Wide complex tachycardia is a general term that refers to conditions that cause an unusually fast heart rate and a particular pattern on an EKG.

Tachycardia is when your heart beats unusually fast, generally defined as over 100 beats per minute (bpm) at rest.

Wide complex tachycardia is a group of conditions that cause tachycardia and an unusually long part of your heartbeat called the QRS complex. Healthcare professionals can visualize the QRS complex on a printout created by an EKG.

Doctors divide tachycardia into three types:

  • Ventricular tachycardia: This is if the problem originates in your bottom heart chambers.
  • Supraventricular tachycardia: This is if the problem originates above these chambers.
  • Sinus tachycardia: This is if the problem originates from a bundle of cells called the sinoatrial node.

Wide complex tachycardia can either be supraventricular or ventricular in origin.

Read on to learn more about wide complex tachycardia, including its causes and risk factors.

Your heart has a complex system of creating and spreading electrical activity. This electrical activity allows your heart to beat at a regular rhythm.

Wide complex tachycardia develops when something disrupts the production and dispersion of this electrical activity. It can develop for many reasons, including:

  • structural differences in your heart
  • ischemia to the heart
  • heart inflammation
  • metabolic disturbances, or abnormal electrolytes, like high potassium or low magnesium
  • medications that block sodium channels
  • a rapid heart rate due to a pacemaker
  • drug overdose or toxicity

Wide complex tachycardia results from ventricular tachycardia in about 80% of cases.

Ventricular tachycardia can be sustained or non-sustained. It’s sustained if it lasts longer than 30 seconds or requires treatment within 30 seconds. It’s non-sustained if it lasts between three heartbeats and fewer than 30 seconds.

People with non-sustained ventricular tachycardia might not have any symptoms. But people with sustained ventricular tachycardia might have:

Doctors broadly divide wide complex tachycardia into two types. Supraventricular tachycardia originates above the bottom chambers of your heart, while ventricular tachycardia originates in the bottom chambers of your heart.

The term wide complex tachycardia refers to any condition that causes a heartbeat over 100 bpm and a QRS complex longer than 120 milliseconds. A QRS complex is a feature of an EKG reading. It appears like a spike on an EKG. Typically, it lasts less than 120 milliseconds.

Ventricular tachycardia is always “wide.” Supraventricular tachycardia is only wide when there’s also some conduction delay in the heart’s electrical conduction system.

Doctors can also classify wide complex tachycardia as either stable or unstable depending on whether emergency signs and symptoms are present.

People with unstable wide complex tachycardia may develop emergency symptoms, such as:

It’s important to contact a doctor if you believe you may have an atypical heart rate or if you’ve been experiencing symptoms like heart palpitations or shortness of breath without a known cause.

Heart palpitations have many causes, some of which are minor. However, it’s best to rule out more serious conditions.

Medical emergency

Call the emergency medical services or go to the nearest emergency room if you or somebody you’re with develops emergency symptoms, like:

  • sudden collapse
  • confusion
  • blue skin or paleness
  • chest pain
  • difficulty breathing

The main test that doctors use to diagnose wide complex tachycardia is an EKG to measure the electrical activity of your heart.

You may also receive other tests, such as:

Treatment for wide complex tachycardia depends on whether your condition is stable or unstable. Minor cases might not need treatment, but your doctor may want to examine you regularly.

Unstable wide complex tachycardia needs immediate emergency treatment, which might include:

Long-term management might include:

Ventricular tachycardia is the most common cause of wide complex tachycardia.

People with ventricular tachycardia and a history of cardiovascular disease are at a higher risk of sudden cardiac death than people with ventricular tachycardia without underlying heart problems. People who get prompt treatment have the best chance of having a good outcome.

Many people without underlying heart disease have an excellent outlook and never develop complications.

In some cases, wide complex tachycardia may develop as a complication of another type of heart disease, such as a heart attack. You can minimize your risk of having a heart attack by:

Here are some frequently asked questions people have about wide complex tachycardia.

What does wide complex tachycardia indicate?

Wide complex tachycardia suggests a problem with your heart’s electrical activity. Some conditions that cause wide complex tachycardia aren’t serious, while others can be life threatening.

Is wide complex tachycardia dangerous?

Wide complex tachycardia can be stable or unstable. Unstable wide complex tachycardia can lead to sudden cardiac death. Ventricular tachycardia, particularly if sustained, can be life threatening.

What’s the difference between wide complex tachycardia and V-tach?

Ventricular tachycardia, or V-tach, is a type of wide complex tachycardia. Wide complex tachycardia can originate in the heart’s upper chambers when conduction is slowed in part of the heart’s electrical system (supraventricular tachycardia with aberrancy), or it can originate in the lower chambers (ventricular tachycardia).

Wide complex tachycardia is a general term that refers to conditions that cause an unusually fast heart rate and a particular pattern on an EKG reading called a wide QRS complex. A wide QRS complex is when the part of an EKG reading correlating with the contraction of the bottom of your heart exceeds 120 milliseconds.

Wide complex tachycardia can be stable or unstable. People with unstable wide complex tachycardia are at risk of sudden cardiac death if they don’t get prompt treatment for their condition. Stable wide complex tachycardia might not need treatment, or medications and surgery might be necessary.