Chapter 3: Learning | Children’s Heart Network

Heart and Soul cover

This chapter helps your family learn about the cardiovascular system—the heart, valves, and blood vessels—and what the system typically looks like before and after birth. It provides general information about congenital heart disease (CHD) and related health concerns. The chapter also helps you learn about medication delivery and safety, and how to find trustworthy online resources to increase your knowledge.

Understanding the cardiovascular system

Every cell in the body needs oxygen and nutrients to work properly. The cardiovascular system (from cardio, meaning “heart,” and vascular, meaning “blood vessels”) refers to the heart and blood vessels that pump blood, carrying oxygen and nutrients throughout the body.

The heart

Your child’s heart is a hollow, muscular organ about the size of your child’s fist. It is located between the lungs, shown below, usually slightly to the left of the middle of the chest.

Diagram of the heart and lungs

WRITE AND ASK
A tip from the health care team: write down your questions as you think of them. Don’t be afraid to ask them.

Take a look at the “Diagram of the heart” on the next page. Here are the main parts of the heart shown:

the septum—a wall dividing the right and left sides of the heart
the atria—the two upper chambers of the heart, one on the right side and one on the left side
the ventricles—the two lower chambers of the heart, one on the right side and one on the left side
the valves—the small structures (like doors) inside the heart that open and close when the heart beats. There are four valves: the mitral valve, the aortic valve, the tricuspid valve, and the pulmonary valve.
the aorta—the artery that carries blood rich in oxygen to the body
the superior vena cava—the vein that carries blood low in oxygen from the upper body to the heart
the inferior vena cava—the vein that carries blood low in oxygen from the lower body to the heart
the pulmonary artery—the artery that carries blood low in oxygen to the lungs
the pulmonary veins—veins in the heart that return oxygen-rich blood from the lungs back to the left atrium (collecting chamber). There are four main pulmonary veins, two from each side of the lungs.

Diagram of the heart

The heart at work

The heart is a two-sided pump. Clench your fist, relax it, and clench it again. This squeezing and relaxing is similar to how the heart beats or pumps.

The heart collects oxygen-poor blood, pumps it to the lungs to get oxygen, and then pumps it (oxygen-rich blood) out to the body through arteries.

Here is how it works:

The right atrium, a collecting chamber, receives oxygen-poor blood.
The right atrium squeezes, which pushes open the tricuspid valve (the “door” to the right ventricle); the blood moves through the valve into the right ventricle.
The right ventricle, a pumping chamber, squeezes, which pushes open the pulmonary valve (the “door” to the pulmonary artery).
The pulmonary artery carries blood low in oxygen to the lungs, where carbon dioxide is removed and oxygen is added.
Blood rich in oxygen returns to the heart through the pulmonary veins to the left atrium.
The left atrium squeezes, which forces the blood through the mitral valve into the left ventricle.
The left ventricle squeezes, which pushes the aortic valve open.
With each beat of the heart, blood flows through the aortic valve into the aorta, which branches into smaller arteries that supply the body with oxygen-rich blood.
Blood flowing through the arteries creates the pulse (heartbeat) you can feel with your fingertips.

The heart’s electrical system

Take a look at the “Diagram of the heart’s electrical system” on the next page. The heart’s own electrical system makes the heart beat through a series of actions:

The sinoatrial node (SA node)—the heart’s natural pacemaker, located in the right atrium—sends out electrical signals (or impulses) that make the atria squeeze and pump blood into the ventricles.
The electrical signals travel to the atrioventricular node (AV node).
The AV node slows the signals slightly, which allows the blood to pass from the atria to the ventricles.
The AV node then sends the signals to the bundle of His, a collection of heart muscle fibres that carry electrical signals into the ventricles.
The signals then make the ventricles squeeze and pump out blood to the body.
The Purkinje fibres make the squeezing and pumping of the ventricles happen at exactly the same time. This creates a regular heart rhythm.

When the electrical nodes are working well together, the heart pumps blood into the lungs and to the rest of the body. If the electrical system is not working well, the heartbeat (rhythm) may be irregular.

Diagram of the heart’s electrical system

DYSRHYTHMIAS
Electrical problems affecting the heart rate or rhythm are called dysrhythmias. They include bradycardia (slower-than-normal heart rate), tachycardia (faster-than-normal heart rate), and fibrillation (a disorganized or irregular heartbeat).

Healthy blood

Blood has many different parts.

The main parts are

red blood cells, which carry oxygen to the body,
white blood cells, which help fight infection,
platelets, which help the blood to clot,
plasma, which contains protein such as albumin.

Oxygen is needed by every part of the body. The red blood cells carry oxygen around the body.

The oxygen attaches itself to hemoglobin, a part of a red blood cell. When the hemoglobin is full of oxygen, the blood looks bright red. When the oxygen level is low, the blood looks purple or blue.

The cells use the oxygen and make the waste product called carbon dioxide.

When blood rich in oxygen leaves the lungs to be pumped around the body, it normally looks red. Blood returning to the heart is low in oxygen and high in carbon dioxide and normally looks blue.

Blood vessels

Blood is delivered throughout the body by a network of blood vessels, including arteries, veins, and capillaries:

The arteries carry blood away from the heart.
The veins carry blood back to the heart.
The capillaries (tiny blood vessels connecting arteries and veins) allow oxygen and nutrients to be delivered to the cells and waste products to be picked up.

Blood pressure

The heart muscle squeezes and relaxes in a rhythm, creating force against the walls of the arteries. Blood pressure is a measure of this force.

Here’s an explanation:

The squeezing, when blood is pushed out of the heart, is called systole (pronounced “SISS-tow-lee”).
The relaxing, when the heart refills with blood, is called diastole (pronounced “die-ASS-tow-lee”).
When the heart squeezes, a wave of blood is pushed out of the heart, putting pressure on the walls of the artery.
When the heart relaxes, pressure in the arteries lessens.

When blood pressure is measured, two numbers are recorded. The first number is called the systolic pressure (when the heart squeezes), and the second number is called the diastolic pressure (when the heart relaxes). For example, a blood pressure of 120/80—said as “120 over 80”—means 120 systolic and 80 diastolic.

Blood pressure can be too high (hypertension) or too low (hypotension).

The heart before and after birth

Before a baby is born, their mother provides what the baby needs. The placenta in the mother’s womb does the work of the lungs by adding oxygen and removing carbon dioxide. Oxygen in the mother’s blood moves across the placenta into the baby’s blood. This oxygen-rich blood is then carried via the ductus venosus and inferior vena cava into the baby’s right atrium.

As the baby doesn’t use its lungs to breathe until after birth, most of the blood bypasses the lungs through two connectors:

An opening in the septum between the two atria of the heart called the foramen ovale allows most of the blood to pass from the right atrium to the left atrium.
A blood vessel called the ductus arteriosus carries the blood from the pulmonary artery into the aorta.

Before birth, most babies with CHD do not have any problems because the placenta provides oxygen-rich blood to the baby and because oxygen needs in the womb are lower than after birth. Once the baby is born and the umbilical cord is cut, the mother’s and baby’s bodies become separate. Newborns then have to rely on their own lungs and heart for the blood and oxygen they need.

When the baby takes their first breath, the increase of oxygen in the blood and changes in pressure in the heart and lungs encourages the foramen ovale and the ductus arteriosus to close during the first few days of life. In some babies, these openings do not close when they should.

Diagram of the heart’s blood flow before birth

Diagram of the heart’s blood flow after birth

Understanding congenital heart disease

Congenital disease comes from the words congenital, meaning “existing at birth,” and disease, meaning “a problem.” The heart is completely formed by the eighth week of pregnancy. If a problem occurs in the forming of either the heart or the blood vessels near the heart, the baby is born with what is called congenital heart disease, or CHD for short. Congenital heart disease is sometimes called a congenital heart defect, also known as CHD for short. (See “Note” on page viii about using these terms.)

About 1 of every 100 babies born has some form of heart defect (i.e., 1% of babies). This ranges from a tiny hole in the heart that will never require treatment to a life-threatening heart defect.

Sometimes a CHD is associated with other health problems. For example, babies with Down syndrome often have a particular heart defect.

The cause of CHD

No one knows what causes most heart defects.

You may hear the term multifactorial causation. This means that it takes many things to cause the defect. When certain genetic and environmental factors occur at the same time, a heart defect may result.

Two things that increase the risk of getting a congenital heart defect are the family history of congenital heart disease and the mother’s health.

Family history

If you are the parent of a child with CHD, the chance of having another baby with some form of CHD increases from about 1% (1 in every 100 births) to about 3% (3 in every 100 births). It is rare for more than one child in a family to have a congenital defect.

Mother’s health

When a woman is pregnant, what happens to her body may affect the development of her baby’s heart. For example, illnesses such as diabetes (a disease in which the body doesn’t properly produce or use insulin) and rubella (a viral infection also known as German measles) can increase the risk of a baby having a congenital heart defect.

Did I do something wrong?

Many parents worry it is something they did or did not do that caused the heart defect. In most cases, there is nothing the parents could have done to prevent the defect.

If you have questions about the cause of your child’s heart defect, talk it over with your cardiologist or health care professional.

COMMON FACTS ABOUT CHD
CHD happens to about 1 in every 100 babies.
Congenital heart defects are more common than any other type of congenital defect.
Congenital heart defects are more common in children with other conditions, such as Down syndrome.

Understanding congestive heart failure

Congestive heart failure (CHF) does not mean that the heart will stop or a heart attack will happen. CHF is a condition when the heart is unable to pump an adequate amount of blood to meet the needs of the body.

CHF can take several days or weeks to develop. It may be mild when it first develops and slowly become worse.

CHF can be controlled. It is usually managed with medications. If needed, surgery may correct or reduce the problem that causes CHF.

CHF symptoms and causes

CHF is a group of signs and symptoms that include poor feeding, rapid breathing, sweatiness, rapid heart rate, and failure to gain weight.

CHF may be due to

abnormal communications or holes within the heart,
other abnormal structures of the heart or blood vessels that increase the workload on the heart, such as
- obstructed or leaky valves,
- narrowed blood vessels, or
- an abnormal heart rate or rhythm.

Other causes of CHF are less common in children and relate to poor heart muscle function.

Causes of poor heart muscle function include

cardiomyopathy, a disease of the heart muscle, often caused by an infection;
endocarditis, an inflammation of the inside of the heart (see infective endocarditis under “Common heart words” in the glossary); and
myocarditis, an inflammation of the heart muscle.

Signs your child has CHF

The health care team will be watching your child for CHF. However, as a parent, you spend more time with your child than the team does, so it helps to be aware of the signs or symptoms, which are described in the table on the next pages.

The signs of CHF are more noticeable in babies when they are feeding and in children when they are exercising and playing actively.

In babies with congenital heart disease, slow or inadequate weight gain or weight loss is often seen with CHF.

Issues with weight gain are due to the increased workload of the heart and lungs, a need for more calories than the child can take in, and lack of appetite due to fatigue.

Many signs, such as crankiness and irritability, are also seen in healthy children. However, when seen in combination with other signs and symptoms of CHF, it may mean that your child requires further assessment and treatment.

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What to do if you think your child has CHF

CHF develops slowly, over days and even weeks. It is not an emergency, but contact your pediatrician or family doctor if

there is more than one sign,
the signs don’t go away with rest,
the signs reappear every time your baby feeds or your child is active.

Even if your child shows more than one sign, it may not be CHF.

If necessary, your cardiologist will need to see your child again to assess and possibly treat the problem.

Understanding cyanosis

Cyan means “blue.” Cyanosis is blueness of the skin, lips, gums, nail beds, and the areas around the eyes and mouth. Some children with congenital heart disease have cyanosis. They are sometimes called blue babies.

Causes of cyanosis

Oxygen is carried in the blood by hemoglobin, which is bright red when filled with oxygen but becomes purple or blue when the oxygen level is low. Cyanosis occurs when the body has a lot of blue blood going through it.

Cyanosis can happen in children with CHDs for several reasons, like not enough blood getting to the lungs, or blue blood—coming back from the body—mixing in the heart with bright red blood.

Surgery can correct or reduce the cyanosis, and a child will rarely remain cyanotic for life.

Signs your child has cyanosis

Healthy children, particularly newborns, may have cyanotic hands and feet when they are cold because their bodies do not deliver enough blood to the tiniest blood vessels, the capillaries. This is called peripheral cyanosis and is normal.

“Central cyanosis” means that blood throughout the body is not carrying enough oxygen. Children with CHD who have this type of cyanosis may have a purple tinge to the lips, tongue, and nail beds.

To measure cyanosis, an oxygen saturation monitor is used (see oxygen saturation test in Appendix A). This test is now routinely done on every baby before they leave the hospital to screen for congenital heart disease.

Effects of cyanosis on your child

Cyanosis by itself is not a problem, since before birth every baby develops with low oxygen saturations around 60%. However, both the degree of cyanosis and the longer it continues after birth, the more it will affect your child’s health. This table lists the most common effects of cyanosis on your child:

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Things to watch for if your child has cyanosis

Children with cyanosis may need to have the hemoglobin level in their blood measured to make sure it is not too high or too low.

A low hemoglobin level (anemia) may mean your child is anemic and may need an iron supplement. A high hemoglobin level can cause the blood to be thicker than normal (polycythemia).

This table describes other things to watch for if your child has cyanosis:

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Understanding medications

Your child may need medications to manage their CHD. Some children may need medications for a short time, such as before or after surgery, while others may need medications for life.

Tell the doctor, pharmacist, or nurse if your child

has ever had an allergic reaction or bad side effect from any medicine,
has any diseases or conditions other than the one being treated,
takes any other medicines or remedies, including non-prescription drugs, vitamins, and herbal therapies, because some may change the way your child’s prescribed medicines work.

Know what medicines your child is on and keep an up-to-date list with you wherever you go. If any other caregivers (babysitters, teachers, and activity group leaders) will be giving your child medicine, make sure that the caregiver has this information and exact instructions on how to give it.

For more information about any medication, speak to your child’s cardiologist, pharmacist, or nurse.

Getting medications for your child

Most local pharmacies carry the more common drugs your child may need. Some specialized medicines may only be available at hospital pharmacies. Call ahead before going to your pharmacy to ask if they have the medicine prescribed for your child.

It is a good idea to use the same pharmacy for all of your medication needs. This helps your pharmacist get to know your child’s needs and makes sure that all your child’s medications can be safely used together.

Storing your child’s medications

Keep medicines away from heat, sunlight, and moisture.
Keep medicines in the fridge ONLY if told to do so.
Check expiry dates. For proper disposal, return any expired medicine or medicine that is no longer needed to the pharmacy.

Storing medication safely

Keep all medicines out of the reach of children.
Keep all medicines tightly capped in their original containers with childproof lids.
Do not mix different medicines in one container.
Do not use your child’s medicines for any other family member.
Keep the phone number of the poison control centre by the telephone in case of an accidental overdose.

OVER-THE-COUNTER MEDICINES
Talk to your pharmacist before buying any over-the-counter medicines for your child, such as cough and cold remedies.

Giving medications

Act as if medicine is part of the normal daily routine. Be positive, firm, and consistent with your child when giving medicine—this will help your child understand its importance.

It can be helpful to give your child a choice, such as what kind of juice to have afterwards. For young children, you may need to have a firm approach, and toddlers will likely need to be held in your arms while you give the medicine.

Some tablets can be crushed or cut in half to make them easier to swallow. Check with your pharmacist to see if this is okay for each specific medicine. Tablets (whole, cut, or crushed) can also be put in ice cream or jam. Use a small amount of food to make sure your child gets all of the medicine.

For unpleasant-tasting medicines, have your child suck on ice cubes or a Popsicle just before taking the medicine. This helps to numb the mouth and taste buds and hide the flavour.

Liquid medicines can be given in a spoon or syringe. Some children will automatically place the tip of an oral syringe into their mouths. Gently depress the plunger a little at a time to allow your child to swallow.

Some children prefer to take medicine from a spoon. If so, measure it with the syringe and then empty the liquid onto a spoon before giving it.

Small rewards can be helpful in encouraging children to take medicines, particularly when it is new medicine.

Tips

Ask your pharmacist if they can provide liquid compounds for tablet medicines to make administering medication easier.
Give medicine exactly as prescribed and for the length of time stated by the doctor. For non-prescription medicines, follow the instructions on the label unless told otherwise by your child’s doctor, pharmacist, or nurse.
Try to give the medicine to your child at the same time every day. To help you remember, choose times that are part of your child’s daily routine.
Refill prescriptions before your supply runs out, especially if you are going out of town or there is a public holiday when clinics and pharmacies may be closed.

TIME-SAVING TIP
If your doctor has prescribed a refill, you can call your pharmacy ahead of time to reorder. Your pharmacist can then have the prescription ready for pickup when you need it. Also check if your pharmacy will deliver prescriptions, another time-saving and stress-reducing tactic.

Giving medications with an oral syringe

Medications are often given in liquid form because babies and children can swallow liquids more easily. Children’s doses are so small that they cannot fit into tablets or capsules.

To make sure that your child gets the right dose, it is important to measure your child’s medicine accurately. The nurse or pharmacist can show you exactly how much medicine to give your child.

There are several tools to help you do this:

oral syringes
medication measuring spoons (available at the pharmacy; don’t use your kitchen measuring spoons)
medication measuring cups (available at the pharmacy)
graduated stoppers

How to use an oral syringe

Pour a small amount of liquid medicine into a small clean cup.
Press down the plunger completely on the syringe.
Place the tip of the syringe into the liquid.
Holding the syringe firmly in one hand, use the other hand to pull the syringe plunger upwards.
Fill the syringe over the amount prescribed by a small amount.
Press down on the plunger until it reaches the marking on the barrel for the amount prescribed.
Remove the syringe from the liquid.
Make sure your child is sitting upright.
Place the syringe between the child’s cheek and gum.
Press down slowly on the plunger. Give small amounts at a time so that your child has time to swallow.
When all the medicine has been given, rinse both parts of the syringe and dry them with a clean towel.
Give your child a small drink of water or juice afterwards to rinse the mouth and wash the medicine down.

MEASUREMENTS
Kitchen teaspoons and tablespoons vary greatly in the amount they measure. Do not use them to measure medicines!

What to do if your child vomits

Repeat the dose only if your child vomits immediately after the medicine is given. Wait 10 minutes before repeating the dose to allow your child’s stomach to settle.

If your child vomits more than 15 minutes after the dose has been given, do not repeat it. Continue with your usual schedule. If you are unsure what to do, call your clinic nurse for instructions.

Call your doctor or clinic nurse if your child vomits with successive doses or for a few days in a row.

What to do if your child misses a dose of medication

Give the forgotten dose as soon as you remember. If it is more than halfway to the next dose before you remember, skip the missed dose and carry on as usual afterwards. Never give a double dose unless your doctor has advised you otherwise.

On Sunday I could imagine him walking, skipping, running, and even heading off to school. Today he has far less energy. I must keep in mind that it is truly one day at a time. What a crazy rollercoaster ride. —PARENT

Remembering medication schedules

It can be helpful to have a calendar to remind you when the medications are due and when they are given. Parents and older children can use the “My Child’s Medications List” form in Appendix B to help track all of this information.

Using weekly pill organizers or pre-setting alarms on phones are other helpful reminders for when medicines should be taken. Both of these reminders are also useful for older children who are learning to be responsible for their own pills.

Finding trustworthy online resources

The internet is useful for getting information quickly, but you can also find incorrect or misleading information. Anyone can put information online, so it is important to make sure the information you are getting is correct and applicable.

If you find information that interests you, test the quality of it first by asking questions:

Can you tell who made the website and why?
Does the main purpose of the site appear to be to provide information? Or is it pushing specific points of view or trying to sell products?
Is the website hosted or managed by a credible source, like a
- well-known health organization, such as Heart & Stroke or the Western Canadian Children’s Heart Network;
- university medical school, such as Johns Hopkins;
- government agency, such as Health Link BC; or
- professional organization, such as the Canadian Cardiovascular Society?
Does the author include their medical education and/or professional background?
Does the site have a warning or disclaimer of any kind? For example, if the author has no medical credentials, is that clearly stated?
Do they warn you that the information should not be used to diagnose or treat a health problem?
Do they advise you to talk to your doctor? (Most reputable health sites will.)
Does the information seem legitimate and do they list the source of the information? Is the source of that information reputable?
Does the page or website link to other websites that are credible?
Is the site current? Does it say when it has been updated? Has it been updated in the past few months? (If the website is not updated on a regular basis, the information may be outdated.)
Are there any misspellings, broken links, or other mistakes that make you question the site’s overall quality?
Is there contact information available so that you can ask questions or make comments?

Use common sense when you evaluate a site. Some of the best sites will not meet all of the qualifications listed above, and some of the worst will. If you aren’t sure about a particular website based on your evaluation, move on and find one that has a clearer origin and credibility.

If you receive conflicting information, note the name and address of the site and discuss it with your cardiologist or a member of your health care team. They will be able to tell you whether the site is trustworthy and if the information applies to your child’s situation.

Helpful websites

The following websites may be helpful to you and your family:

BC Children’s Hospital
bcchildrens.ca

Boston Children’s Hospital
childrenshospital.org/conditions-and-treatments/conditions/congenital-heart-defects

Children’s Heart Network
childrensheartnetwork.org

Children’s Hospital of Philadelphia
chop.edu/centers-programs/cardiac-center

Cincinnati Children’s Hospital
cincinnatichildrens.org/patients/child/encyclopedia

Congenital Heart Information Network
facebook.com/TCHIN.org

Heart & Stroke
heartandstroke.ca

Johns Hopkins Medicine
hopkinsmedicine.org/health/conditions-and-diseases/congenital-heart-defects

Mended Little Hearts
mendedhearts.org

The Royal Children’s Hospital Melbourne
rch.org.au/cardiology/heart_defects/

Western Canadian Children’s Heart Network
westernchildrensheartnetwork.ca

» Go to Chapter 4: Preparing