Common Heart Issues in Kids & How They're Diagnosed

The information provided in this blog is for educational and informational purposes only. It is not intended as medical advice, diagnosis, or treatment. You’re sitting in a pediatric cardiology office, your child fidgeting beside you, heart monitor wires peeking from under their shirt. The pediatrician said they “heard something,” and now you’re here. Google has already scared you half to death, and now you’re trying to smile through the anxiety because your kid is watching. You want straight answers. You want to know what’s going on and what happens next. You want to be ready—but everything feels uncertain.

Heart problems in children can be terrifying to think about. But knowing what they are and how they’re usually found can make things feel a little more manageable. Understanding what comes next gives you tools to advocate for your child. And when you can bring the hospital experience into playtime in a way that makes it feel less scary? That’s a big win—for you, and for your child.

What Are the Most Common Heart Conditions in Kids?

Some heart issues show up right after birth. Others don’t make themselves known until later in childhood, when a kid is more active or starts growing quickly. The good news is many are manageable. Some are even harmless. Here are a few conditions doctors see most often:

Heart Murmurs

These are extra sounds the heart makes as it pumps blood. They can be “innocent,” meaning there’s no structural problem, or “pathologic,” meaning there is a defect in the heart that needs follow-up. Murmurs are often the first clue that leads to further testing.

Congenital Heart Defects (CHDs)

These are structural problems in the heart that a child is born with. They might affect the walls, valves, or blood vessels. Some CHDs are mild and never need surgery. Others require intervention early in life.

Arrhythmias

These are irregular heart rhythms—either too fast, too slow, or uneven. Kids can have them due to underlying conditions or sometimes with no clear cause at all.

Kawasaki Disease and Myocarditis

These are inflammatory conditions that can affect the heart muscle or vessels. Kawasaki can lead to complications in the coronary arteries if not treated early. Myocarditis might follow a viral infection and can mimic other illnesses at first.

Cardiomyopathy

This is when the heart muscle becomes weak or enlarged. It’s less common, but doctors take it seriously because it can affect how well the heart pumps blood.

How Do Doctors Find Out What’s Going On?

Pediatric heart issues often come to light in unexpected ways: a fainting episode during soccer practice, a checkup where something “doesn’t sound quite right,” or a newborn screening that flags low oxygen levels. Once a concern is raised, here’s how the process usually unfolds:

Physical Exam and Family History

Doctors start by listening carefully. They use a stethoscope to check for murmurs or irregular rhythms and ask about symptoms like fatigue, feeding issues, fainting, or chest pain. Family history matters too—conditions like arrhythmias or cardiomyopathy can sometimes run in families. If a child has started avoiding physical play or acting more tired than usual, that may be a subtle sign something’s off.

When children are familiar with medical play support tools like pretend stethoscopes or chest stickers, these early experiences can feel less intimidating. Familiarity with the tools helps children feel more at ease, and parents might notice behavior changes during play that point to discomfort or fatigue.

Electrocardiogram (ECG or EKG)

This quick, painless test records the heart’s electrical activity. Electrodes are placed on the chest, arms, and legs, and a machine measures the rhythm and speed of the heartbeat. It helps spot arrhythmias or unusual electrical patterns. This is a first-line test when something seems unusual during a physical exam.

Incorporating toy versions of ECG’s or monitors into medical play can ease anxiety if this test becomes necessary. Kids who’ve practiced with playful versions may feel less threatened and more cooperative during the real test.

Echocardiogram (Heart Ultrasound)

An echocardiogram is one of the most important tools for diagnosing heart problems. It uses ultrasound to show a moving picture of the heart. Doctors can see how blood flows, how the valves work, and whether the heart chambers are the right size and shape. It gives detailed information about structural problems like CHDs.

This test requires children to lie fairly still, which can be challenging. Role-playing with plush dolls or story-driven prep using toy ultrasound wands can help children understand what’s coming and stay calm during the process.

Chest X-ray

A chest X-ray can show if the heart is enlarged or if there’s fluid buildup in the lungs, both of which may point to heart failure or cardiomyopathy. It’s a fast scan that gives a broad view of the heart and lungs.

Pulse Oximetry

Pulse ox clips onto a child’s finger or toe and measures how much oxygen is in the blood. Low readings can suggest heart or lung problems. It’s one of the first tools used in newborn screenings and often used again if a child has blue lips, breathlessness, or fatigue.

Because it’s painless and non-invasive, many children tolerate it well. Still, introducing a toy version during pretend play helps it feel familiar and even fun when it matters most.

Holter Monitor or Event Monitor

If your child has symptoms that come and go—like feeling dizzy, faint, or having palpitations—your doctor may recommend a wearable monitor. These devices record the heart’s rhythm over time. Holter monitors typically record for 24 to 48 hours, while event monitors track symptoms over weeks.

Kids often dislike the stickers and wires, and wearing a device all day can feel intrusive. That’s why it helps to include play-based versions of these tools in a child’s routine beforehand. Pretending with medical dolls who wear monitors, or using sticker sets that mimic electrodes, can turn a stressful experience into one they feel more in control of.

Stress Testing and Cardiac MRI

Older kids and teens who experience symptoms while active might do a stress test. This usually involves walking or jogging on a treadmill while hooked up to monitors. Doctors watch how the heart responds to exertion. A cardiac MRI offers a very detailed image of the heart and can show more than an echo in certain cases. It’s usually used when a child has a complex condition or if doctors need a clearer picture of the heart’s structure and function.

Both procedures are more advanced and might happen in a hospital or specialty clinic. Preparing your child ahead of time with simple role-play or visual schedules can make a big difference in how they cope.

What to Do After a Diagnosis

Hearing that your child has a heart condition can feel like your world has tilted. But having a name for what’s going on gives you power. It allows you to make a plan.

Ask your child’s cardiologist to write down the diagnosis, what it means, and what comes next. Keep track of symptoms, medications, and test results in one place. If you’re not sure what a term means, ask again. You’re allowed to ask until it makes sense.

Support your child emotionally, too. Children often sense when something is wrong, even if you haven’t explained everything. Let them ask questions. Let them play it out. Use tools like our inclusive medical toys to explore tests and treatments through storytelling and pretend care. When children get to be the doctor, or help a doll get an EKG, they build confidence. And when they see dolls or characters with heart conditions like theirs, it tells them they belong.

When to Worry, and When to Watch

Not every flutter or skipped beat is cause for alarm. But if your child is experiencing chest pain, dizziness, fatigue, fainting, or changes in color around the lips and fingertips, follow up quickly. If you have a newborn, ask if pulse oximetry screening was done before discharge. It can catch serious CHDs early—but not every hospital includes it as a routine test yet.

For children already diagnosed, stay in close contact with your care team. Track symptoms and note any changes in energy or behavior. Keep a clear emergency plan and make sure all caregivers, schools, and activity leaders know your child’s needs. Tools like medical ID bracelets or laminated instruction cards in backpacks can be useful.

Bringing Medical Play Into the Picture

At The Butterfly Pig, we design toys with the real needs of children in mind. Our pretend EKG stickers, oxygen clips, and toy monitors are more than props—they’re tools for building understanding. When children are invited to play with these tools, they gain language and context for their experiences. They learn to name their fears. They learn to ask questions. And that’s where empowerment starts.

Representation also matters. Seeing toys that look like them—with surgical scars, chest devices, or visible health differences—reminds kids that their story isn’t strange or shameful. It’s part of who they are. And they are worthy of care, attention, and joy.

You Are Not Alone

If you’re reading this because your child is being tested or has just been diagnosed, we want to say this clearly: you’re not alone. It’s okay to be scared. It’s okay to feel overwhelmed. What matters most is that you keep showing up. The good news is that many heart conditions in kids are treatable, and children with these conditions often grow up to thrive. With the right care, the right tools, and a supportive community around you, your child has every chance to live a full, wonderful life.

You don’t need to be perfect. You just need to be present. Keep asking questions. Keep creating moments of calm and connection. Keep playing, even on the hard days. Because play isn’t just a way to pass the time. It’s how kids make sense of their world. And with the right kind of play, they learn that even in a hospital gown, they are brave, capable, and loved.

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