Ventricular Tachycardia

What is ventricular tachycardia?

Ventricular tachycardia (called VT or V tach) is a condition in which your heart beats too fast and its contractions start in the wrong part of the heart.

At rest, the heart normally beats between 50 and 100 times per minute. Tachycardia is a heart rate of more than 100 beats per minute.

Normal heartbeats and rhythm start in the upper right chamber of the heart (the right atrium). VT starts in the lower chambers (ventricles) of the heart. In most cases of VT, the heart beats between 120 and 170 times per minute.

There are two types of VT:

If the fast heart rate lasts more than 30 seconds or there is lightheadedness or fainting, it is called sustained ventricular tachycardia. Most people with sustained VT are at a high risk of sudden death and should always be treated.
If the fast heart rate lasts less than 30 seconds and there are no symptoms of lightheadedness or fainting, it is called nonsustained ventricular tachycardia and is less serious. However, if you have nonsustained VT and have had a heart attack and have a weakened heart muscle, you may be at higher risk of sudden death.

How does it occur?

The heartbeat impulse may be slowed by an abnormal heart muscle structure, some medicines, or damage from a heart attack. Slowing of this impulse causes a "short circuit" in the conduction pathway. The "short circuit" causes the fast heartbeat.

VT may occur in people who have:

a serious heart attack that has damaged the heart's ability to pump. You may not get VT until weeks or months after the heart attack. You have a higher risk for sudden death and need treatment.
severe heart failure, a condition in which the heart is unable to pump enough blood to meet the body's needs.
idiopathic dilated cardiomyopathy (IDCM), a heart muscle disease that causes the heart to enlarge.
hypertrophic cardiomyopathy (HCM), a condition in which the heart muscle becomes so thick that it interferes with the heart's pumping ability and may even block some of the blood flow from the heart.

What are the symptoms?

Most people with VT have symptoms such as:

weakness and sweatiness due to lowered blood pressure
chest pain
passing out
a pounding sensation in the chest
shortness of breath.

How is it diagnosed?

The electrocardiogram (EKG or ECG), a recording of the electrical activity of the heart, is the most helpful test for diagnosing VT. An EKG taken during a spell of tachycardia almost always identifies the abnormal rhythm. If the spells of tachycardia are infrequent, 24- or 48-hour tape recordings of the EKG often catch the abnormal rhythm. The portable recorder allows you to place a signal on the tape if you feel any symptoms.

Sometimes a special test called electrophysiologic study (EPS) is needed to diagnose VT. EPS uses tiny wires inserted into your heart through your veins to study the conduction system and to try to reproduce the VT.

How is it treated?

The conditions that might cause VT are treated. If your heart is pumping poorly, your doctor will prescribe medicines to help it pump better.

VT is usually treated with an implantable cardioverter-defibrillator (ICD). Sometimes medicines are also used. The ICD is a device that recognizes the tachycardia and shocks the heart back into normal rhythm. Sotalol and amiodarone are the most effective medicines.

How long do the effects last?

If you have sustained VT, you will likely need treatment for life.

How can it be prevented?

The best prevention is to have a heart-healthy lifestyle:

Maintain a healthy weight.
Eat a healthy diet.
Get regular exercise, as recommended by your health care provider.
Don't smoke.
Limit caffeine and other stimulants.
Have regular medical checkups after age 40.
Take all the medicines your doctor suggests. Sustained VT can sometimes be prevented by medicines.

Be sure to follow your doctor's instructions. If symptoms start while you are being treated, call your doctor right away.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File CRD3651F.HTM Release 9.0/2006