Children with CHD will face a range of diagnostic tests during their medical care and treatment. The diagnostic tests described in this appendix will help your family understand these tests, what happens during them, how to prepare your child for them, and when you can expect the test results.

Every child with CHD is different, so the types of tests needed are different from child to child.

Not every test in this appendix will apply to your child.

clipboard iconThis appendix covers the following diagnostic tests:

Bloodwork

Also known as blood tests, bloodwork checks the components in your child’s blood, such as

  • medication levels (whether your child is getting enough or too much of prescribed medications),
  • electrolytes (whether the elements in your child’s blood, such as sodium and potassium, are in balance),
  • hemoglobin (whether the blood is carrying enough oxygen to supply cells throughout the body),
  • white blood cells (whether your child has an infection or the ability to fight an infection),
  • kidney function (how well the kidneys are working).

What will happen during the test?

A needle will be inserted into your child’s vein to take a small amount of blood.

We recommend leaving bloodwork until the end of a clinic visit, because children may get upset with the needle poke.

What can we do to prepare our child?

Parents can help by remaining calm and comforting. It is best for you to be with your child. Providing a treat and lots of praise afterwards can also help for the next time testing is needed. If your child is very upset by bloodwork, speak to the clinic nurse about using a local anesthetic cream or some play therapy that may help your child cope.

When will the results be available?

Depending on the type of blood test, some results are available within hours, while others take several days or even weeks.

Chest X-ray

A chest X-ray is a picture of the inside of the chest: the heart, lungs, and bones.

X-rays are a form of radiation. X-rays create an image of the organs and bones inside the body. Dense structures, such as bone, appear white, while air is black. Soft tissues, such as the heart, appear in shades of grey.

A chest X-ray provides information about

  • the size and shape of the heart,
  • abnormal fluid in or around the heart or lungs,
  • pneumonia or a collapsed lung.

What will happen during the test?

The chest area needs to be free from clothing and any form of jewellery or metal, so hospital gowns are provided. Babies lie flat on a special table for the X-ray. Toddlers may sit in a special chair, and older children may stand.

Since it is important to stay still for the X-ray, some younger children may need to be restrained. It can be upsetting to see your child restrained like this and, although the test does not hurt, some children cry because they are unable to move.

Older children may be asked to help by taking a deep breath and holding it for five seconds while the X-ray is being taken. This helps to fully inflate the lungs with air to get a better picture.

What can we do to prepare our child?

The large equipment and darkened room used for X-rays can be frightening to some children. You can prepare your child by explaining that the machine is just like a big camera.

Many parents, older children, and teens have concerns about the harmful effects of radiation. You can explain that technicians are trained to use the least amount of radiation possible and take the fewest number of X-rays to minimize exposure to radiation. A protective lead apron will be placed over your child’s pelvic area to minimize exposure of reproductive organs to radiation.

When will the results be available?

The radiologist usually looks at the X-ray soon after the test, depending on how urgent it is. If it is a routine test, the radiologist will contact your doctor with the results, who will discuss them with you at your next visit. If the X-ray is done for an urgent problem, they will discuss the results with you on the day of the test.

CT scan

A CT scan is a form of X-ray. It is painless but the child must not move during the scan.

In a CT scan, a computer is used to make a picture of a part of the body we want to see. CT scans are different from plain X-rays because they show different types of tissue inside an organ, like bone and fat, as well as fluid in the tissues.

What will happen during the test?

Your child will lie on a narrow table, held safely by straps or bands. The table then slides into the scanner, which looks like a large doughnut. The camera moves around in the scanner, taking many pictures. The computer then combines the pictures to form an image. Your child will see a moving light and hear a whirring noise, but the CT scan does not hurt.

It is important that your child lie very still during the test, which may take about 20 minutes. Babies and young children may need to be sedated for the test, in which case, your child will need to fast (not eat) for several hours beforehand.

A CT angiogram is used to show how the blood flows through the heart and the vessels in the chest area. An intravenous line will be used to give the dye that highlights the blood flow.

What can we do to prepare our child?

Your infant or child can expect to wear a hospital gown during the test. They will have to lie very still during the procedure. If your child needs sedation or an angiogram, they will have an intravenous line inserted. Children older than five who do not need sedating can practise lying very still.

Are there any side effects or after-effects?

Not usually. Occasionally the dye gives a feeling of warmth or nausea that goes away quickly. Tell the radiologist about any allergies or other reactions to dyes in the past. If your child is sedated for the test, the staff will tell you about any after-effects to expect.

When will the results be available?

The radiologist will write a report to the cardiologist, and the results may take several days.

Echocardiogram

Also known as a cardiac ultrasound, an echo, or a transthoracic echo, an echocardiogram is a painless test that allows the doctor to see a very detailed picture of the heart.

An echo uses ultrasound (harmless sound waves that cannot be heard) to create a video of the heart as it is beating. The sound waves are sent and received by a transducer, a device shaped like a small microphone that vibrates slightly. The sound waves are sent into the chest, where they bounce (or echo) off the muscles and valves of the heart. The transducer picks up the echoes and sends them to the echo machine, where they produce a live image of the heart on a screen.

A 3-D echo enables the heart to be seen from many different angles.

A 3-lead ECG (see Electrocardiogram) is done at the same time as the echo to help interpret the results.

The test provides the doctor with information about

  • the shape and condition of the muscles and valves of the heart,
  • how well the heart muscles and valves are working,
  • whether the blood is moving properly through the heart,
  • whether there are any blood clots.

What will happen during the test?

Three patches will be placed on your child’s chest and attached by wires to the ECG machine. Gel that has been warmed to body temperature will be applied to your child’s chest. The technician will hold the transducer on your child’s chest and move it around to get pictures of different parts of the heart from different angles. At the same time, the technician will watch the television screen closely to make sure all of the necessary information is collected.
To make sure that the technician is not distracted during the test, your child will need to lie fairly still. The test will take from 20 to 45 minutes.

What can we do to prepare our child?

Explain to your child that the test will not hurt, but that they will need to lie quietly while the test is being done. Reassure your child that you will stay throughout the test. If your child seems anxious about the test, consider a play activity at home to recreate the test, using a doll or action figure and a washable, sticky substance, such as fingerpaint or pudding.

Your child will need all clothing removed from the upper body. Gowns are provided to older children to protect their modesty. The gel is washable but sticky, so avoid dressing your child in any clothing you do not want soiled.

Some children find listening to music or watching a movie during the procedure makes it easier to lie still. You can help your child select the entertainment before the test. If your child is a baby, you may settle them with a soother or feeding. Toddlers sometimes need medication to help them lie still during the test. If your child needs medication, the doctor and the clinic nurse will discuss it with you. You may stay with your child throughout the test.

When will the results be available?

The results will be available once the doctor has reviewed the video and will be discussed with you before you leave the clinic.

Electrocardiogram (ECG or EKG)

An electrocardiogram (ECG or EKG) is a quick, painless test that measures the electrical activity of the heart.

The heart produces a tiny amount of electricity every time it beats. Electrodes (sticky patches with snaps) applied to your child’s body detect this electrical activity. The information is sent from the electrodes to the ECG machine through wires called leads (pronounced “leeds”). The information is recorded continuously and is printed out on a strip of paper.

No electricity goes from the machine to your child.

The ECG recording provides information about

  • heart rate (the speed of the heartbeat),
  • rhythm (the form of the heartbeat),
  • pattern (the shape of the heart’s electrical activity),
  • mass (the size of the heart).

The type of ECG depends on the number of leads used to collect the information. A larger number of leads mean more information can be collected. The most common type of ECG for a child with a heart condition is a 12-lead ECG. In addition, ECGs are used for Holter monitoring and stress testing.

Diagram of an electrocardiogram

Diagram of an electrocardiogram

What will happen during the test?

An ECG technician will apply electrodes to specific places on your child’s upper body and legs. If your child is a small baby or toddler, you will be asked to remove all of your child’s clothing except for the diaper or underwear. If your child is older, you can help or ask your child to remove clothing. Gowns are usually provided to older children to protect their modesty.

Your child will need to lie still for a few breaths while the ECG is being done. If the child moves around too much, the ECG may need to be repeated. When the ECG is finished, the electrodes can be removed.

What can we do to prepare our child?

Reassure your child that the test will not hurt. Younger children may be worried that removing the stickers will be painful. A play activity involving removable stickers may reduce the child’s anxiety. Let your child apply stickers and then remove them from a doll or action figure to show your child how easy it is.

When will the results be available?

Your doctor will discuss the results of the test with you before the end of your clinic visit.

Heart catheterization

A heart catheterization is a test in which a catheter (a flexible tube containing special sensors) is inserted into the heart through one of the large blood vessels. An angiogram is often required, which involves a dye being injected into the catheter to outline the flow of blood in the heart, lungs, and chest area.

The test gives the cardiologist detailed information about

  • the pressure in the chambers of the heart and its large blood vessels,
  • the amount of oxygen the blood carries to and from the heart,
  • the amount of blood pumped into the body with each beat.

The test is done under sedation or a general anaesthetic and takes two to three hours to complete.

What will happen during the test?

Most children having a heart catheterization are admitted to the hospital for the day through the surgical anaesthetic unit. Your child will go into the hospital on the morning of the test. They are usually allowed to leave that evening but may need to stay overnight in the hospital so their condition can be monitored.

Your child will not be allowed to have anything to eat or drink for several hours before the test. The number of hours depends on your child’s age. Keeping your child’s stomach completely empty helps prevent vomiting during or after the procedure. It is important not to give your child a drink or snack, since even a small amount of vomited food or drink can enter the lungs and cause pneumonia.

If your child is on any medications, check with your doctor or hospital staff about whether to give the medication on the morning of the test. If the medication is to be given, it should be taken at least three hours before the test. If your child has any allergies to medications, be sure to tell the hospital staff.

If your child is taking any medication to prevent blood clots, such as Aspirin (also known as ASA) or warfarin, your child must stop taking the medication before the procedure. The cardiology clinic nurse will tell you when to stop these medications. If this is not part of the instructions you were given, call the clinic nurse for specific information.

The heart catheterization will be done in a special procedure room. The anaesthetist will talk to you about the type of sedation or anaesthetic being used on your child. If a sedative is used, your child will be awake but drowsy and breathing on their own. If an anaesthetic is used, your child will be asleep during the procedure and a breathing tube will be used to help them breathe. A parent may stay with the child while an IV line is put into a vein in your child’s hand or foot. An anaesthetist will give your child a sedative or anaesthetic through the IV. You will be escorted back to the waiting area as soon as your child is asleep.

When your child is ready, the site where the catheter will be inserted will be cleaned and a local anaesthetic will be injected to numb the area. The groin (the crease at the top of the leg) is the usual site as the big blood vessels in the leg come close to the skin surface, although other sites are sometimes used.

Once the catheter is in place, the cardiologist will do specific tests and measurements to learn how the heart and blood vessels are working. After the tests, the catheter will be removed. The small wound will be covered with a Band-Aid.

Your child’s heart will work normally during the test. Blood pressure, ECG, and oxygen saturation will be monitored continuously during and after the test.

With the help of an anaesthetic or sedative, most children sleep comfortably through the procedure and do not feel anything. Some children may feel a sting when the freezing is injected. Your child may feel pressure as the catheter goes in but will not feel the catheter moving in the blood vessel. If an angiogram is done, they may feel a warm flush for a few seconds.

Your child will go to the recovery room for about an hour before returning to the daycare or ambulatory unit. Once awake, babies can have clear fluids such as sugar water, and older children can have a Popsicle or apple juice. As long as clear fluids do not cause an upset stomach, your child can then eat a light meal.

After at least four to six hours in the recovery room, most children can go home. Your child will probably feel sleepy after the test and will need to lie quietly in bed for the rest of the day.

Most children can follow normal routines the next day.

Wait 24 hours before giving your child a tub bath. You can give your child a sponge bath (wash them using a damp sponge or cloth) as soon as you wish.

You may remove the Band-Aid 24 hours after the test. The groin may have a bruise and feel sore for a day or two.

If you are from out of town, plan to stay in the area the night after the heart catheterization.

What can we do to prepare our child?

Tell the staff about any allergies or reactions that your child has to food or other substances.

Babies and toddlers may be more relaxed if they have a special stuffed animal, blanket, toy, or pacifier with them for the test. If your child is older and is going to be sedated (sleepy) rather than having a general anaesthetic, they may want to listen to some favourite music during and after the test.

When to tell your child about the test depends on their age. You can tell your toddler the night before or the morning of the test. Older children can be told further in advance so that they can ask questions, which you should answer honestly.

Let your child know that you cannot be in the room during the test, but that they will be sleepy or asleep during this time. Reassure your child that you will be there when the test is finished.

Are there any risks or complications?

Skilled professionals do the heart catheterizations and they handle the child and equipment with great care. Damage to the heart during a catheterization is rare. However, there are risks with this test.

As the parent or guardian, you must sign an informed consent. This legal document states the cardiologist has explained the reasons for doing the test and you understand the risks and benefits.

Ask questions and discuss your concerns with your cardiologist before signing the informed consent.

The possible risks of a heart catheterization include

  • an allergic reaction to the contrast solution or sedation during the test,
  • irregularities in heart rhythm during the test,
  • formation of blood clots during or after the test (If the leg where the catheter was inserted swells, looks paler, or feels cooler than the other, this may mean that a clot has formed.),
  • swelling or redness at the insertion site
  • fever, which may indicate that there is an infection,
  • a small amount of bleeding from the catheter insertion site in the groin. If this happens
    1. Place a piece of gauze or cotton over the site.
    2. Press down firmly for 10 minutes.
    3. Press firmly for another 10 minutes if the bleeding continues.
    4. Keep pressing until the bleeding stops.
    5. Cover with a Band-Aid when the bleeding stops.
    6. Remove the Band-Aid 24 hours after the bleeding has stopped.

Call your cardiologist or clinic nurse if you have any concerns.

When will the results be available?

Your cardiologist will talk to you briefly in the daycare or ambulatory unit when the procedure is over to tell you how your child is doing. After the cardiologists and surgeons have studied the test results, your doctor will contact you to discuss findings and possible treatments.

Special procedures during a heart catheterization

Other procedures are sometimes done during a heart catheterization. Your cardiologist will discuss any special procedures with you first.

Magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) of the heart uses magnetic and radio waves to produce signals that a computer forms into very detailed images of the anatomy and function of the heart and blood vessels.

An MRI is so detailed that it can show the different tissues that make up the heart, including the heart muscle (myocardium), the tissue covering the heart (the pericardium), and the blood inside the heart.

There are no known side effects to an MRI.

What will happen during the test?

The MRI machine is large and shaped like a tunnel. Your child will lie on a narrow table that slides in and out of the tunnel. For safety, your child will likely be strapped to the table. The image can be blurred if the child moves around too much, so very young children may be sedated or given a general anaesthetic.

Children who need sedation or a general anaesthetic are not allowed any food or drink for several hours before the test. If the stomach is completely empty, this helps prevent your child from vomiting during or after the procedure. It is important not to give your child a drink or snack, since even a small amount of vomited food or drink can enter the lungs and cause pneumonia.

If your child is on any medications, check with your doctor or hospital staff about whether to give the medication on the morning of the test. If the medication is to be given, it should be taken at least three hours before the test. If your child has any allergies to medications, be sure to inform the hospital staff.

Sleeping medicine will usually be given through an intravenous (IV) line. A local anaesthetic called EMLA will be placed on the back of your child’s hand to numb the skin. The IV will be inserted through the numbed skin. Your child will recover from the anaesthetic in a few hours and will have to stay in the hospital or clinic until they are fully awake. Your child may have a sore throat for a day or two.

An IV may also be necessary for injecting a contrast medium. A contrast medium is a material that moves through the blood to a part of the body, highlighting it on the image that is created.

Your child will not feel the magnetic waves. The machine is very noisy, making frequent knocking and humming noises. Children who are not sedated are given earplugs and may be able to listen to music.

A single test takes 45 to 90 minutes, depending on the type of machine.

Once awake, babies can have clear fluids such as sugar water, and older children can have a Popsicle or apple juice. As long as clear fluids do not cause an upset stomach, your child can then eat a light meal.

What can we do to prepare our child?

Your child may wear either regular clothing with no metal fasteners or decorations or a hospital gown. All metal jewellery must be removed. Let the technicians know if your child has implanted devices, such as a pacemaker or stents.

The machine looks frightening to some children. You can prepare your child by reassuring them that the test will not hurt, that the machine is a big camera that makes a lot of noise, and that you will be in the room the whole time.

Your child may bring a toy, blanket, or other soothing item for the test as long as it does not have any metal pieces.

When will the results be available?

The radiologist will write a report to the cardiologist, and the results may take several days.

Oxygen saturation test

Also known as oximetry or sats, the oxygen saturation test is a painless test that checks the amount of oxygen in your child’s blood.

During a sats, a probe shines a special type of red light through a small body part, such as a finger, toe, or earlobe. The probe senses any changes in the light and uses this information to calculate the amount of oxygen in the blood.

What will happen during the test?

A small sensor will be wrapped around either a toe or a finger and held in place by special non-sticky tape. The sensor will be attached to a small hand-held machine called a pulse oximeter. The test is very quick, but your child needs to be still for an accurate reading. This can take a few minutes with younger children and babies.

This test may also be done to check the oxygen saturation level while your child is exercising or to monitor oxygen saturation continuously while your child is in hospital.

The probe generates heat, so the probe site will be changed regularly when used for long periods.

What can we do to prepare our child?

The probe looks like a Band-Aid and is wrapped around a fingertip or a toe. It is not sticky, and it does not hurt to remove it.

When will the results be available?

The results are available immediately.

Transesophageal echocardiogram (TEE)

A transesophageal cardiogram (TEE) uses the same technology as an echocardiogram to provide very clear images of the heart from behind the heart (see Echocardiogram).

Instead of collecting the images by moving a transducer over the child’s chest like an echocardiogram, a TEE inserts a special tube-shaped transducer into the esophagus. The esophagus is the tube that lies right behind the heart and connects the mouth to the stomach. The cardiologist will use the transducer to record images of the heart.

A TEE helps determine whether the following are happening:

  • abnormalities in the heart muscle, valves, or major blood vessels to and from the heart
  • weak heart muscle and leaky valves
  • blood clots or infection in the heart

This test may also be used during surgery when it is not possible to do a transthoracic echo.

For this test, your child will be given a general anaesthetic. To avoid giving your child anaesthetics too often, a TEE may be done at the same time as another planned procedure that uses a general anaesthetic.

What will happen during the test?

Your child will not be allowed anything to eat or drink for several hours before the procedure. Keeping your child’s stomach completely empty helps prevent your child from vomiting during or after the procedure. It is important not to give your child a drink or snack, since even a small amount of vomited food or drink can enter your child’s lungs and cause pneumonia.

If your child is on any medications, check with your doctor or hospital staff about whether to give the medication on the morning of the test. If the medication is to be given, it should be given at least three hours before the test. If your child has any allergies to medications, be sure to tell the hospital staff.

An intravenous (IV) line will be inserted for the general anaesthetic. A local anaesthetic called EMLA will be placed on the back of your child’s hand to numb the skin, and the IV will be inserted through the numbed skin.

Once your child is under general anaesthetic, the cardiologist, with help from the echo technician, will pass a small tube-shaped transducer into your child’s esophagus and record images of the heart. Your child will recover from the anaesthetic in a few hours and will have to stay in the hospital or clinic until fully awake. Once awake, babies can have fluids such as sugar water, and older children can have a Popsicle or apple juice. As long as clear fluids do not cause an upset stomach, your child can then eat a light meal.

Your child may have a sore throat for a day or two.

What can we do to prepare our child?

Reassure your child that they will be asleep during the procedure and will not feel anything. Your child may bring a toy, blanket, or other soothing item for the test.

When will the results be available?

The results of the test will be discussed with you as soon as the doctor has reviewed the information. This is often done immediately.

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