Supraventricular tachycardia (SVT) is a condition where the heart suddenly beats much faster than normal. It is an irregularly fast or erratic heartbeat that affects the hearts upper chambers. SVT happens when the electrical system that controls the heart rhythm is not working properly, causing the heart to suddenly beat much faster. The normal resting heart rate is 60 to 100 beats per minute (bpm), but with SVT, the heart rate suddenly goes above 100 bpm.

SVT falls into three main groups: atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reciprocating tachycardia (AVRT), and atrial tachycardia. Other types of SVT include Wolff-Parkinson-White syndrome and junctional tachycardia.

Symptoms of SVT include a sudden increase in heart rate, palpitations, chest discomfort, shortness of breath, lightheadedness, and fainting. Some people may not have any noticeable symptoms.

Causes of SVT include stress, caffeine, alcohol, cigarette smoke, and certain medications. Some people may not be aware of what brings on their symptoms.

Treatment for SVT depends on the severity of the symptoms and the underlying cause. For some people, lifestyle changes such as cutting down on caffeine or alcohol may be enough to reduce the frequency of episodes. Other treatment options include medications, electrical cardioversion, catheter ablation, and surgery.

It is important to see a doctor if you experience a fast heartbeat, especially if it lasts longer than a few minutes or is accompanied by other symptoms such as chest pain or shortness of breath.