Two common types of supraventricular tachycardia-atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT)-are caused by an abnormal electrical pathway in the heart and often occur in people who do not have any other type of heart disease. What causes this abnormal pathway is not clear.

Some experts believe that AVRT-specifically Wolff-Parkinson-White syndrome-may in some cases be inherited.

Other types of supraventricular tachycardia may be caused by:

• Atrial cells firing off signals rapidly (called atrial tachycardia). Atrial tachycardia is seen most often in people with structural heart disease.
• Overly high levels of the heart medicine digoxin (such as Lanoxicaps or Lanoxin) or the bronchodilator theophylline (such as Bronkodyl, Elixophyllin, Slo-Bid, Slo-Phyllin, or Theo-Dur).
• Other serious health problems, such as chronic obstructive pulmonary disease, heart failure, pneumonia, or metabolic problems.