Paroxysmal supraventricular tachycardia

Alternative names:

PSVT

Definition:

A rapid heart rate, initiated above the ventricles, that occurs sporadically (paroxysmal).

Causes, incidence, and risk factors:

Normally, the chambers of the heart (atria and ventricles) contract in a coordinated manner. The signal to contract begins in the sinoatrial node (sinus node, SA node). It is conducted through the atria (the upper heart chambers) and stimulates them to contract. It passes through the atrioventricular node (AV node), then travels through the ventricles (the larger, lower chambers) and stimulates 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 who have normal hearts. Risks include excessive smoking, caffeine, and alcohol use. PSVT can occur with digitalis toxicity. It can be a form of a re-entry tachycardia, resembling Wolff-Parkinson-White syndrome.