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Supraventricular Tachycardia (cont.)

What Happens to the Heart's Electrical Activity in Supraventricular Tachycardia?

In supraventricular tachycardia, the heart rate is sped up by an abnormal electrical impulse starting in the atria.

  • The heart beats so fast that the heart muscle cannot relax between contractions.
  • When the chambers don't relax, they may not contract strongly or fill with enough blood to satisfy the body's needs at rest or especially during times of increased oxygen demand (for example stress, body movements, and walking).
  • Because of the ineffective contractions of the heart, the brain does not receive enough blood and oxygen. People can become light-headed, dizzy, or feel like fainting (syncope).

Supraventricular tachycardia often occurs in episodes with stretches of normal rhythm in between. When tachycardia occurs, it is usually referred to as paroxysmal supraventricular tachycardia (often abbreviated PSVT). Supraventricular tachycardia also may be chronic (ongoing, long-term).

List of the Most Common Supraventricular Tachycardia Conditions

The most common rhythms are:

The other supraventricular tachycardias are infrequently or rarely diagnosed.

List of Supraventricular Tachycardia Heart Conditions

The following is a list of conditions that fit under the broad definition of SVT:
  • Sinus tachycardia
  • Inappropriate sinus tachycardia (IST)
  • Sinus nodal reentrant tachycardia (SNRT)
  • Atrial tachycardia
  • Multifocal atrial tachycardia (MAT)
  • Atrial flutter (AF)
  • Atrial fibrillation (A fib)
  • Paroxysmal supraventricular tachycardia (PSVT; also termed AV nodal reentrant tachycardia or AVNRT and AV reentrant tachycardia or AVRT, a subset of PSVT)
  • Junctional ectopic tachycardia (JET)
  • Nonparoxysmal junctional tachycardia (NPJT)

There are two semantic problems in the literature with supraventricular tachycardias (SVTs). From the strict but extremely broad definition, an SVT can be due to any supraventricular cause. Consequently, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia, and even normal exercise-induced tachycardia could fall under this designation. However, many clinicians consider SVT to be only paroxysmal supraventricular tachycardia (PSVT). The terminology may be somewhat confusing, but the large majority of SVTs are usually discussed separately in articles under their specific name (for example, atrial fibrillation). Because the principal SVTs listed above have separate articles devoted to them in eMedicineHealth, this article will be devoted only to paroxysmal supraventricular tachycardia (PSVT).

Medically Reviewed by a Doctor on 9/11/2017

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Patient Comments & Reviews

The eMedicineHealth doctors ask about Supraventricular Tachycardia (SVT, PSVT Symptoms, Causes, and Treatments):

Supraventricular Tachycardia - Symptoms

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Supraventricular Tachycardia - Treatment

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Supraventricular Tachycardia - Causes

If known, what caused your SVT/PSVT?


Read What Your Physician is Reading on Medscape

Paroxysmal Supraventricular Tachycardia »

Supraventricular tachycardia (SVT), a common clinical condition, is any tachyarrhythmia that requires only atrial and/or atrioventricular (AV) nodal tissue for its initiation and maintenance.

Read More on Medscape Reference »


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