Supraventricular tachycardia

Supraventricular tachycardia is a form of tachycardia that originates above the atrioventricular node of the heart. Although serious, it is far less dangerous than ventricular tachycardia. It can originate in several parts of the heart and generally also brings symptoms such as a pounding heart, shortness of breath, chest pain, dizziness and, in severe cases, loss of consciousness. 
It can usually be distinguished from ventricular tachycardia by the fact that the QRS portion of the sinus rhythm on an electrocardiogram is also compressed.
Supraventricular tachycardia is unpleasant, but not life threatening. As such, supportive care is required until the heart rate returns to normal.
Supraventricular tachycardia at Wikipedia
Category:Symptoms