Supraventricular tachycardia

Supraventricular tachycardia, often shortened to SVT, is an umbrella term for a group of abnormally fast heart rhythms that originate above the heart's ventricles, in the atria or the atrioventricular node. During an episode the heart commonly beats between 150 and 220 times per minute, well above the normal resting range of 60 to 100 beats per minute, producing symptoms such as palpitations, shortness of breath, chest discomfort, dizziness, sweating, and in some cases fainting. The abnormal rhythm is usually driven by one of two mechanisms: an electrical signal that repeatedly loops through a short circuit in the heart's conduction system, called re-entry, or heart muscle cells that fire faster than they should on their own. A well-known example is Wolff-Parkinson-White syndrome, in which an extra electrical pathway between the atria and ventricles allows signals to re-enter and sustain a rapid rhythm. Other recognized types include atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. The condition affects roughly three percent of the general population at some point, and treatment ranges from simple maneuvers that stimulate the vagus nerve to medications, electrical cardioversion, or catheter ablation for recurring cases.