What is ventricular tachycardia (VT)?

Ventricular tachycardia (VT) is a fast, abnormal heart rhythm (arrhythmia). It starts in your heart’s lower chambers. These are called ventricles. It's defined as three or more heartbeats in a row, at a rate of more than 100 beats a minute. VT can be deadly if it lasts for more than a few seconds at a time. Sustained VT is when it lasts for more than 30 seconds. It can also be linked to a blood flow issue, such as abnormal blood pressure. Nonsustained VT lasts less than 30 seconds.

With rapid heartbeat, your heart can't fill with blood between beats. This affects blood flow to the rest of your body.

What causes VT?

VT happens from:

• Reentry. This is an abnormal heart circuit that's triggered in the muscle of the ventricle.

• Automaticity. This is an abnormal ventricular muscle that is self-activated, or has no trigger.

VT can occur in a heart that is otherwise healthy and has a normal structure. It can occur due to damage or scarring in the heart from past heart disease. This is more serious and can be life-threatening. But if VT happens in a heart that has a normal structure, it's not serious if it stops on its own. Any heart problem that damages and scars the ventricle muscle can cause VT. It can also be caused by inherited or genetic disorders. These include long QT syndrome or Brugada syndrome.

Who is at risk for VT?

VT is often linked to other problems. Damaged heart muscles can cause abnormal electrical circuits that leaad to VT. You may be more at risk for VT if you have:

• Abnormal heart valves.

• Cardiomyopathy.

• Heart failure.

• Coronary artery disease.

• Heart attack.

Some genetic diseases can lead to VT. These include: 

• Conditions that make it hard for the heart to pump blood. An example is hypertrophic cardiomyopathy.

• Diseases that can occur inside the heart muscle, such as sarcoidosis. This is caused by inflammation.

• Diseases that change the electric properties and heart rhythm. These include Brugada syndrome and catecholaminergic polymorphic VT.

In some cases, VT occurs when there are no other heart problems. This may be seen in self-activating VT.

What are the symptoms of VT?

VT symptoms include:

• Fast heartbeat, or a fluttering feeling in the chest (palpitations).

• Dizziness.

• Lightheadedness.

• Chest pain.

• Neck tightness.

• Shortness of breath.

• Fainting.

• Cardiac arrest.

In some cases, there are no symptoms at all.

How is VT diagnosed?

To find out if you have VT, you may need an electrocardiogram (ECG). This test records your heart rate and rhythm. Your doctor may want to watch your heart’s activity for a longer time. This is done using a Holter monitor or event recorder. VT may be diagnosed in the hospital with heart monitoring called telemetry. It may also be seen and diagnosed from a stress test. Some smartphones along with a recording device can record VT when you're having symptoms.

In some cases, your doctor may think you have VT, but they have not been able to record it. Implantable loop recorders can be used to record your heart rhythm for up to 5 years. These are electronic devices that are about the size of a pinky finger. They're put into the skin near the heart.

In some cases, an electrophysiology study is done to see if VT can be induced. This is done by placing wires in the heart via a vein in your leg.

How is VT treated?

Treatment depends on your symptoms. You may not need treatment if:

• You don’t have heart disease.

• You're not having bad symptoms.

• Your VT episodes don’t last a long time.

If you have symptoms, you might get medicine to control your heart rhythm. This may be a beta-blocker, a calcium channel blocker, or an antiarrhythmic medicine.

For VT that's sustained or life-threatening, you may get an ICD (implantable cardiac defibrillator). The ICD may be used if there's no known cause that can be treated or you have another condition that makes more episodes of VT likely. The ICD is a small device that's put into your chest. It connects to your heart with wires. When an abnormal heartbeat occurs, the ICD can overdrive pace the VT to stop it. Or, if needed, the ICD can send an electric shock to restore your normal heartbeat. Newer ICDs can be put in just below the left armpit. A wire is put in over the breastbone instead of inside the heart.

Some VT may be treated with catheter ablation. This method destroys the abnormal heart tissue that's causing the rapid heartbeat.

What are possible complications of VT?

Some people may have mild symptoms from VT. Or they may have no symptoms at all. But for others, VT can be dangerous. It can lead to fainting, sudden cardiac arrest, or death.

Can VT be prevented?

Prevention focuses on treating the heart problems that cause VT. This may include:

• Taking medicines for heart failure.

• Treating heart artery disease.

• Having surgery to fix heart valve problems.

• Following a heart-healthy diet and exercise plan. These help reduce your risk for some of these problems.

For some people, caffeine or alcohol can trigger VT episodes. Don't use them if they affect your VT.

Living with VT

If you're diagnosed with VT, follow your treatment plan closely. Take all medicines as prescribed. Tell your doctor about any medicines you may be taking for other health problems. Discuss your alcohol, tobacco, or caffeine use with your care team. 

When should I contact my health care provider?

Call 911if:

• You have chest pain or pressure.

• You are short of breath.

• You feel lightheaded, dizzy, or you faint.

• You have rapid heartbeat that won't go away.

Key points about VT

• Ventricular tachycardia (VT) is a fast, abnormal heart rhythm. This may last for only a few seconds or for a longer time.

• VT that lasts for only a few seconds may not need treatment.

• Longer episodes may be dangerous and need treatment and prevention.

• Some diseases that cause heart muscle damage can lead to VT.

• Treatment may include medicines, ablation therapy, or an ICD to check and correct your heartbeat.

• Call 911 if you have chest pain or pressure, shortness of breath, fainting, rapid heartbeat that won't go away, or if you feel lightheaded or dizzy.

Next steps

Here are some tips to help you get the most from a visit to your provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you have.

• Bring someone with you to help you ask questions and to recall what your provider tells you.

• At the visit, write down the name of a new diagnosis. And write down any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why you're getting a new medicine or treatment and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why your provider recommends a test or procedure and what the results could mean.

• Know what to expect if you don't take the medicine or have the test or procedure.

• If you have a follow-up visit, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.