About this video
Explains non-cyanotic congenital heart disease, where a defect such as a hole in the wall between the ventricles lets blood flow from the left side of the heart to the right. A doctor can detect it by listening with a stethoscope for auscultation, by imaging with a chest x-ray or echocardiogram, and by reading electrocardiogram changes that show an enlarged right ventricle or atrium.
You'll be able to
- explain how a congenital left-to-right shunt makes blood flow from the left heart to the right.
- describe how a doctor can hear, see and measure a non-cyanotic heart defect.
- predict how extra load on the right ventricle changes the heart muscle and the ECG.
Key words
- Non-cyanotic heart disease
- A congenital heart defect in which blood moves from the left side of the heart to the right without causing a blue colour in the body.
- Congenital
- Present from birth, as with a defect that forms before or during development.
- Auscultation
- Listening to the heart with a stethoscope to detect abnormal sounds caused by a defect.
- Echocardiogram
- An ultrasound image that shows the heart beating in real time, including valves and defects.
- Electrocardiogram (ECG)
- A recording of the heart's electrical signals, with P waves for the atria and QRS complexes for the ventricles.
Transcript
Voiceover: With non-cyanotic heart dieseae, you have some type of a congenital defect. Congenital just means that the individual is born with it, but what happens as a result is that blood moves from the left side of the heart to the right side of the heart. In this example, you see that we have a little hole here in the wall between the left ventricle and the right ventricle.
Since the pressure is higher on this left side that's sending the blood throughout the entire body, that is going to cause blood to go from the left to the right ventricle. Now, my question is, how does the doctor diagnose that an individual has some non-cyanotic heart defect?
Well, one of the first things is that you can hear it. So, let's draw a little ear here. You'll be able to hear it, and also, you should be able see it. We'll talk about how you can do those things ... let's put a little pupil here. All right, so, you'll be able to hear it, and you'll be able to see it.
Now for the hearing, well, just think about it this way. Let's say you have a garden hose. This is my garden hose, and we have water that's flowing through that garden hose, and all of a sudden, we decide "Hey we're going to put a little tiny hole in the hose."
So, right here we have a little hole. What's going to happen? Well, of course, you're going to have water flying out in places that you don't want it to go, and it's going to kind of squirt in this direction. If you come closely here, you'll be able to hear that.
Right? Yeah! Of course, that makes sense. Well, how does a doctor do that? Well, the doctor can't go in and put his ear right by that hole. What he can do is take this little handy device that we're all so familiar with, that's called a stethoscope, and this end, it's going in his ears.
Then, you have this tube, and then, you have this chest piece, and where you can listen to the sounds of the heart. Depending on the type of non-cyanotic heart disease that individual might have, he'll be able to hear the squirting or some type of a characteristic sound that's the result of that defect.
This process, I'll give you a fancy name for it, it called auscultation. All right, so, that is when the doctor comes with the stethoscope and since this is a congenital defect, when the baby is just born, he listens to the sound of the heart, and say, "Hey. I'm hearing something that's it's not exactly what I would like to hear."
So, that is one way, by listening to the heart. Then, you can see the heart. How do you see the heart? Well, by taking a picture. Unfortunately, you can't just take a regular camera. You need a more expensive machine, and that expensive machine is going to allow you to be able to visualize the chest area, and with that, it's just like we're taking a picture.
It's just a little different. It's not going to have all the nice fancy colors, and you'll be able to see the heart. All right, so, this is my heart. This is called a chest x-ray. All right. You going x-ray machine. You put the baby in the x-ray machine. You take a picture, and you look to see, all right, is there some type of a structural defect that's not suppose to be there?
That's one way to visualize the heart. There's a second way to visualize the heart that's even better. Yeah, you can take a picture, or you can take a video. Right? With a fetal or postnatal ... so, fetal is while the fetus is still inside the mother's womb, and postnatal, once that baby is born, you take an echocardiogram.
So, echo ... ooh, that doesn't look right. Echocardiogram. What that does is you're using sound waves, and you're projecting it onto a screen, so, that you can see the heart. You see the heart as it's beating. You see it contracting. You see the valves closing.
You can also see in real time if there are defects that should not be there. So, that's number two. We can visualize the heart by either using a chest x-ray or a fetal or postnatal echocardiogram. There are some other issues that we might notice with non-cyanotic heart disease.
We said that blood is going from the left side to the right side, and if you have more and more blood going to the right side where it's ultimately going to your lungs, so, you have more gong to your lungs some coming back but not going as much to the body, eventually, you're going to get buildup in pressure in your lungs.
If you get a buildup in pressure in your lungs, that can feed back to the right side causing buildup in pressure over here too. If we have that buildup in pressure over here, the ventricle has to do much more work. Now, if you go to the gym, and you're exercising, and you're doing a lot of work, what's going to happen to your muscles?
Well, their going to get larger. Their going to get significantly stronger. That's going to start to happen on the right side where you have a larger heart muscle. If you have larger heart muscle, you will notice this when a doctor comes and does an electrocardiogram.
So, we take an electrocardiogram. Cardiogram where we are looking at the electrical signals throughout the heart. With that, I'm going to just sketch one out. Right now we have our P wave, and then, our QRS complex, and then, we have our T wave. If I look at that, so, this P wave, our QRS complex, and then, we have our T wave.
The P wave gives me the electrical activity of the atria. The QRS complex is given you the electrical activity of the ventricles. All right. I'm not going to go into all the details. I'm just going to kind of make it just that simple for now. If you have enlargement of the ventricles, or the right ventricle, what's that going to do to the signal?
Do you expect to see the same signal, a larger signal, a smaller signal? Well, if you have a bigger muscle, I would expect to see a significantly larger signal here with the ventricles. If that feeds back to your atria, and you have a larger right atrium, well, you might see this being a larger, a little broader, a little wider.
There are characteristics features that you can see in the electrocardiogram, the ECG or EKG, depending on where you are in the world. That can give you an indication as to whether there is some type of a dysfunction in the heart, as a result of the load that's placed on the right ventricle, and the right atrium, and enlargement of those structures.
So, you can hear it. You can see it. There are some functional things that you can notice in the electrocardiogram to help diagnose a non-cyanotic heart defect.
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