such as angina and infarct that is not reduced with analgesics. Patients may have shortness of breath, flail chest, chest wall tenderness, arrhythmias, ectopic beats and sinus tachycardia.
Any new abnormalities in cardiac evaluation not explained by otherwise obvious causes like coronary heart disease, pericardial effusion, or penetrating heart wounds should be considered as related to MCI.
Ignoring patients’ symptoms, poor physical examination, or not ordering required diagnostic tests may result in missing the diagnosis of MCI, and unnecessary death.

Conclusion
Diagnosis of MCI needs to be considered in any patient in with BTT, involved in a serious car accident, who has background of heart related conditions, especially with an abnormal EKG or elevated troponin I or T levels on admission.
Prompt recognition and treatment of the patient with MCI can reduce morbidity and mortality in car accident victim with BTT.
ED physician needs to be qualified and vigilant to recognize MCI condition.

Further reading:

      1. Diagnosing cardiac contusion: old wisdom and new insights. Heart 2003, May; 89(5): 485-489.
      2. Myocardial contusion: emergency investigation and diagnosis. Emergency Medicine Journal, 19/1/2008. Pp: 1-9.
      3. Diagnosis Myocardial Contusion after Blunt Chest Trauma.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027160/

About the Author
John A. Filip, MD is a cardiology trained physician with wide medical legal experience in trauma, motor vehicle accidents and undiagnosed myocardial contusion injuries. He can be reached at (610) 659-7960 or johnfilip@mac.com.