Posts Tagged ‘Pulmonary Artery’

TGA Explained by a Doctor

August 25, 2009

Here’s a great article, one so good it makes me wish that I had written it. PalMD, who posts on the blog White Coat Underground, takes the time to describe Transposition of the Great Arteries (TGA). No matter if this is your defect or not, hustle over there and learn more. Because as PalMD says,

Heart-lung physiology is pretty cool stuff.


Basic Cardiology: How the Heart Works

December 14, 2008

95% – perhaps more – of Heart Moms and Dads have no medical training. You probably have a normal, non medical job, and never really thought about the heart until that fateful day when a doctor sat you down and said “We think there could be a problem with your child’s heart…”

If you want to try to stay one step ahead of a Congenital Heart Defect, you’d better learn all you can about a complex organ in a very short time. It can difficult, especially when you are under pressure – how many times have Heart Parents asked their doctor to hold on just a moment and explain what he’s saying? You’d be surprised at how much heart parents without medical backgrounds know about the human heart, but when you are trying to learn so much as rapidly as possible, you get swamped. It can feel as if you are trying to trying to drink from a fire hose.

So let’s slow down, and take a walk through a healthy human heart. First, here’s a nice diagram we can follow. If you have an engineering background, or a chart just makes more sense, you might want to look at this schematic. (You can click this chart and make it bigger!)

The heart is not a pump. It’s actually two pumps fused together – The right side pumps blood to the lungs and back; the left side of the heart pumps blood through the body. Blood that has already made the trip through the body flows through the Superior Vena Cava and the Inferior Vena Cava into the Right Atrium. This blood has little oxygen. The Atrium contracts, squeezing the blood through the Tricuspid Valve into the Right Ventricle. When the Right Ventricle contracts, the blood is squeezed through the Pulmonary Valve into the Pulmonary Artery, and then to the lungs.

There are two large blood vessels on top of the heart. The Aorta rises out of the Left Ventricle, loops downward and carries blood to the lower half of the body, which makes it look like an upside down U. The Pulmonary Artery splits just after it leaves the heart, taking blood to the right and left lung. This makes it look like a T, and it is tucked neatly into the arch created by the Aorta.

The Pulmonary Artery is also misnamed. Every artery in the body carries blood with a high oxygen content… except the Pulmonary Artery. Yes, it sounds strange, but it matches an older definition of arteries and veins: Arteries move blood away from the heart, veins move blood towards the heart.

In the lungs carbon dioxide is exchanged for oxygen and the blood returns to the heart, arriving in the Left Atrium. The left Atrium contracts, and blood flows through the Mitral Valve into the Left Ventricle. When the Left Ventricle contracts, blood flows through the Aortic Valve into the Aorta, and out into the body.

You’ll notice that while the Right Ventricle is larger, its heart wall is not as thick. The Right Ventricle is not a very strong pump, but that’s ok… all it has to do is move the blood to the lungs and back. The Left Ventricle is just a little smaller but the heart wall is thicker. It’s the heart’s main muscle, delivering a powerful squeeze to send blood throughout the entire body. This is one of the main reasons why right-side heart defects (like Tricuspid Atresia) have been survivable for some time while left-side defects are much more difficult. As I’ve mentioned before, Hypoplastic Left Heart Syndrome (HLHS) was almost 100% fatal until the mid 1980’s, and the oldest HLHS survivors are just reaching adulthood.

I hope this basic look at a heart has been helpful to you. Some of Funky Heart‘s readers learned all this long ago, and they may find it a little boring. But in the United States, someone  is born with a Congenital Heart Defect every fouteen minutes. There is always a need to review the basics!

My Glenn Shunt is worth more on eBay!

October 13, 2008

Yeah, you read that right. My Glenn Shunt would bring a higher price on eBay! Yours? Not so much. I have a classic vintage model, so the price would be higher!

I’m kidding with you, obviously. If you happen to need a Glenn Shunt (or any other heart operation) then the true cost is out of your reach; it’s priceless.

The Glenn Shunt is one of the oldest heart operations around. It was first described in 1951, and Dr. William Glenn of Yale University first reported performing the procedure successfully in 1958. Since he was the first person to routinely have success, the operation bears his name. (If you or someone you know has a Glenn shunt, please click THIS LINK and download and read the PDF file. There is a lot of important information here that you need to know!)

When I tell people I have a Glenn Shunt, the ones who know what I’m talking about will nod their heads knowingly. Most of the time, though, they are still wrong. My Glenn was done in 1967, and I am a proud owner of a Classic Glenn Shunt. Most of the Glenns done today are the Bidirectional Glenn Shunt.

So what’s the difference? Before you describe the Glenn, it helps to have a diagram to help you visualize it. Click HERE for a useful diagram of the heart.

In the Classic Glenn, the Superior Vena Cava (The large vessel that leads into the Right Atrium) is closed near the Right Atrium (usually, it is not cut, but rather sewn closed.) The Pulmonary Artery (the “T” shaped blood vessel that runs under the “loop” formed by the Aorta) is also cut… the right branch of the Pulmonary Artery is disconnected. The hole left by cutting the right branch of the Artery is sewn closed, and then the right branch is connected to the side of the Superior Vena Cava.  By doing this, the Right Atrium is completely removed from the blood flow. Blood coming to the heart through the Superior Vena Cava now goes directly to the Right Lung, and flows back to the Left Atrium normally. Then it goes through the Left Ventricle and back out to the body.

The Bidirectional Glenn was invented, surprisingly, in 1966. While it was around when I had my Classic Glenn in 1967, my operation was the fifth Glenn Shunt (of any kind) that had been performed at Johns Hopkins; so it is a safe assumption that the surgeons weren’t prepared to try the new version just yet. In fact, the Bidirectional Glenn really came into its own in the 1980’s, when it became the second step in the three operation Norwood Procedure used to combat Hypoplastic Left Heart Syndrome (HLHS).  It’s also part of the Fontan Procedure, sometimes performed as a seperate operation as part of a Staged Fontan.  The biggest difference in the two operations is that in the Classic Glenn, the Superior Vena Cava is completely cut and sewn into the right branch of the Pulmonary Artery. In the Bidirectional Glenn the Pulmonary Artery is not cut, which allows blood flow to both lungs.

It’s important for someone with a Congenital Heart Defect (CHD) to know what “version” of an operation they have had. For years, I told doctors “I have a Glenn Shunt,” not knowing that the operation had been changed. After I had told a new doctor that I had a Glenn Shunt, he slapped my X-Ray on the lightboard, took a long pause, and finally said “I don’t know what the hell this is, but it ain’t no Glenn Shunt.” Only after the head of the Cardiology Department came in and said “I haven’t seen one of those in a while!” did I realize that simply saying “Glenn Shunt” wasn’t good enough. Thankfully that snafu occured during a routine office visit and not a crisis visit to an Emergency Department.