Supraventricular tachycardia is a rapid heart rate (tachycardia, or a heart rate above 100 beats per minute) that is caused by electrical impulses that originate above the heart's ventricles. Many physicians include all of the many tachycardias that involve the atrioventricular node (AV node) under this classification, but others do not. Supraventricular tachycardia does not include those tachycardia rhythms that originate from the ventricles (ventricular tachycardias) such as ventricular tachycardia or ventricular fibrillation. Supraventricular tachycardia is also called paroxysmal supraventricular tachycardia and abbreviated either SVT or PSVT.
The following is a brief description of the heart's normal electrical activity. This is presented so that the abnormal electrical activity can be better understood:
The following is a brief description of the heart's normal electrical activity. This is presented so that the abnormal electrical activity can be better understood:
- The heart consists of four chambers; two upper chambers called atria and two lower chambers called ventricles.
- The atria receive blood from blood vessels and, with coordinated electrical impulses from the sinoatrial (SA) node, contract to push blood into the ventricles.
- The ventricles then contract to push the blood out of the heart into the blood vessels of the lungs and to the rest of the body.
- The heart usually beats 60-90 times a minute. A heart rate faster than 100 beats per minute is considered tachycardia.
