Ventricular Tachycardia

Condition Basics

What is ventricular tachycardia?

Ventricular tachycardia (VT) is a type of fast heart rhythm that starts in the lower part of the heart (ventricles). The heart beats more than 100 beats per minute.

Some forms of VT may get worse and lead to ventricular fibrillation, which can be life-threatening. With ventricular fibrillation, the heartbeats are very fast and irregular. Ventricular fibrillation may cause cardiac arrest. In cardiac arrest, the heart stops pumping blood to the body. Cardiac arrest can cause sudden cardiac death.

What causes it?

Sometimes it is not known what causes ventricular tachycardia (VT). But in most cases, VT is caused by heart disease, such as a previous heart attack, congenital heart disease, hypertrophic cardiomyopathy, dilated cardiomyopathy, or myocarditis. Sometimes VT occurs after heart surgery. Inherited heart rhythm problems, such as long QT syndrome or Brugada syndrome, can also cause VT.

Some medicines can cause ventricular tachycardia. These include antiarrhythmic medicines, other heart medicines, and antibiotics. Less common causes include blood imbalances, such as low potassium levels and other electrolyte imbalances.

Herbal remedies that contain ephedra, also known as ma huang, can trigger VT. Drugs (such as stimulants, like cocaine) also may cause it.

What are the symptoms?

VT may not cause symptoms. When it does, symptoms include feeling dizzy or lightheaded, shortness of breath, and chest pain or pressure. You may also have palpitations. These are an uncomfortable awareness of the heart beating very fast or not in a regular way. Or you may faint or be near fainting.

How is it diagnosed?

Your doctor will do an exam and ask about your health history.

Your doctor will also do an electrocardiogram (EKG, ECG). This is a tracing of the electrical activity of your heart. VT can come and go. It may be hard to capture with an EKG at your doctor's office. So the doctor may want you to wear a heart monitor. It records your heart rhythm over a few days or longer.

You may have lab tests and a chest X-ray.

Your doctor may also recommend other tests.

• Imaging tests, such as an echocardiogram, show the structure of your heart.
• A stress test can show if the heart muscle is getting enough blood or if heart arteries are narrowed.
• An electrophysiology (EP) study can find specific areas of your heart that may be causing the VT.

The results of these tests can help your doctor decide what treatment options you have.

How is ventricular tachycardia treated?

To prevent VT and relieve symptoms, you may take heart rhythm medicines.

Some people may have a catheter ablation. This procedure destroys small areas of heart tissue that cause the irregular heartbeat. It may make VT happen less often. Or it may stop VT from happening again.

Your doctor may recommend a device that can prevent sudden death. It can detect a life-threatening abnormal heartbeat and help restore a normal rhythm. This device might be implanted (ICD, or implantable cardioverter-defibrillator) or worn as a vest.

If you have VT that is not stopping, it is a medical emergency. You may need a shock to try to get your heart back into a normal rhythm. This can be from an automated external defibrillator (AED), by paramedics, or through treatment in an emergency room. A doctor may give you medicines if your condition is stable.