Ventricular Tachycardia

What is ventricular tachycardia?

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

At rest, a normal heart rhythm is between 50 and 100 heartbeats a minute, and normally an electrical impulse in the upper right chamber of the heart (the right atrium) starts each heartbeat. In most cases of VT, the heart beats between 120 and 170 times a minute, and the heartbeat starts in the lower chambers (ventricles) of the heart rather than the right atrium.

There are 2 types of VT:

• If the fast heart rate lasts more than 30 seconds or you have lightheadedness or fainting with the fast heartbeats, you have sustained ventricular tachycardia. Most people with sustained VT have a higher risk of sudden death. They should always be treated.
• If the fast heart rate lasts less than 30 seconds and you do not have any symptoms of lightheadedness or fainting, it is called nonsustained ventricular tachycardia. This type of VT is less serious. However, if you have nonsustained VT and a weakened heart muscle from a previous heart attack, you may have a higher risk of sudden death.

How does it occur?

A short circuit in the heart's conduction pathway can cause the fast heartbeat. A short circuit can result from a slowed heartbeat impulse. The impulse may be slowed by an abnormal heart muscle, medicine you are taking, or damage from a heart attack.

VT may occur if:

• You have had a heart attack that hurt the heart's ability to pump. You may not get VT until weeks or months after the heart attack.
• You have severe heart failure, which means that your heart cannot pump enough blood to meet your body's needs.
• You have idiopathic dilated cardiomyopathy (IDCM), which is a disease that causes the heart to get bigger and not pump properly.
• You have hypertrophic cardiomyopathy (HCM), which is a disease that causes the walls of the heart to become thick and stiff. The thickening may make it harder for the heart to pump blood well.

What are the symptoms?

Most people with VT have symptoms such as:

• weakness and sweatiness due to low blood pressure
• chest pain
• fainting
• a pounding feeling in the chest
• shortness of breath.

How is it diagnosed?

An electrocardiogram (EKG or ECG) is the most helpful test. It records the electrical activity of the heart. An ECG done during a spell of tachycardia almost always shows the abnormal rhythm. If you do not have tachycardia during a brief ECG test, a 24- or 48-hour ECG using a portable recorder may catch the abnormal rhythm. The portable recorder lets you put a signal on the tape when you feel symptoms.

Sometimes a special test called an 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?

VT may be treated with:

• an implantable cardioverter-defibrillator (ICD), which is a device that recognizes the tachycardia and shocks the heart back into a normal rhythm
• medicine, such as sotalol or amiodarone.

Also, the conditions that might cause VT are treated. If your heart does not pump well, your healthcare provider will prescribe medicines to help it pump better.

How long do the effects last?

If you have sustained VT, you may need treatment for the rest of your life. This may also be true if you have nonsustained VT, depending on the results of other tests.

How can I take care of myself?

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

How can ventricular tachycardia be prevented?

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

• Keep a healthy weight.
• Eat a healthy diet.
• Get regular exercise, as recommended by your healthcare provider.
• Do not smoke.
• Have regular medical checkups after age 40.

Take all of the medicines your provider suggests. Sustained VT can sometimes be prevented by medicines.