Topic Overview
Supraventricular tachycardia (SVT) is a fast heart rate that begins in the upper chambers of the heart (atria). With SVT, abnormal electrical connections in the heart cause it to beat too fast.
There are many types of SVT. Each type causes the abnormal fast heart rate in a slightly different way.
Treatment depends on the type of SVT and what is causing it, if known. Treatment might include medicines that slow the heart rate or a procedure called catheter ablation that stops the rhythm problem.
Atrial fibrillation and atrial flutter
Atrial fibrillation is a common heart rhythm problem. The heart's upper chambers (atria) beat irregularly. But it is not commonly considered a type of SVT.
Atrial flutter is like atrial fibrillation, because the electrical problem is in the atria. But with atrial flutter, the heart beats very fast in a regular rhythm.
Atrioventricular nodal reentrant tachycardia
Atrioventricular nodal reentrant
tachycardia (AVNRT) is a common type of
supraventricular tachycardia. It accounts for many of
the fast heart rates that start in the upper part of the heart (excluding
atrial fibrillation). Atrioventricular (AV) nodal reentrant tachycardia can
cause symptoms at any age. It typically is not
a result of other forms of heart disease.
AVNRT is caused by an abnormal or extra
electrical pathway in the heart, a kind of "short circuit." Electrical pathways
in the heart consist of microscopic muscle fibers that conduct electrical
impulses. Normally, a single electrical pathway allows impulses to travel from
the upper to the lower chambers. An extra electrical pathway in the AV node allows those
impulses to travel backward at the same time, starting another heartbeat.
During AVNRT the electrical impulses continuously go
around the two pathways. This is known as "reentry" and can lead to a very fast
heart rate.
Atrioventricular reciprocating tachycardia
Atrioventricular reciprocating tachycardia (AVRT) occurs when there
is an extra electrical pathway linking the upper (atria) and lower (ventricles)
chambers of the heart.
AVRT includes Wolff-Parkinson-White (WPW) syndrome.
Normally, the
AV node is the only tissue that conducts electrical
impulses between the upper and lower chambers of the heart. All electrical
impulses must go through the AV node to reach the lower chambers of the heart.
In an atrioventricular reciprocating tachycardia, electrical impulses travel
one direction in the normal manner, down the AV node to the lower chambers
(ventricles), but they then travel back up to the upper chambers (atria)
through an abnormal, extra electrical pathway (accessory pathway) located
outside the AV node.
Symptoms may start
during the teen or young adult years.
Atrial tachycardia
Atrial tachycardia is a type of
fast heart rate caused by rapid electrical signals that begin in the upper
chambers of the heart. As a result, the heart can sometimes beat very
rapidly.
Multifocal atrial tachycardia
Multifocal atrial
tachycardia is an abnormal, rapid rhythm that occurs most commonly in older people who have COPD (chronic obstructive pulmonary disease) and heart failure.
During this
rhythm, three or more different areas of the atrium initiate extra heartbeats.
It is somewhat similar to having several different kinds of premature atrial
contractions (PACs) occurring in the same person. These different areas of
electrical activity can be seen on an
electrocardiogram (EKG, ECG) and are used as the
criteria for diagnosing this arrhythmia.
On EKG, multifocal atrial tachycardia
may appear similar to atrial fibrillation. But it is a distinct condition. The
problem with this rhythm is that it causes a persistently fast heart rate that
may be difficult to control. If a lung disease is causing this rhythm problem, treating the lung disease might also control the rhythm problem.
Junctional tachycardia
Junctional tachycardia is a
rare fast heart rate that starts in the area between the upper and lower
chambers of the heart. This rhythm may happen in children who have had heart surgery.
Sinus tachycardia
Normal sinus tachycardia. Sinus tachycardia is present when
a person's heart rate is over 100 beats per minute. This is normal if there is a clear reason
for the fast heart rate, such as exercise, pain, or fever. With sinus tachycardia, the electrical system
of the heart is working normally.
Abnormal (inappropriate) sinus
tachycardia. Sinus tachycardia (heart rate over 100 beats per minute) is not normal if there is
no apparent cause. In this rare condition, the electrical system of the
heart is working normally.
People with inappropriate sinus
tachycardia typically don't have any heart disease. Inappropriate sinus
tachycardia with no diagnosed heart problem may mean your
autonomic nervous system isn't working right.
Sinus node reentrant tachycardia
Sinus node
reentrant tachycardia is a rare type of fast heart rate. This type is caused by
abnormal conduction of electrical impulses within the
sinus node.
Sinus node reentrant
tachycardia begins and ends very suddenly.