Non-Sustained Ventricular Tachycardia (NSVT)

NSVT stands for non-sustained ventricular tachycardia. It’s a type of abnormal heartbeat (arrhythmia) in which your heart beats very fast for less than 30 seconds at a time without a significant effect on your blood pressure or loss of consciousness. You may also feel dizzy or like your heart is pounding or flip-flopping in your chest.

To understand NSVT, it may help to learn what each part of the name means:

• Non-sustained: This means each episode doesn’t last long.
• Ventricular: This refers to your ventricles, or lower heart chambers. That’s where the abnormal heartbeats start.
• Tachycardia: This is the medical term for a fast heart rate.

NSVT is harmless in some people but dangerous in others. In general, if your heart is otherwise healthy, you likely don’t have to worry about NSVT. But it may pose some risks if you also have other heart issues. Your healthcare provider will run tests to learn more and make sure you get any needed treatment.

Symptoms of NSVT

NSVT affects each person a little differently. You might have just one or a few episodes of a fast heart rate per day. And each episode may last just a few seconds. It’s possible to feel no symptoms at all during these episodes. But you may have:

• Heart palpitations (most common symptom)
• Dizziness
• The feeling that you’re about to faint

A lack of symptoms doesn’t necessarily mean the condition is less serious. When you’re living with certain forms of heart disease, it’s common to have many episodes of NSVT throughout the day that don’t cause symptoms. Your provider may only know about them if they use a device to monitor your heart’s activity.

NSVT causes

A wide range of problems with your heart’s structure or function can cause or lead to NSVT, including:

• Brugada syndrome
• Cardiomyopathy
• Coronary vasospasm
• Heart attack (past or current)
• Hypertensive heart disease
• Long QT syndrome
• Mitral valve prolapse
• Short QT syndrome
• Unstable angina

NSVT can happen in an otherwise healthy heart for unknown reasons. This is called an “idiopathic” case. But for many people, healthcare providers can pinpoint the cause.

Complications of this condition

Having NSVT may raise your risk for sudden cardiac death if you also have any of the following conditions:

• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Arrhythmogenic right ventricular dysplasia
• Cardiac sarcoidosis
• Cardiac amyloidosis
• Heart failure

Your healthcare provider will talk to you about your risk and how to manage it. The risk of sudden cardiac death is very low if your heart is otherwise healthy.

How doctors diagnose this condition

NSVT is often an “incidental diagnosis.” This means it shows up when providers run tests for other reasons. For example, your provider may notice NSVT patterns when looking for other arrhythmias. Or they may see it on a telemetry monitor when you’re in the hospital. You might be the first to notice NSVT on a smartwatch or another device you use at home.

If your provider suspects you have NSVT, they’ll run further tests to confirm the diagnosis and find the cause. You may need:

• Ambulatory monitoring
• Blood tests
• Cardiac MRI
• CT angiogram or a heart cath
• Echo
• EKG
• Electrophysiology study
• Exercise stress test
• Genetic testing in some situations, like if your provider suspects an inherited condition

Testing can also show exactly where in your ventricles the abnormal heartbeats begin. Knowing whether they start in the same spot each time or in different spots helps them plan treatment. NSVT that starts in different spots each time is typically more dangerous.

How is NSVT treated?

Treatment for NSVT depends on your symptoms and risk for sudden cardiac death. You may not need treatment if your heart is healthy and you don’t have symptoms. But your provider may recommend medicines or procedures if you have symptoms or you’re at risk of serious complications (even without symptoms).

Possible treatments include:

• Medicine like beta-blockers, antiarrhythmic drugs or verapamil to manage your heart rate
• Catheter ablation to destroy tissue that’s causing the abnormal heartbeats
• Implantable cardioverter defibrillator (ICD) to monitor your heart rate and slow it down when needed

When should I see my healthcare provider?

Contact your provider if:

• You have NSVT symptoms
• A device, like a smartwatch, alerts you to any type of arrhythmia, including NSVT
• You have questions or concerns about your treatment plan

Call 911 or your local emergency number if you have chest pain, trouble breathing or fainting.

What can I expect if I have non-sustained ventricular tachycardia?

Your prognosis (outlook) depends on many things, including:

• Where in your ventricles the abnormal heartbeats begin
• How often episodes occur
• Other heart conditions you have

Your healthcare provider will explain what you can expect in your situation. NSVT is usually harmless in people without other heart conditions. But having NSVT along with other heart problems may mean you need certain treatments to lower your risk of complications.