Pericardium and Extra-Cardiac Structures: Anatomy and Pathology

Published on 06/02/2015 by admin

Filed under Anesthesiology

Last modified 06/02/2015

Print this page

This article have been viewed 1853 times

Pericardium and Extra-Cardiac Structures

Anatomy and Pathology

Enrique Pantin and F. Luke Aldo

There are so many things surrounding the heart that no one pays attention to!

It is all about the heart though, so who cares about all that other stuff. Right? Wrong!

Like a lot of things in life, we forget that it is not about the “prima donna”, but about the team! After all, there is no “I” in team, but wait a second, there is a “ME”. Alright, never mind, let’s move on!

The Pericardium

Surrounds, protects, supports, limits chamber dilation, and lubricates, allowing the free motion of the heart.

Provides entry and exit passages to the heart.

Is a medium-sized bag with lots of holes and tubes crossing it to enter or exit the heart:

superior vena cava (“A”)

aortic root (“B”)

main pulmonary artery (“C”)

pulmonary veins (right “D” and left “E”)

inferior vena cava (“F”)

The aortic root (“B” in the image above) is one of the structures the pericardium covers, so if the root decides to rupture, well that patient is so out of luck… cold and dead! As in ruptured aortic root dissection with exsanguination into the pericardial sac→pericardial tamponade→that light at the end of the tunnel…

There is a club composed by the “extra-cardiac structures team” whose members can be seen by TEE most of the time but they are not too happy with the lack of credit. Everybody talks about the heart, but what about us?

Ascending aorta.

Aortic arch and its branches.

Descending thoracic aorta.

Upper abdominal aorta and its branches.

Internal jugular veins.

Innominate vein.

Trachea (yeah, we know you can’t see me but you know where I am because I don’t let you see other guys!).

Lungs, and pleural cavities.

Thymus (in children).

Spine, vertebral disks, and spinal cord (just bits of it can be seen).

Stomach and its content or lack of it.

Other stuff like the tongue could be seen but it won’t be TEE but oral ultrasound!

These are all members of the “extra-cardiac structures team”, they are the majority, but this still sounds like a dictatorship by that narcissistic heart!

As the TEE probe is advanced through the esophagus and into the stomach we can image several structures besides the heart.

Starting from the esophageal entrance we can see the main neck vessels (the carotid arteries and internal jugular veins)

can be used to guide central line placement, though I would NOT recommend this in the awake patient!

In the esophageal upper 1/3, we can see part or all of the arch vessels

almost always the left subclavian, and sometimes the others

distal aortic arch

innominate vein

left and right upper lung and pleural spaces

In the mid 1/3 of the esophagus, the trachea creates a blind spot, and we miss the distal ascending aorta, proximal arch, and proximal to mid left pulmonary artery, but we can see:

ascending aorta

main pulmonary artery

right pulmonary artery

sometimes part of the left pulmonary artery

proximal and mid thoracic aorta

right upper pulmonary vein

transverse sinus

left and right mid lung and pleural spaces

In the lower 1/3 of the esophagus, we can see:

pulmonary veins

distal thoracic aorta

left and right lower lungs and pleural spaces

From the transgastric window we can see:

stomach and its contents

upper abdominal aorta

often the celiac trunk, SMA, spleen, and kidneys as well

Because the esophagus, our magic TEE window, is all the way in the back of the chest, we decided to do a drawing from the esophageal perspective. Then we took the back of our drawing away, including the spine and rest of the bones, and applied some crude “X-ray” views to see what lies in front of it. This is probably the only time the esophagus finished first in a coronal view anatomical race. Congratulations Mr. “E”!

trachea and lungs are gray

stomach and esophagus are dotted gray/black

rest of the structures are black

L = left and R = right; PA = pulmonary artery, P = pulmonary veins, H = heart, L = liver, S = spleen, and K = kidney.

Did you understand the drawing?, I didn’t… If you didn’t, don’t kill yourself over it, it is a pretty bad drawing. My partner did the drawing, so call him and let him know you are happy he is a doctor and not an artist!

If you understood it, you are a genius!… then skip the following sentence. If you did not understand it, then continue reading and do as you are told. Go to your anatomy book and do a little review. Now pretend you are the esophagus and try to imagine how all of your neighbors look from where you are.

How can we see fluid on TEE?

All potential spaces in the chest and abdomen (pericardial, pleural, abdominal, sub-diaphragmatic, and hepato-renal) have the potential for fluid accumulation.

Depending on the location, amount, and speed of accumulation, it can present as a clinically silent finding on TEE or it can cause hemodynamic compromise.

Fluid is usually seen as black on echo, but if the fluid has solidified, as in the case of clotted blood, it can look just as the liver or lung atelectasis does!

In a transgastric mid-short-axis view below, we can see lots of stuff besides the heart!

Gastric lining at the top, note the gastric rugae (those very tiny indentations in the very top of the echo image).

Left lobe of the liver (L).

Pericardial reflection (that white line between “L” and the heart).

Moderate-sized focal image “C”, suggestive of clotted blood:

almost looks like liver does

looks very similar to a layer of epicardial fat and can trick even the experts!

the history and additional findings will help define what the heck this is.

Right (R) and left (LV) ventricular cavities.

Distal to the heart is more pericardium and lung.

There are very few important questions about the extra cardiac structures in the fast-paced world of anesthesiology and acute care. Usually questions include:

“Is there a pericardial effusion or not?” and if there is,

“is it tamponade or not?”

“Is there an aortic dissection?”

“Is there a transection?”

“Is there an aneurysm?”

“Is there a clot in the pulmonary artery or other evidence of a pulmonary embolism?”

“Is there a pleural effusion?”

The rest is by far secondary, technicalities we really don’t care too much about! After all, we are here to diagnose cardiac abnormalities and things that can immediately affect cardiac function, not to determine if the patient had filet mignon or penne a la vodka for dinner last night!

The Pericardium—we are back here again!

Is 1–2 mm thick.

Is difficult to see by echo unless there is fluid on both sides of it or it is very thickened.

Can elicit some extra brightness on echo like it has its own light.

Has two layers (fibrous and serous).

Serous layer has visceral and parietal aspects:

serous parietal layer is tightly bound to the fibrous pericardium that separates it from the rest of the chest structures

serous visceral pericardium is attached to the epicardium.

The layers extend a couple of centimeters, incorporating the aorta and main pulmonary artery.

Confines the total volume the heart can handle at one time creating a closed volume relationship among all cardiac chambers.

This limited volume relationship is the basis for the changes seen during effusions and restrictive or constrictive pericarditis.

There is normally a bit of pericardial fluid or “oil” (normally 5 to 10 ml and rarely up to 50 ml) that lubricates the heart so it can dance without causing too much noise. Just like a car engine needs motor oil, so does the engine of the human body. Luckily, we don’t need oil changes every 3000 miles!

When the oil is too thick because the sac gets inflamed (pericarditis) or if the sac gets stiff, the pericardial layers rub as the heart moves and make some weird noises.

When the oil level is too high, we call this a pericardial effusion.

Several types of “oil” can fill the pericardial space:

serum, sero-sanguineous fluid, blood, pus, solid things like metastatic tumors, fibrinous strands, etc.

Excess “oil” can be due to:

idiopathic causes, inflammation, infection, post heart attack, systemic conditions, malignancy, post trauma, surgery, radiation, congestive heart failure, etc.

Buy Membership for Anesthesiology Category to continue reading. Learn more here

Related

Board Stiff Tee Transesophageal Echocardiography 2e