Sinus tachycardia

What is sinus tachycardia?

Sinus tachycardia is an increase in heart rate that occurs when the heart’s natural pacemaker, the sinus node, sends abnormally quick electrical signals. It’s the cardiovascular system’s normal response to triggers of stress that increase heart rate, such as emotional distress or physical activity. Inappropriate sinus tachycardia becomes a concern when it’s experienced at rest, which could be a sign that there’s an underlying health issue.

Tachycardia is the medical term used to describe a heart rate that exceeds 100 beats per minute. It’s a type of heart arrhythmia. The resting heart rate for children varies by age but is typically higher than adults. For example, infants can have a heart rate between 100 and 150 heart beats per minute, but this gradually decreases with age.

Sinus tachycardia symptoms

Most children don’t experience any symptoms of sinus tachycardia. If they do, symptoms usually don’t last long. Depending on the underlying cause, some physical sinus tachycardia symptoms your child might experience include:

• Chest pain or discomfort
• Difficulty breathing
• Fainting
• Feeling lightheaded or dizzy
• Heart palpitations
• Increased heart rate

Symptoms experienced with sinus tachycardia may also resemble other health problems. If your child is experiencing these potential sinus tachycardia symptoms, schedule an appointment with your child’s doctor. They can help you identify any potential causes  of sinus tachycardia and get your child back to feeling well.

Sinus tachycardia causes

If your child is experiencing sinus tachycardia, it’s typically because their cardiovascular system is reacting to something or is experiencing stress – and that’s a normal reaction. Here are a few precipitating factors that can cause a reaction of sinus tachycardia:

• Alcohol
• Caffeine
• Dehydration
• Drugs
• Exercise
• Fear
• Fever
• Medications
• Nervousness

Sinus tachycardia can also be caused by underlying health issues including anemia, high or low blood pressure, diabetes, congenital heart abnormalities, heart disease or an overactive thyroid (hyperthyroidism). If this is the case, the sinus tachycardia usually will resolve once the medical condition has been treated.

Sinus tachycardia treatment

Most symptoms of sinus tachycardia are short-lived, not life-threatening and resolve on their own without causing further problems. Lifestyle changes including eating a healthy diet, maintaining a healthy weight, getting regular exercise and eliminating physical stressors can help reduce your child’s sinus tachycardia symptoms. Other underlying causes of sinus tachycardia, such as dehydration or anemia, can also be treated by their doctor.

Inappropriate sinus tachycardia (IST)

Inappropriate sinus tachycardia is the term for an increase in heart rate without an underlying cause. In other words, sinus tachycardia isn't triggered by any of the usual causes such as caffeine or exercise, and the person experiencing it doesn’t have an underlying medical condition that would cause it. Inappropriate sinus tachycardia is rare condition typically seen more often in females than males.

Inappropriate sinus tachycardia (IST) symptoms

Inappropriate sinus tachycardia symptoms are very similar to sinus tachycardia symptoms, although they may be more intense because they’re not related to any external triggers. Inappropriate sinus tachycardia symptoms can include:

• Anxiety
• Chest pain or discomfort
• Decreased ability to exercise
• Feeling lightheaded or dizzy
• Headaches
• Heart palpitations
• Shortness of breath
• Tiredness

What causes sinus tachycardia?

With inappropriate sinus tachycardia, the heart rate is above normal even without the presence of any triggers. But when there is a trigger, such as caffeine or exercise, children with inappropriate sinus tachycardia experience an even higher than normal increase in heart rate in response.

Sinus tachycardia causes can include conditions that put excessive strain on the heart such as anemia, high or low blood pressure, diabetes, congenital heart abnormalities, heart disease and an overactive thyroid (hyperthyroidism).

While inappropriate sinus tachycardia is not serious or life-threatening for most people, you should schedule an appointment with your child's doctor to discuss their risk.

Diagnosing inappropriate sinus tachycardia

To diagnose inappropriate sinus tachycardia, your child’s doctor will ask you about your child’s possible sinus tachycardia symptoms and medical history. This includes details about potential precipitating factors, history of illness, history of heart issues, drug or caffeine use, medications and family history. The doctor will also conduct a physical exam to ensure a healthy heart and normal blood pressure.

The doctor may order blood tests and other scans to help identify sinus tachycardia, an unusually fast heartbeat, or other underlying conditions causing the rapid heartbeat. Diagnostic testing for inappropriate sinus tachycardia may include:

• Chest X-ray: A chest X-ray produces an image of your child’s blood-vessels, heart and lungs.
• Echocardiogram: An echocardiogram is an ultrasound of the heart that checks the functionality and structure of your child's heart. It’s useful in identifying problems with the heart valves, heart muscle and blood flow.
• Electrocardiogram (ECG): A sinus tachycardia ECG is a quick and easy way to help identify problems with the heart. It records the electrical signals from the heart to determine if the heartbeat is irregular or if the heart’s pacemaker isn’t working properly. An ECG can also show previous heart failure or heart damage.
• Holter monitor: This device may be recommended for monitoring your child’s heart rate if they have a rapid heartbeat, but an ECG test doesn’t detect anything abnormal. Your child wears the monitor during their regular daily activities and it gives their doctor a full picture of what their heart rate is like throughout the day.

Inappropriate sinus tachycardia treatment

Sinus tachycardia can be treated with medications or ablation procedures.

Medication for inappropriate sinus tachycardia

Sometimes medication or other medical sinus tachycardia treatments are necessary for slowing down the heart rate, especially for children with inappropriate sinus tachycardia. Depending on the underlying cause of sinus tachycardia and medical history, your child’s doctor will determine the best medication to reduce an irregularly fast heart rate if needed.

• Beta blocker medications are useful in managing abnormal heart rhythms by slowing the heart rate, lowering blood pressure and increasing blood flow.
• Calcium channel blockers lower the heart rate by preventing calcium from entering the cells of the heart and arteries, allowing the blood vessels to relax and open.

Catheter ablation treatment for inappropriate sinus tachycardia

If symptoms are more severe and don’t respond to medication, your child’s doctor might consider catheter ablation for sinus tachycardia treatment. Catheter ablation treats abnormally fast heartbeats by inserting a thin tube called a catheter through a blood vessel and into the heart. This sinus tachycardia treatment procedure uses hot or cold radiofrequency energy to stop the electrical pulses that cause an irregular heartbeat.