What is Blunt Cardiac Injury?
Blunt cardiac injury (BCI) is a range of heart conditions that can happen due to a forceful blow or injury to the chest. These injuries can range from a minor bruise to the heart muscle to a severe tear in the heart, which could be life-threatening. While only a few patients show abnormal heart test results or signs of shock (a sudden drop in blood flow), most have no immediate symptoms. Regardless, the possibility of sudden heart rhythm problems or failure of the heart to pump blood requires that BCI be considered in terms of appropriate monitoring and treatment.
The term “cardiac contusion” was previously used to describe these injuries to the heart after blunt chest trauma. Under a microscope, a cardiac contusion would be marked by a bruised heart muscle with blood cells infiltrating, localized areas of cell death, and swelling. These characteristics are mostly confirmed during surgery or an autopsy. However, the broader term “blunt cardiac trauma” has become preferred because it covers the full range of heart injuries that can result from blunt chest trauma.
According to a U.S. national registry of trauma data, between 2017 and 2021, only 14,219 out of 4.8 million patients with blunt trauma were diagnosed with BCI, amounting to just 0.3% overall. These injuries can be further defined by specific types or observed heart dysfunction. These injuries usually occur due to high-impact accidents, with car accidents accounting for 50% of cases, pedestrians being struck by vehicles making up 35% of cases, motorcycle accidents accounting for 9% and falls from considerable heights for 6%.
Diagnosing BCI is difficult due to the lack of agreed-upon diagnostic criteria and a definitive diagnostic test. It becomes even more challenging in patients with multiple injuries. The reported instances of heart injuries following blunt chest trauma range widely from 8% to 76% primarily due to absence of universally accepted diagnostic guide. In patients without severe heart rhythm problems and unstable blood pressure, there is sometimes debate about the importance of BCI. In the context of blunt trauma, a strong suspicion for BCI is needed, and certain patients should be monitored for any negative outcomes. Unfortunately, there are no specific clinical signs or symptoms backed up by evidence that are linked with the risk of heart complications. As a result, managing the possible outcomes is more important than what the condition is called.
What Causes Blunt Cardiac Injury?
Blunt cardiac injury (BCI), which is damage to the heart caused by forceful impact, often happens during car accidents, making up 50% of such cases. 1 in 5 deaths from car accidents involve this kind of chest injury. Other causes include falls, explosions, assaults, and other forms of hard impact. The type and amount of force determine how severe the heart injury is.
If the force is strong enough, it could squeeze the heart between the sternum (the center chest bone where your ribs connect) and spine. Or, during rapid deceleration (like a car crash), the heart could tear from its fixtures. Sadly, these types of injuries are usually so severe that those affected often don’t survive, and usually die at the scene.
Even though BCI may occur together with injuries to nearby areas like the aorta (the major blood vessel from the heart), lungs, ribs, sternum, and spine, these injuries don’t necessarily mean there’s a BCI. However, medical professionals should be extra cautious when treating patients with chest injuries.
Risk Factors and Frequency for Blunt Cardiac Injury
Trauma is the fourth leading cause of death in the United States. Estimating how often blunt cardiac injury (BCI) occurs can be difficult due to issues like the lack of a clear definition, inconsistent reporting, and not having widely agreed-upon methods of diagnosis. BCI can also often be misdiagnosed when it shares similar signs with diseases not related to it. For instance, if someone has an irregular heartbeat because of a different preexisting condition. Additionally, certain tests, like those used to measure the level of troponins (proteins that can indicate heart damage), can give misleading results because of injuries unrelated to the chest area.
The American Association for the Surgery of Trauma (AAST) created the AAST Cardiac Injury Scale, to categorize and grade the severity of both blunt and penetrating injuries of the heart. However, it is important for medical professionals to know that if a patient has numerous penetrating wounds in one heart chamber, or injuries in multiple heart chambers, the injury grade can increase.
Signs and Symptoms of Blunt Cardiac Injury
Recognizing trauma in someone with a blunted chest injury, especially due to force, is vital. For example, patients in car accidents need to share if they hit the steering wheel. In fact, a study showed that 54% of patients who fell more than 20 feet had such chest injuries. Common symptoms include chest pain, difficulty breathing, heart palpitations, or even chest pain similar to angina (a type of heart disease).
It’s important to assess heart disease risk factors, including a history of heart attack, heart disease, and other related health issues. It’s also crucial to know the patient’s medication history because some heart medications can change how the patient appears to a healthcare provider. For example, beta-blockers and calcium channel blockers can hide fast heartbeat.
A thorough physical exam should be conducted. In some cases, the patient might have a condition where fluid fills the sac around the heart (cardiac tamponade), and it should be suspected if they’ve neck vein swelling and low blood pressure. A special type of ultrasound exam called a “FAST” exam helps check for fluid around the heart and this condition. Some physical signs that should raise suspicion for a blunt chest injury include:
- Rapid, shallow breathing
- Abnormal lung sounds
- Tenderness in the chest
- Scratches or bruising on the chest
- Rib or breastbone fractures
- Seatbelt marks across the chest
Moreover, patients with severe blunt chest injuries are more likely to have other serious injuries, making it harder to detect the signs of the chest injury.
Testing for Blunt Cardiac Injury
There’s still no consensus on how to definitively diagnose blunt cardiac injuries (BCI), which are injuries to the heart caused by a blunt force, such as a car accident or a fall. However, in 2012, the Eastern Association of Trauma proposed some guidelines. They recommended that everyone suspected of having BCI should have an echocardiogram (ECG), a test that measures the electrical activity of the heart.
Patients with abnormal results should be hospitalized for continuous monitoring. But even a normal ECG doesn’t rule out BCI entirely, as there have been instances where patients who initially had a normal ECG showed signs of possible cardiac injury a day later, as indicated by increased levels of a heart muscle protein called cardiac troponin I (cTnI). However, patients who have both a normal ECG and normal cTnI levels are generally safe to be discharged from the hospital.
It’s important to note that even if both the ECG and cTnI levels are normal, BCI may still be there. Some BCI may appear later (like a septal injury, which is an injury to the wall separating the chambers of the heart).
The standard tests to diagnose BCI include ECG, echocardiography (a test using sound waves to create images of the heart), measuring cardiac biomarkers like troponin and creatine kinase (proteins that increase in the blood when the heart muscle is damaged), and finally radioisotope scanning, a technique that uses radioactive substances to visualize heart function. If the first ECG is normal, doctors suggest repeating it after 4 to 6 hours, along with the cardiac biomarker tests. More tests may be needed based on the results of these tests and the patient’s symptoms. But how exactly BCI is managed varies widely and usually depends on the specific protocols of the hospital.
While CT scans and MRI are not used initially to diagnose BCI, they can be useful if a patient continues to have symptoms without a clear cause and can be considered on a case-by-case basis.
FAST, or Focused Assessment with Sonography for Trauma, is a bedside ultrasound test used to check for circulation problems in trauma patients. It’s especially recommended for patients who are unstable after suffering blunt abdominal trauma or penetrating trauma where it’s unclear if the abdomen has been penetrated, and anyone with unexplained instability. The traditional FAST protocol checks 4 areas including the pericardium (to identify a condition where fluid builds up around the heart), the right upper quadrant, left upper quadrant, and pelvis (to detect blood accumulation in the abdomen).
The extended FAST (e-FAST) protocol also includes checking the spaces around the lungs for any signs of blood or air accumulation.
Treatment Options for Blunt Cardiac Injury
When a patient comes in with an injury, doctors follow a set of guidelines called the Advanced Trauma Life Support (ATLS) provided by the American College of Surgeons. These guidelines help physicians quickly assess and manage traumatic injuries. If the patient is in shock, doctors need to figure out what’s causing it. This is particularly important for patients with chest injuries, where heart-related issues are a common occurrence. In such cases, they use physical examinations, electrocardiogram (ECG – a test that measures the electrical activity of the heart), and an e-FAST test (a quick ultrasound examination) to identify serious conditions like fluid buildup around the heart and highly abnormal heart rhythms.
Patients with strange-looking ECG readings and high levels of a protein called cTnI (which is a sign of heart damage) should be admitted to the hospital. Doctors monitor them for 24 to 48 hours because severe irregular heartbeats (arrhythmias) or heart failure often occur during this window of time. These patients might be sent to the Intensive Care Unit or just monitored with technology called telemetry, depending on their other injuries, what their ECG looks like, and how off-balance their vital signs are (like heart rate and blood pressure). However, for all patients with chest bone (or sternal) fractures who have normal ECG findings, admission to the hospital is not necessary to rule out Blunt Cardiac Injury (BCI – damage to the heart from a blunt force). Most of the time, BCIs with only abnormal ECG or high cTnI levels are not severe and rarely lead to long-term heart problems.
Treatment of irregular heart rhythms in patients with BCI is similar to treatment in patients without BCI. Doctors manage it by adjusting electrolyte levels in the body, ensuring the patient gets enough oxygen and maintaining normal acidity levels, and if needed, giving medicines that control heart rhythms and perform life-saving procedures. Occasionally, some very specific situations like complete heart block may require a pacemaker (device that helps regulate the heart’s rhythm). And if the heart damage appears to be causing chest pain (like from a heart attack), doctors may need to do a test called coronary angiography (procedure that uses dye and X-rays to see how blood is flowing in the coronary arteries).
Finally, patients with severe injuries to the heart’s structure, as detected using medical imaging or clinical signs, need immediate evaluation from a cardiologist (heart specialist) for further treatment. While waiting for such evaluation, fluid transfusion and certain types of medications may be needed to keep their heart functioning. Urgent surgery is required for patients with cardiac tamponade, a dangerous condition where fluid builds up around the heart, most often encountered in heart rupture cases. In the majority of these cases, the speed in which heart surgery is performed is critical. For those unresponsive to typical treatments for cardiogenic shock (a severe heart condition that can’t supply enough blood to the rest of the body), a device called an intra-aortic balloon pump may be used. This pump helps increase the flow of blood to the heart, allowing it to recover over days to weeks.
What else can Blunt Cardiac Injury be?
When assessing someone for a blunt cardiac injury, doctors should also consider the following potential diagnoses:
- Arrhythmia (irregular heart rhythm)
- Cardiac tamponade (pressure on the heart caused by excess fluid)
- Cardiac wall motion abnormality (problems with the movement of the heart wall)
- Cardiogenic pulmonary edema (fluid buildup in the lungs due to heart problems)
- Cardiogenic shock (a serious condition where your heart can’t pump enough blood to your body)
- Hemorrhagic shock (a life-threatening condition that occurs due to massive blood loss)
- Myocardial infarction (heart attack)
- Valvular regurgitation (backward flow of blood due to faulty heart valves)
What to expect with Blunt Cardiac Injury
The outcome of Blunt Cardiac Injury (BCI), which is an injury to the heart caused by a blunt force, depends on several factors. These factors include the specifics of the injury, any associated injuries, and any previous history of heart disease or injury. A patient with a BCI revealed through an abnormal ECG (a test that measures the electrical activity of the heart) or a cTnI level (a blood test that checks for damage to the heart) tends to fare better compared to a patient who comes in with a severe, even life-threatening, condition due to a structural injury to the heart that also involves a high trauma injury score.
Mostly, patients with BCI tend to have a good outcome since they mostly fall into the first category. One research study compared two groups of patients 12 months after they had a blunt chest injury. One group had experienced a myocardial contusion (bruise or damage to the heart muscle), and the other had a blunt chest trauma without a myocardial contusion. The study showed no significant differences in ECG results or the functioning of the right and left ventricles (lower chambers) of the heart in both groups.
Another study followed patients with blunt thoracic trauma at 3 and 12 months after their injury. Among the patients who suffered a myocardial contusion and abnormal heart wall motions, 10 out of 17 still showed heart wall motion abnormalities at 3 months, and 4 out of 17 at 12 months. However, none of the patients showed abnormalities in the ECG during exercise testing, and none experienced limitations related to heart conditions during follow-ups.
Possible Complications When Diagnosed with Blunt Cardiac Injury
In general, complications from blunt cardiac injuries (BCI) are quite rare. Should they occur, particularly severe cardiac injuries, immediate treatment is required. Even after successful treatment, some patients might experience long-lasting impacts of their specific injury. Despite this, most patients with BCI do not suffer from long-term consequences. Nonetheless, some delayed complications have been reported such as delayed tearing of the heart, complete blockage of the pathway between heart chambers, heart failure, fluid in the heart sac, and constriction of the heart due to inflammation of the heart sac. For this reason, it’s highly recommended that patients suffering from BCI should undergo routine check-ups every three to six months.
List of Potential Complications:
- Severe cardiac injuries
- Delayed tearing of the heart
- Complete blockage of the pathway between heart chambers
- Heart failure
- Fluid in the heart sac
- Constriction of the heart due to inflammation of the heart sac
Preventing Blunt Cardiac Injury
The long-term outcomes for patients who’ve suffered a blunt force injury to the heart tend to be very good once they’re discharged. However, it’s essential for these patients to come back to the hospital or clinic for a follow-up check 3 to 6 months after the original injury. This revisit will allow doctors to reevaluate for any lingering signs of heart damage or irregular heartbeats (dysrhythmia).
