Supraventricular tachycardia (SVT) is condition in which the heart will beat very fast for reasons not related to stress, illness or exercise. The condition is divided into two types, atrioventricular reciprocating tachycardia and atrioventricular nodal reentrant tachycardia. Episodes of SVT are linked to a malfunction in the electrical system of the heart, which can cause it to beat between 100 and 300 times per minute. The cause of the malfunction is not known.
Causes of SVT Tachycardia
Aside from the electrical problem, SVT can be brought on by the use of medications such as theophylline, which treats lung problems, or digoxin, which is used for heart issues. The condition may be inherited, as in Wolff-Parkinson-White syndrome. Lung illnesses such as pneumonia and COPD can also be at the root of SVT.
Symptoms of SVT
While SVT can occur without any symptoms, it most often manifests as dizziness, a rapid pulse and palpitations. Other symptoms that may present are tightness in the throat, sweating, chest pain, shortness of breath and fainting.
A doctor can determine if someone has SVT through a physical exam and the answers given to medical questions, as well as running certain tests. It is most important to determine if there is a particular trigger to an episode and how regularly the heart beats while it is occuring. The patient may also need to undergo an EKG, either in the office or with a portable monitor. In some cases, an X-ray of the chest or blood tests may necessary in the search for a cause.
While many cases of SVT do not cause symptoms, others may require treatment. This can be accomplished through medication or performing a vagal maneuver such as gagging, placing the face in ice water, coughing or bearing down as though having a bowel movement. These maneuvers all help to reduce the heart rate. Medications such as verapamil or adenosine can be taken when SVT begins. In extreme cases, the heart rate may need to be reset electrically or a small part of the heart destroyed to eliminate the problem.
Avoiding caffeine, alcohol, smoking and medications such as diet pills, decongestants, herbs and energy boosters can reduce or eliminate SVT. The patient should also avoid illegal drugs like meth and cocaine. Keeping a trigger diary can helpful in SVT prevention.