Supraventricular tachycardia

Overview

Supraventricular tachycardia (SVT) is a condition where the heart suddenly beats very fast — often over 150 beats per minute. It starts in the upper chambers of the heart (the atria) and usually ends on its own or with simple maneuvers. Although it can feel frightening, it is rarely life-threatening.

SVT is fairly common. It affects about 1 in 200 to 1 in 300 people. It can occur at any age but is more often diagnosed in young adults.

SVT can affect people of all ages, including children and older adults. It is slightly more common in women and often begins before age 40.

Symptoms

Common symptoms

• Palpitations — a feeling that your heart is racing or fluttering in your chest
• Dizziness or lightheadedness
• Shortness of breath
• Chest discomfort or a tight feeling
• Fatigue or weakness during an episode

Symptoms in children

• Fast heart rate that may be hard to notice
• Pale or clammy skin
• Irritability or restlessness
• Poor feeding (in infants)
• Sweating without fever

Symptoms in older adults

• Fainting (syncope) or near-fainting
• Chest pain or pressure
• Confusion or feeling unsteady
• Shortness of breath

Causes

Main causes

• Abnormal electrical pathways in the heart that cause the heart to beat rapidly
• Extra electrical connections present from birth (accessory pathways)
• Scar tissue from previous heart surgery, heart attack, or other heart conditions

Risk factors

• Age — more common in young and middle-aged adults
• Being female (slightly higher risk)
• Stress, anxiety, or panic attacks
• Excessive caffeine, alcohol, or nicotine use
• Certain medications or illegal drugs like cocaine
• Overactive thyroid (hyperthyroidism)

When to see a doctor

See a doctor urgently if:

• You have fainted or nearly fainted during an episode
• You have chest pain or shortness of breath with the fast heart rate

Book a routine appointment if:

• You experience frequent or bothersome palpitations
• Episodes last longer than a few minutes or happen several times a week
• You want to learn how to manage or stop episodes

Diagnosis

Your doctor will ask about your symptoms, listen to your heart, and likely order tests to record your heart's electrical activity during an episode.

Tests that may be done

• Electrocardiogram (ECG) — a quick, painless test that records the heart's electrical signals
• Holter monitor — a portable ECG device you wear for 24 to 48 hours to capture episodes
• Event recorder — a device you can activate when you feel symptoms, used for several weeks
• Echocardiogram — an ultrasound of the heart to check for structural problems

What to expect at your appointment

You may be asked to keep a diary of when symptoms occur and what you were doing. Most tests are painless and can be done in a clinic or at home.

Treatment

Treatment depends on how often episodes happen, how severe they are, and how they affect your life. Many people do not need treatment. For those who do, options range from simple self-help techniques to medications or a minimally invasive procedure.

Self-care at home

• Learn and use vagal maneuvers — for example, holding your breath and bearing down as if having a bowel movement, coughing, or splashing cold water on your face
• Avoid known triggers such as caffeine, alcohol, and stress
• Practice relaxation techniques like deep breathing or meditation

Medical treatments

Your doctor may prescribe medicines to help control your heart rate or rhythm. These are called antiarrhythmic or rate-control medications. In some cases, a procedure called catheter ablation may be recommended. This uses a thin tube to find and destroy the tiny area of heart tissue causing the extra electrical signals.

When is surgery considered?

Surgery is rarely needed for SVT. It may be considered if catheter ablation is not effective or not suitable for your situation.

Living with this condition

Most people with SVT lead full, normal lives. Learn to recognize your triggers and practice vagal maneuvers to stop episodes early. Keep a symptom diary to share with your doctor.

Lifestyle tips

• Get enough sleep and manage stress
• Stay well hydrated
• Limit caffeine and avoid alcohol or nicotine if they trigger your symptoms

Diet and exercise

A balanced diet rich in fruits, vegetables, and whole grains is recommended. Regular exercise is good for heart health, but check with your doctor before starting a new routine. Avoid heavy, high-intensity exercise if it triggers episodes.

Mental health and emotional wellbeing

SVT can cause anxiety, especially if episodes are sudden or scary. This is normal. Talking to a counselor or joining a support group can help you cope. Remember that SVT is usually not dangerous.

Prevention

SVT cannot always be prevented, but avoiding your personal triggers and managing stress can reduce how often episodes happen. Learning vagal maneuvers can help stop episodes early.

Complications

If left untreated

• Frequent or prolonged episodes can weaken the heart muscle over time (heart failure)
• In rare cases, very fast heart rates can lead to a stroke if blood clots form (though this is more common with atrial fibrillation)
• Sudden cardiac arrest is extremely rare with SVT

Long-term outlook

With proper diagnosis and management, the outlook for people with SVT is excellent. Many people have long periods without symptoms, and treatments are effective when needed. Most live normal, healthy lives.

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