Supraventricular Tachycardia

• Supraventricular Tachycardia Overview
• Supraventricular Tachycardia Causes
• Supraventricular Tachycardia Symptoms
• When to Seek Medical Care
• Exams and Tests
• Supraventricular Tachycardia Treatment
• Self-Care at Home
• Medical Treatment
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Supraventricular Tachycardia Overview

Supraventricular tachycardia is one type of heart rhythm disorder.

• Tachycardias are rhythm disorders in which the heart beats faster than normal.
  
  
• Supraventricular means "above the ventricles," in other words, originating from the atria, the upper chambers of the heart.
  
  
• Supraventricular tachycardia, then, is a rapid heartbeat originating in the atria.
  
  
• These are sometimes referred to as atrial tachycardias. However, the atrioventricular (AV) node may be involved directly or indirectly, so AV nodal tachycardias are also included in this category.

The heart consists of 4 chambers: 2 upper chambers called atria and 2 lower chambers called ventricles.

• The atria receive blood from blood vessels and contract to push blood into the ventricles.
  
  
• The ventricles then contract to push the blood out of the heart into the blood vessels of your lungs and the rest of your body.
  
  
• The heart usually beats 60-90 times a minute. A heart rate faster than 100 beats per minute is considered tachycardia.

Specialized heart cells coordinate the contractions by means of electrical signals.

• These specialized cells consist of the sinoatrial (SA) or sinus node in the right atrium and the AV node and the bundle of His in the wall between the right and left ventricles.
  
  
• The SA node, the natural pacemaker of the heart, starts the electrical signals and transmits them to the AV node.
  
  
• The AV node then activates the bundle of His and its branches, resulting in contraction of the ventricles.
  
  
• The atria and ventricles contract in quick sequence. Each sequence is 1 heartbeat.

Nerve impulses and the level of hormones in your blood influence the rate of heart contraction. A problem in any of these areas can cause abnormal heart rhythm (arrhythmia or dysrhythmia).

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 cannot contract strongly or fill with enough blood to satisfy the body's needs.
  
  
• Because of the ineffective contractions of the heart, the brain does not receive enough blood and oxygen. You can become light-headed, dizzy, or feel like fainting (syncope).

Supraventricular tachycardia can be found in healthy young children, in adolescents, and in people with underlying heart disease. Most people who experience it live a normal life without restrictions.

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