Understanding Fast Heart Rates in Children: Sinus Tachycardia versus Supraventricular Tachycardia (SVT)

What Is Tachycardia?

Tachycardia means the heart is beating faster than it should for a patient’s age or activity level.

Two Common Types of Tachycardia

1.) Sinus Tachycardia

This is a normal fast heart rate caused by the body’s response to things like:

• Exercise or activity.
• Fever or illness.
• Emotions like anxiety or excitement.
• Caffeine or energy drinks.

Sinus tachycardia starts and stops gradually. The heart rate varies during the episode and is usually below 180 bpm.

2.) Supraventricular Tachycardia (SVT)

SVT is an abnormal rhythm caused by extra electrical signals in the heart. It differs from sinus tachycardia in that it:

• Starts and stops suddenly.
• Has a steady, fast rate (often over 180–220 bpm).
• Can happen even when resting.

You may feel:

• Like your heart is pounding.
• Dizzy or weak.
• Chest discomfort.
• Lightheaded or nauseous.

How to Tell the Difference

Sinus Tachycardia: Gradual, varies, <180 bpm, can slow down with rest. 

SVT: Sudden, steady, >180–220 bpm, feels like a light switch goes on and then goes off

When to go to the Emergency Department

Go to the nearest ED if your child:

• Has a fast heart rate over 180 bpm for more than 30–60 minutes.
• Feels faint, and the fast rate doesn’t stop.
• Struggles to breathe during the episode.

How is SVT treated?

• Teaching your child to stop episodes with special techniques called Valsalva maneuvers.
• Medications.
• Ablation procedures.

Good News!

Most kids with sinus tachycardia or SVT live healthy lives. Knowing the signs helps keep them safe.