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Paroxysmal supraventricular tachycardia (PSVT)

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Paroxysmal supraventricular tachycardia (PSVT)

Definition:

Paroxysmal supraventricular tachycardia (PSVT) is a rapid heart rate, which occurs from time to time (paroxysmal). PSVT starts with events taking place above the ventricles.

Alternative Names:
PSVT; Supraventricular tachycardia

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Causes, incidence, and risk factors:

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 the sinoatrial node (also called the sinus node or SA node).

The signal is conducted through the atria (the upper heart chambers) and stimulates the atria to contract. The electrical signal then passes through the atrioventricular node (AV node), and travels through the ventricles (the larger, lower chambers), stimulating them to contract.

Paroxysmal supraventricular tachycardia (PSVT) can be initiated in the SA node; in the atria or the atrial conduction pathways; or in the AV node. It occurs most often in young people and infants.

Risks include excessive smoking, caffeine, and alcohol use. PSVT can occur with digitalis toxicity. It can be a form of a re-entry tachycardia (an electrical current is caught in a reentrant loop, excessively stimulating the heart), as in the case of Wolff-Parkinson-White syndrome.

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