Definition

Ventricular tachycardia is an abnormally fast heart rate. The abnormal heart rate originates in one of the heart’s lower chambers (ventricles). It is diagnosed when there are 3 or more beats in succession originating from a ventricle. The heart beats at a rate greater than 100 beats per minute, but less than 200 beats per minute.

Ventricular tachycardia is considered sustained if it lasts more than 30 seconds. When this condition is sustained, the ventricles are not able to fill with enough blood for the heart to keep blood flowing properly through the body. This can result in lowered blood pressure, heart failure, and death.

Causes

Damage to the ventricles can cause ventricular tachycardia. This damage to the heart muscle may be due to conditions like a heart attack or cardiomyopathy.

Risk Factors

Factors that may increase your chance of ventricular tachycardia include:

• Coronary artery disease (CAD)
• History of heart attacks
• Heart abnormalities, such as cardiomyopathy, mitral valve prolapse, valvular heart disease, or ion channel disorders
• Diagnosis of electrical instability
• Sarcoidosis
• Beginning treatment for hypothyroidism
• Use of certain medications, such as antipsychotics or anti-arrhythmic drugs
• Extreme physical or emotional overstimulation
• Low oxygen levels in the blood
• Very high levels of acid in bodily fluids
• Stimulants, such as caffeine, alcohol, or cocaine

Symptoms

Ventricular tachycardia may cause:

• A sensation of the heart beating very rapidly—palpitations
• Feeling lightheaded
• Feeling short of breath
• Fainting
• Chest discomfort
• Pale skin color

Diagnosis

This condition can be challenging to diagnose. Ventricular tachycardia often happens in emergency situations. It must be identified and treated very quickly.

To make the diagnosis, the doctor will order tests, such as:

• Electrocardiogram (EKG)
• Exercise stress test to test the heart’s performance
• Electrophysiology test to study the electrical signals of the heart

Treatment

In an emergency situation, CPR or a defibrillator may be required.

Other treatment options may include:

• Medications to manage high blood pressure or heart rate
• Surgery, such as:
  • Radiofrequency ablation
  • Open heart surgery

If other approaches fail, an automatic defibrillator will be inserted into the heart to deliver shocks as needed to keep the heart rate steady.

Prevention

To help reduce your chance of ventricular tachycardia:

• Take medications to control heart rate and blood pressure
• Get proper treatment for any underlying heart conditions
• Use alcohol and caffeine in moderation
• Take prevention steps to avoid heart disease by maintaining a healthy weight and exercising.
• If you smoke, talk to your doctor about how you can successfully quit.

Heart Rhythm Society http://www.hrsonline.org

Heart and Stroke Foundation of Canada http://www.heartandstroke.com

Ventricular tachycardia (VT). The Merck Manual Professional Edition website. Available at:
http://www.merckmanuals.com/professional/cardiovascular_disorders/arrhythmias_and_conduction_disorders/ventricular_tachycardia_vt.html
Updated September 2013. Accessed December 30, 2014.

Ventricular tachycardia and ventricular fibrillation. New York-Presbyterian Hospital website. Available at:
http://nyp.org/health/ventricular-tachycardia-fibrillation.html
Accessed December 30, 2014.