Heart Racing? Why Your Heart Is Over-Firing (SVT) & Medical Next Steps

If your heart suddenly starts racing, pounding, or fluttering out of nowhere, it can feel alarming. One possible cause is SVT, short for supraventricular tachycardia. SVT is a common heart rhythm condition that causes episodes of abnormally fast heartbeats.

While SVT is often not life-threatening, it is not something to ignore. Understanding what's happening in your body — and knowing when to seek care — can help you respond calmly and confidently.

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What Is SVT?

SVT (supraventricular tachycardia) is a condition where your heart suddenly beats much faster than normal due to abnormal electrical signals in the upper chambers of the heart (the atria).

A normal resting heart rate for adults is typically 60–100 beats per minute. During an episode of SVT, the heart rate can jump to:

• 150–250 beats per minute
• With a sudden start
• And a sudden stop

The word "supraventricular" means the abnormal rhythm starts above the ventricles (the heart's lower chambers). "Tachycardia" simply means fast heart rate.

SVT episodes may last:

• A few seconds
• Several minutes
• Or, in some cases, hours

Some people experience SVT once. Others have recurring episodes.

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Why Does SVT Happen?

Your heart beats because of carefully timed electrical signals. In SVT, the electrical system misfires. The most common reasons include:

• Extra electrical pathways in the heart (often present from birth)
• A "short circuit" loop in the heart's electrical system
• Overactive electrical triggers in the atria

Certain factors can trigger or worsen SVT episodes:

• Stress or anxiety
• Caffeine
• Alcohol
• Dehydration
• Smoking
• Stimulant medications
• Thyroid problems
• Lack of sleep

In many cases, SVT occurs in otherwise healthy people with structurally normal hearts.

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Common Symptoms of SVT

SVT symptoms often begin suddenly. Many people describe it as a "switch flipping."

Typical symptoms include:

• Rapid heartbeat (palpitations)
• Pounding in the chest
• Fluttering sensation
• Lightheadedness
• Dizziness
• Shortness of breath
• Chest discomfort
• Anxiety during the episode
• Neck pulsations

Less commonly, SVT may cause:

• Fainting (syncope)
• Severe chest pain
• Extreme shortness of breath

If you experience chest pain, fainting, or severe symptoms, seek urgent medical care immediately. While SVT itself is often manageable, these symptoms require prompt evaluation to rule out serious complications.

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Is SVT Dangerous?

In most healthy individuals, SVT is not immediately life-threatening. However, that does not mean it should be dismissed.

Repeated or prolonged episodes can:

• Lower blood pressure
• Reduce blood flow to the brain
• Cause fainting
• Strain the heart over time

In people with underlying heart disease, SVT may carry greater risk. That's why a proper medical evaluation is essential.

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How Is SVT Diagnosed?

Diagnosis typically involves documenting the abnormal rhythm. Since SVT often comes and goes, your doctor may recommend:

• Electrocardiogram (ECG or EKG) – records heart rhythm
• Holter monitor – worn for 24–48 hours
• Event monitor – worn for weeks to capture episodes
• Blood tests – to check thyroid function and electrolytes
• Echocardiogram – ultrasound to evaluate heart structure

Because SVT episodes can feel similar to anxiety or panic attacks, proper testing is important. A racing heart is not always "just stress."

If you're experiencing unexplained heart racing or palpitations and want to understand whether your symptoms align with Supraventricular Tachycardia, a free online symptom checker can help you assess your condition before your doctor's appointment.

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What Happens During an SVT Episode?

When SVT starts, the heart's electrical system gets stuck in a fast loop. Instead of following the normal signal path, it cycles rapidly.

You may notice:

• A sudden jump in heart rate
• A strong pulse in your chest or throat
• Difficulty catching your breath

Episodes often stop as suddenly as they start.

Some people learn physical techniques (called vagal maneuvers) to help slow the heart rate. These include:

• Bearing down as if having a bowel movement
• Splashing cold water on the face
• Coughing forcefully

These techniques stimulate the vagus nerve, which can sometimes interrupt the abnormal rhythm. However, they should only be attempted after a doctor explains how to do them safely.

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Treatment Options for SVT

Treatment depends on:

• How often episodes occur
• How long they last
• How severe symptoms are
• Whether underlying heart disease is present

1. Observation

If SVT episodes are rare and mild, your doctor may simply monitor the condition.

2. Medications

Doctors may prescribe medications to:

• Slow heart rate
• Prevent future episodes
• Stabilize heart rhythm

Common categories include beta-blockers or calcium channel blockers.

3. Emergency Treatment

If SVT does not stop on its own, emergency care may involve:

• Intravenous medications
• Electrical cardioversion (a controlled shock to reset rhythm)

This is typically reserved for sustained or unstable episodes.

4. Catheter Ablation

For frequent or severe SVT, catheter ablation may be recommended.

This minimally invasive procedure:

• Uses thin tubes inserted through blood vessels
• Identifies the abnormal electrical pathway
• Destroys (ablates) the small area causing the problem

Ablation has a high success rate and can permanently cure many types of SVT.

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When Should You Seek Immediate Medical Care?

Call emergency services or seek urgent care if you experience:

• Chest pain
• Fainting
• Severe shortness of breath
• Confusion
• A heart rate that stays above 150 bpm and does not slow

Even if symptoms improve, follow up with a doctor. Recurrent SVT should always be evaluated.

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Can SVT Be Prevented?

You may not be able to fully prevent SVT, especially if caused by structural electrical pathways. However, you can reduce triggers:

• Limit caffeine and alcohol
• Stay hydrated
• Manage stress
• Avoid stimulant medications unless prescribed
• Get adequate sleep
• Treat thyroid disorders promptly

Lifestyle adjustments often reduce episode frequency.

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Living With SVT

Many people with SVT live full, active lives. The key is awareness and medical guidance.

Important steps include:

• Tracking your episodes
• Not ignoring worsening symptoms
• Following up regularly with your healthcare provider
• Discussing long-term treatment options if episodes increase

Avoid self-diagnosing. A racing heart can have many causes, including atrial fibrillation, anxiety disorders, thyroid disease, and other arrhythmias. Proper testing is critical.

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The Bottom Line

SVT is a common heart rhythm condition that causes sudden episodes of rapid heartbeat. While often not immediately dangerous, it deserves proper medical evaluation.

If your heart has been racing without clear explanation:

• Pay attention to when it happens
• Note how long it lasts
• Seek medical evaluation
• Use a free AI-powered symptom checker to learn more about Supraventricular Tachycardia and prepare for your medical consultation

Most importantly, speak to a doctor about any heart-related symptoms — especially if they involve chest pain, fainting, or severe shortness of breath. Heart rhythm issues can sometimes signal serious conditions, and only a qualified medical professional can provide a proper diagnosis and treatment plan.

A racing heart can feel frightening. But with the right evaluation and care, SVT is often highly manageable — and in many cases, treatable or even curable.