Bruits vs Murmur

Double-Helix, BSN, RN · May 30, 2012

A murmur is just a word used to describe an abnormal sound caused by turbulent blood flow.

A bruit is a murmur that is heart in an artery or vein. A murmur, as it's typically used in the medical field, is an abnormal sound from the valves in the heart.

Think of a bruit as a "vascular murmur," not to be confused with a heart murmur.

DarkLotus · May 30, 2012

So both a bruits and a murmur are the sounds produced by turbulent blood flow. A murmur is auscultation of the turbulence within the heart. A bruit is heard outside of the in an artery or vein. Is the turbulence that causes the bruit within the vein or artery that it is heard in or is it the sound traveling through the vessel from the heart? (I need to see a video of this because no matter how much I read I'm still not getting it!)

Double-Helix, BSN, RN · May 30, 2012

It's a narrowing in the artery that causes the turbulent flow, producing the bruit. One of the more common ones that you'll hear is a carotid artery bruit- heard by placing the stethoscope over the carotid artery. If you google "carotid artery bruit" you'll find more information about it.

Esme12, ASN, BSN, RN · May 30, 2012

The murmur is cause by turbulent blood flow over the valve in the heart.

The bruit is the turbulent blood flow within the vessel itself. Whether it is from blockage, restriction malformation, or the vessel itself as in the AV fistula for renal dialysis.

DarkLotus · Jun 1, 2012

So despite thinking about this topic for a long time, on the quiz I was wrong.

The questions was:

What is abnormal blood flow within the heart usually referred to?

I answered turbulence.

I was wrong the answer is shunt.

I thought a shunt was specifically sideways looping of the blood before exiting the left atrium into the aorta not any abnormal blood flow.

Could someone please explain to me the pattern of thinking that should have lead me to the specific answer of shunt and not the general concept of turbulent blood flow?

Thanks!

Esme12, ASN, BSN, RN · Jun 1, 2012

Turbulence is the sound blood makes swirling around in a confined space like the carotid artery. the ballooning of an aneurysm, the fistula of a renal dialysis patient. The blood "swirls" in a circular motion. Visual example....when you flush the toilet. Or a leaky pipe.....a pipe a leak and the water slows and swirls in the pipe as some leaks out the side causing a constant noise.

A murmur is the shunting of blood through a weakened door/valve/wall/septum that is normally closed and sealed tight. The murmur is created when the blood leaks back or through the weakened doorway/valve/wall and moves back and forth between two chambers or containers. The flow is turbulent but it is shunted from one physical place to another through a "door" that should be sealed causing noise.......Example the water that keeps on running when the toilet is flushed and the plunger inside didn't seal properly.

They both make noise (are turbulent) but for different reasons.

DarkLotus · Jun 1, 2012

Okay so the sound is a murmur or bruit depending on the location of the turbulent blood. The turbulence is caused by the physical shunting of the blood within the heart. Shunts cause turbulent blood which can be heard as a murmur. I think I'm starting to understand what you all mean now by critical thinking! All this information was presented in differnt parts of the lecture but if I think about it I can link it all together.

Esme12, ASN, BSN, RN · Jun 2, 2012

Okay so the sound is a murmur or bruit depending on the location of the turbulent blood. The turbulence is caused by the physical shunting of the blood within the heart. Shunts cause turbulent blood which can be heard as a murmur. I think I'm starting to understand what you all mean now by critical thinking! All this information was presented in different parts of the lecture but if I think about it I can link it all together.

The murmur is what you hear by the shunting of the blood through a diseased valve or hole in the heart. The resulting sound is the turbulent blood flow over the diseased anatomy.

The bruit is what you hear in the blood vessel when the blood flow is swirling around and obstruction.....much like a river flows around the rocks....it makes a noise. The turbulence is inside the diseased vessel (carotids) or when you listen to the AV fistula that is created for dialysis.......a bruit in the neck is a sign of disease. A bruit in the AV (arterial venous) fistula....normal because of the vessels being made "larger" so they can acommodate an increased flow for dialysis.....where they meet makes the blood swirl, causing noise.

nurseprnRN, BSN, RN · Jun 4, 2012

you might hear the terms "left-to-right shunt" or "right-to-left shunt." what this means is blood moved from the left side of the heart to the right side of the heart through a ventricular septal defect or atrial septal defect (l to r), or from the right side of the heart to the left side of the heart (r to l).

left-to-right shunt is the most common, and often never diagnosed, because the left heart generates higher pressures than the right heart; the left ventricle is thicker and stronger than the right ventricle, because the lv has to pump blood out to the whole body and the rv only to the lungs. so if there's a hole in the septum between them, some of the blood in the lv will scoot over to the rv. since that blood is already oxygenated, if the great vessels are laid out properly anyway, there's not always any harm done. if there's a huge l-to-r shunt, the higher pressures can do damage to the pulmonary vasculature; again, not that common.

right-to-left shunts are most often seen when there is a hypoplastic (smaller than normal) lv plus a septal defect, and in some other kinds of congenital cardiac malformations. right-to-left shunts are really bad news because the blood that then goes out the aorta isn't well-oxygenated....bad idea. those of us who are old enough to remember back before pediatric heart surgery was what it is now remember "blue babies," those translucently fragile kids whose blood flow r-to-l made them, well, bluish-purple-- lousy peripheral oxygenation. many didn't live more than a few years as their bodies outgrew their hearts' ability to deliver oxygen.