Hello, I'm Joseph Alpert, and we're going to be speaking now about cardiac trauma.
So, all regions of the heart can be injured when an individual suffers bodily trauma of any kind -
gunshot, stabbing, car accident, and so forth. Often the cardiac injuries are overlooked
because there are other serious injuries that are taking all the attention
such as bones sticking through the skin and so forth.
Some of them can be rapidly fatal for example laceration
or rapture of one of the cardiac chambers leads to very severe
and rapid cardiac tamponade and often the patient dies.
The trauma can be penetrating, gunshot, knife wound or non-penetrating trauma
for example, motor vehicle accidents or falls.
Myocardial rapture, contusion and laceration account for 90% of the cardiac traumatic injuries
and we're gonna talk about these each in place.
First of all, let's talk about injuries in the pericardium.
There can be laceration or rupture causing hemopericardium and tamponade
and there can be late onset autoimmune pericarditis from the traumatic injury to the pericardium,
this can also occur by the way after cardiac surgery.
In the myocardium, one can have a contusion, a laceration, or a rupture.
Healing of the laceration or controlled rupture can lead to late aneurysm formation, heart failure,
and embolism of blood clot out of the heart to the rest of the body.
The valves can tear with resultant regurgitation or the coronary arteries can be lacerated
or thrombosed that is plugged with resultant myocardial infarction.
The conduction system can be interrupted leading to heart block
requiring a pacemaker and the great vessels can rupture or be lacerated
that is the aorta and the pulmonary artery.
Here's an example with a little cartoon of a blunt traumatic injury to the sternum
and subsequently to the right ventricle which lies just beneath the sternum.
So what happens in terms of changes on the physical exam?
Often, when a patient comes in with trauma the physical exam is relatively quick
because you gotta get the patient into the operating room
so some of these findings might not be immediately evident.
Certainly, most patients are gonna be tachycardic, they may have tamponade
from injury to the myocardium or the pericardium with blood collection under the pericardium.
You may have marked bradycardia because of a damage to the conduction system.
The patients are often hypotensive because of hemorrhage
but it could also be because of tamponade,
if there was an injury to the pericardium or the myocardium resulting in blood in the pericardial space.
There could be signs of heart failure with the jugular venous distention,
lung crackles and the third heart sound telling you that either the right or left ventricle
has been seriously injured.
It's important that one remember that most commonly,
the right ventricle is the injured ventricle because it’s the most anterior one right beneath the sternum
so it’s gonna be the first one to take blunt or penetrating trauma.
As mentioned, the ventricle right behind the sternum is the right,
it’s trauma to the sternum gets transmitted right away to the right ventricle thereby injuring it.
In the case of right ventricular injury, sometimes you can tear or injure the tricuspid valve
and you may hear a regurgitating murmur of tricuspid regurgitation sort of -- over the sternum.
One can hear a pericardial rub, if there's been a contusion or laceration of the pericardium
and that rub sounds something like this -
you can hear almost a crunching sound if there's a pericardial rub you need an Echo
of course to look for fluid in the pericardial space.
The EKG often shows non-specific ST-T changes with contusion.
Sometimes there’ll be a bundle branch block pattern or even more serious heart block
and there can be atrial or ventricular arrhythmias.
Blood loss often results in anemia and that’s usually due to injury in other areas,
and of course there's often an elevated blood troponin if there's been a myocardial injury or ischemia,
of course the body takes other traumatic injuries so there could be elevated muscle
and liver enzymes from other parts of the body that had been injured.
If one doe an Echo, you may see decreased myocardial contractility with a contusion
for example with the right ventricular contusion or pericardial effusion,
with or without tamponade following chest trauma that results in an injury to the right ventricle and the pericardium.
Therapy - we monitor the electrocardiogram continuously for arrhythmias.
We monitor the troponin values in a semi-quantive estimate
of how much volume of injured myocardium there is.
The higher the troponin goes, the worst the prognosis of course.
Arrythmias are treated either with beta blockade or with specific antiarrhythmic agents.
If they're heart block, of course, the heart block may require pacing.
And if there's tamponade often pericardial synthesis has to done with drainage of blood from the pericardial space.
The delayed autoimmune pericarditis is much more benign
and usually treated with non-steroidal anti-inflammatory agents such as ibuprofen as well as colchicine.
In a heart failure, there may be a need for intravenous catechol support if it’s severe or diuretics
if there's pulmonary congestion.
And of course, severe injuries may require surgical repair by CT surgery.