Paroxysmal supraventricular tachycardia (PSVT) is an occasional rapid heart rate. "Paroxysmal" means from time to time.

Normally, the chambers of the heart (atria and ventricles) contract in a coordinated manner. The contractions are caused by an electrical signal that begins in an area of the heart called the sinoatrial node (also called the sinus node or SA node). The signal moves through the upper heart chambers (the atria) and tells the atria to contract.

PSVT starts with events taking place above the lower heart chambers (ventricles). PSVT can be initiated in the SA node, in the upper heart chambers (atria), in the atrial conduction pathways, or other areas.

PSVT can occur with digitalis toxicity and conditions such as Wolff-Parkinson-White syndrome.

The condition occurs most often in young people and infants.

The following increase your risk for PSVT:

• Alcohol use
• Caffeine use
• Illicit drug use
• Smoking