Ventricular tachycardia

  

 

 

Ventricular tachycardia

Ventricular tachycardia (VT) is a rapid heartbeat that starts in the ventricles.




Causes

Ventricular tachycardia is a pulse rate of more than 100 beats per minute, with at least
three irregular heartbeats in a row.

The condition can develop as an early or late complication of a heart attack. It may also
occur in patients with:

• Cardiomyopathy
• Heart failure
• Heart surgery
• Myocarditis
• Valvular heart disease

Ventricular tachycardia can occur without heart disease.

Scar tissue may form in the muscle of the ventricles days, months, or years after a heart attack.
This can lead to ventricular tachycardia.

Ventricular tachycardia can also be caused by:

• Anti-arrhythmic medications
• Changes in blood chemistry (such as a low potassium level)
• Changes in pH (acid-base)
• Lack of enough oxygen

"Torsade de pointes" is a form of ventricular tachycardia that is often due to
 congenital heart disease or the use of certain medications.
Symptoms 
If the heart rate during a ventricular tachycardia episode is very fast or lasts longer than
 a few seconds. There may be symptoms such as:

• Chest discomfort (angina)
• Fainting (syncope)
• Light-headedness or dizziness
• Sensation of feeling the heart beat (palpitations)
• Shortness of breath

Note: Symptoms may start and stop suddenly. In some cases, there are no symptoms.

Exams and Tests

Signs include:

• Absent pulse
• Loss of consciousness
• Normal or low blood pressure
• Rapid pulse

Ventricular tachycardia may be seen on:

• Continuous ambulatory electrocardiogram (Holter monitor)
• ECG
• Intracardiac electrophysiology study (EPS)
• Loop recorder

Blood chemistries and other tests may be done.

Treatment

Treatment depends on the symptoms, and the type of heart disorder.
 Some people may not need treatment.

If ventricular tachycardia becomes an emergency situation, it may require:

• CPR
• Electrical defibrillation or cardioversion (electric shock)
• Anti-arrhythmic medications (such as lidocaine, procainamide, sotalol,
•  or amiodarone) given through a vein

Long-term treatment of ventricular tachycardia may require the use of oral
anti-arrhythmic medications (such as procainamide, amiodarone, or sotalol).
 However, anti-arrhythmic medications may have severe side effects. Their use
 is decreasing in favor of other treatments.

Some ventricular tachycardias may be treated with an ablation procedure.
Radiofrequency catheter ablation can cure certain tachycardias.

A preferred treatment for many chronic (long-term) ventricular tachycardias
consists of implanting a device calledimplantable cardioverter defibrillator (ICD).
The ICD is usually implanted in the chest, like a pacemaker. It is connected to
the heart with wires.

The doctor programs the ICD to sense when ventricular tachycardia is occurring,
and to administer a shock to stop it. The ICD may also be programmed to send
a rapid burst of paced beats to interrupt the ventricular tachycardia. You may
 need to take anti-arrhythmic drugs to prevent repeated firing of the ICD.

Outlook (Prognosis)

The outcome depends on the heart condition and symptoms.

Possible Complications

Ventricular tachycardia may not cause symptoms in some people. However,
 it may be lethal in other people. It is a major cause of sudden cardiac death.

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911)
 if you have a rapid, irregular pulse, faint, or have chest pain. All of these may
 be signs of ventricular tachycardia.
Prevention

In some cases, the disorder is not preventable. In other cases,
 it can be prevented by treating heart diseases and correcting blood chemistries.

Alternative Names

Wide-complex tachycardia; V tach; Tachycardia - ventricular