Blunt cardiac injury (BCI) occurs when extreme external trauma to the chest region results in internal injuries. It does not often leave any external wounds or marks, unlike penetrative cardiac injury. Blunt cardiac injury affects the functioning of cardiac valves and hampers blood circulation in the body. It is also commonly often referred to as cardiac concussion and is often the reason why people succumb to internal heart injuries either immediately or a couple of hours after the accident.
Dr Ranjan Shetty, HOD and consultant, interventional cardiology, Manipal Hospital, Bengaluru, says that the heart is usually protected as it is situated inside the rib cage and a part of it is covered by lungs. “But this protection is not absolute, especially for the right ventricle as it is located behind the sternum and slightly towards the left side,” points out Dr Shetty.
What causes blunt cardiac injury?
The main causes of blunt cardiac injury are motor vehicle accidents, sports injuries and physical assault. Dr Sreekanth B Shetty, senior consultant and head, interventional cardiology, Sakra World Hospital, Bengaluru, cites an example of blunt cardiac injury. He says, “If someone has a head-on collision while driving a car, and the chest comes in contact with the steering wheel, it can cause blunt cardiac injury. That is the most typical example, as opposed to penetrative cardiac injury, where someone is stabbed, say with a knife in the heart.”
What happens when there is blunt chest trauma?
It can affect the heart in multiple ways. The injuries could range from arrhythmias to valve rupture. Dr Ranjan explains, “It could lead to some contusion [bleeding in the muscle] in the right ventricle, which in turn causes arrhythmias [irregular heartbeats]. Another thing that can happen is the tearing of the tricuspid valve [between the right atrium and right ventricle]. If there is a valve injury, it could lead to the rushing back of blood instead of blood flowing forward.”
Dr Sreekanth adds that a direct blow to the heart can cause pericardial contusion (bruising of the heart). “Depending on the extent of injury, it can cause arrhythmias as it can trigger electrical instability in the heart. This might be diagnosed by imaging or MRI or it might be diagnosed after the person is dead during the autopsy,” he says. There could be injuries to the blood vessels, leading to coronary artery dissection or tearing in the coronary artery wall, causing a heart attack. “It may cause aortic dissection, which can cause stress on the aorta, leading to severe chest pain, paralysis, fainting, high heart rate and low BP. It requires surgical corrections then. It may also damage the internal parts of the heart by tearing the ventricular septum or rupturing the free wall of the heart, which can cause hemopericardium [collection of blood in the pericardial sac] and then tamponade [compression of the heart due to the accumulation],” he adds.
Blunt cardiac injury in trauma
At the site of the accident, it is very important to look for potential signs of blunt cardiac injury. There may be no visible signs to examine. “Their heart will sound distant. The blood pressure will be low and the pulse will be rapid. The jugular venous pressure [an indirect measure of the vascular pressure in the vein or atria of the heart] will be elevated. These could be signs of blunt cardiac injury, which can be diagnosed by only a doctor,” he says.
Blunt cardiac injury treatment
If the injury causes cardiac tamponade, it can lead to immediate death. “Aortic dissection can be fatal too unless it is immediately recognised and treated. Heart arrhythmias need to be picked up and treated. If there is a free wall rupture, it is fatal. If it is septal rupture, it has to be surgically corrected,” he says, adding that if the person has an extensive contusion of the heart, it can cause congestive heart failure, which can require the implantation of a defibrillator (a device to restore normal heartbeat) and frequent hospital visits, affecting the quality of life of the person.
Blunt cardiac injury is not common. But because of the absence of external wounds, it is often missed initially leading to serious complications. “In road traffic accident cases, polytrauma [injuries to multiple body parts] is mostly observed. Because of the nature of injury [like road accidents and sports injuries], it is more common among teenagers,” says Dr Ranjan. But the ability to tolerate the injury may be low among older people.
According to a recent study, published in the Journal of Trauma and Injury, non-survivors mainly had atrial and ventricular injuries, of which half were left ventricular.
Dr Raghavendra R, associate professor, department of forensic medicine, St John’s Hospital, Bengaluru, says, “When we do an autopsy, the obvious cardiac issue we see is ventricular fibrillation [irregular heart rhythm in the lower chambers of the heart] due to blunt trauma to the chest. The heart rate goes up to 300 and even 350 beats. There aren’t any visible external injuries most time. The death could have occurred due to vagal inhibition [sudden death due to pressure on the vagus nerve in the neck] with trauma near the lower part of the chest.”
What are some of the possible consequences of a blunt injury to the heart?
Dr Raghavendra points out that the majority of deaths in road accidents in India are also due to polytrauma or among people who already have an underlying heart condition. He also adds that the blunt cardiac injury could be an add-on factor that leads to critical cardiac complications.
“The blunt injury can precipitate and can make the already existing cardiac problem worse, especially in the elderly. It can lead to ventricular rupture if the person has a cardiac pathology like an atheroma clot [clot in the arteries which can lead to a heart attack]. If a person has hypertrophic cardiomyopathy [when heart muscles get thicker, increasing the weight of the organ from about 250/300 grams to 400/500 grams] and is not aware of the condition, he may lose consciousness and die in case of a blunt cardiac injury shock,” he says.
Dr Ranjan says if there is an injury in the chest area, it is important to get it evaluated for any direct damage to the heart. “In acute cases, if there is valve damage, it can be problematic. It can affect the blood flow to the rest of the body. It is one of the reasons why sportsmen die suddenly on the field,” he says. Other injuries can be corrected and can heal like any other muscle injury, but this might not happen in the case of a severe blow to the chest.