Automatic Tachycardias

intensive care
intensive care. Martin Barraud/Getty Images

Sometimes cardiac arrhythmias can be caused by the spontaneous generation of abnormal electrical impulses from somewhere within the heart. When these abnormal impulses occur rapidly, tachycardia (a rapid heart rate) occurs. Tachycardias caused by the spontaneous generation of abnormal electrical impulses are called “automatic tachycardias.”


The word tachycardia simply means a heart rate of greater than 100 beats per minute. There are three general causes of tachycardia:

  • Normal tachycardia (or sinus tachycardia) is a normal phenomenon most of us experience each day. It occurs because the sinus node speeds up the rate at which it generates electrical impulses in response to exertion or stress. (There is, however, a type of abnormal sinus tachycardia, called inappropriate sinus tachycardia, or IST.)
  • Reentrant tachycardia is a cardiac arrhythmia caused by an abnormal electrical connection somewhere in the heart that creates a potential circuit. Reentrant tachycardias start and stop suddenly and for no apparent reason, and most often occur in people who are otherwise completely healthy.
  • Automatic tachycardias do not involve an abnormal electrical circuit but instead, are caused by the spontaneous generation of electrical impulses from somewhere other than the sinus node. These arrhythmias are often seen in people who are medically unstable.


In automatic tachycardias, cells in some location within the heart begin producing their own electrical impulses faster than the sinus node does, thus taking over the rhythm of the heart and producing tachycardia.

Automatic tachycardias can be either supraventricular (so-called “automatic atrial tachycardia,” which means that the cells that are "automatically" firing are be located within the atria), or ventricular (“automatic ventricular tachycardia,” in which the abnormal electrical impulses are coming from the ventricles).

In addition, automatic junctional tachycardia can occur when the abnormal impulses arise near the AV node, which is near the "junction" of the atria and the ventricles).

In stark contrast to the reentrant tachycardias, automatic tachycardias are most commonly seen in people who are acutely ill. This is because various types of acute illness may create the conditions necessary for cardiac to produce abnormal electrical impulses.

In particular, automatic arrhythmias tend to occur in people who have acute lung disease (such as pulmonary embolus or pneumonia), acute myocardial infarction (heart attacks), or in people who have various severe abnormalities in their metabolic condition — such as low blood oxygen levels, low potassium or magnesium blood levels, or very high levels of adrenalin.

As a result, automatic tachycardias are most commonly seen in particularly unstable patients in the hospital setting, especially in people who are sick enough to be in intensive care units.

There are exceptions to this common pattern, however. A rare condition called automatic atrial tachycardia (also called “ectopic atrial tachycardia”) can occur in young, otherwise healthy people. Unlike reentrant atrial tachycardia, this condition tends to be persistent instead of intermittent and can lead to tachycardia-induced heart failure. This type of persistent automatic atrial tachycardia is usually treated with ablation therapy.


In general, the most effective treatment for automatic tachycardia is to identify and reverse the underlying medical problem. Once the underlying lung condition, cardiac condition, or metabolic abnormalities are stabilized, the arrhythmia goes away. So in almost all cases, the treatment for automatic tachycardias is to rapidly stabilize the medical disorder that is producing it.

Usually, when a person who has had an automatic tachycardia is healthy enough to leave the hospital, the arrhythmia has already resolved. There is no reason to consider using chronic antiarrhythmic drugs, or other long-term therapy aimed at treating cardiac arrhythmias. Preventing any further arrhythmias is a matter of taking whatever steps are possible to prevent a recurrence of the medical problem that caused the arrhythmia in the first place.

A Word From Verywell

Automatic tachycardias are caused by the spontaneous generation of electrical impulses from somewhere in the heart. They can be thought of as a cardiac arrhythmia due to an “irritation” of cardiac cells, usually as the result of an acute, severe medical condition. In general, these arrhythmias go away when the underlying medical condition is successfully treated, and no long-term antiarrhythmic therapy is required.

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