Supraventricular Tachycardia

Treatment of Supraventricular Tachycardia (SVT)

An episode of Supraventricular Tachycardia most often will terminate spontaneously. When an episode lasts for several minutes to hours, occasionally a person may be able to terminate the episode using a variety of “vagal” maneuvers such as breath holding while bearing down or dunking your face in cold water. However, when an episode does not resolve, occasionally the paramedics or emergency room physicians are required to deliver an intravenous drug (known as adenosine) to terminate the episode.

Once the acute episode is terminated, treatment may be necessary to prevent the recurrent episodes. If episodes are exceedingly rare and do not impact a person’s life, it may be reasonable to do nothing besides observation. However, in a person who has frequent recurrences or whose day-to-day function is limited by the occurrence or fear of occurrence of SVT, it is reasonable to seek treatment.

Medical therapy

Depending on the type of SVT, a variety of medications may be appropriate. Such medications may include beta-blockers, calcium-channel blockers, or anti-arrhythmic medications such as flecainide, propafenone, sotalol, or dofetilide. However, in general, it is usually not warranted to treat with one of these medications because they all have possible side effects and most SVT can be successfully cured with a straightforward catheter ablation procedure.

Catheter Ablation for SVT

Catheter ablation for SVT utilizing radiofrequency ablation (electrocautery injury) was developed in the 1980’s and has since revolutionized the treatment of SVT. With catheter ablation, a procedure is performed entirely through intravenous catheters inserted into the veins in the leg and sometime the shoulder. It is a minimally invasive procedure. That is, no open heart surgery is needed. Generally, procedures can be performed on an outpatient basis. Overall cure rates with catheter ablation is >90% and can be as high as 96-98% depending on the specific type of SVT.

During a catheter ablation procedure, catheters (long wire electrodes) are advanced through the veins in the leg up to the heart.

Various measurements of the electrical system are performed. If a person is in normal rhythm at the time of the procedure, an attempt is made then to reproduce the SVT by pacing the heart through the catheters. Occasionally an intravenous medicine called isoproterenol is required to “rev up” the heart in order to reproduce the SVT. Once the SVT is reproduced, the specific type of SVT can be diagnosed using the catheters in the heart.

Once the SVT is diagnosed, to cure the SVT, an ablation catheter is advanced to the heart. An ablation catheter is capable of delivering small radiofrequency lesions (electrocautery burns) on the order of 4-5 mm in diameter. These radiofrequency lesions have no long-term adverse consequences. Depending on the type of SVT, these radiofrequency lesions are delivered in various locations of the heart.

Balloon Catheter

Occasionally, more complex diagnostic and ablation techniques are required for catheter ablation of SVT. This may be the case particularly in patients with other heart problems or a history of heart surgery.

In such situations, sophisticated 3-dimensional mapping techniques using a balloon catheter may be used to identify the location necessary to successful ablate the SVT.

Learn more about supraventricular tachycardia (SVT)

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