Supraventricular Tachycardia

People with supraventricular tachycardia (SVT) often have an extra electrical circuit in their hearts and may occasionally experience very fast heart beats (arrhythmias) that are unrelated to exercise, fever or stress. When SVT occurs, the heart rate can reach up to 200 beats per minute or more.

Supraventricular Tachycardia Symptoms and Diagnosis

The most common symptoms of SVT include: 

  • Palpitations (racing heart sensation)
  • A pounding pulse
  • Feeling dizzy or lightheaded
  • Fainting (syncope)
  • Shortness of breath
  • Chest pain
  • Throat tightness
  • Sweating

Most likely, your doctor will diagnose SVT through a consultation and a physical exam. It is important to report any triggers of the fast heart rate, its duration, if it starts and stops suddenly, and if the beats are regular or irregular.

Diagnosis will include a resting electrocardiogram (EKG or ECG) and potential ECG monitoring over time to measure capture episodes of SVT.

Types of SVT
  • Atrioventricular nodal reentrant tachycardia (AVNRT)
  • Atrioventricular reciprocating tachycardia (AVRT), which includes Wolff-Parkinson-White syndrome
  • Atrial tachycardia

SVT can go away on its own, with medication, or with certain actions used to slow heart rate: holding your breath, coughing, or immersing your face in cold water.

SVT may last only briefly or for several hours. SVT may become a problem if it happens frequently, causes significant symptoms, or lasts an extended period of time.

Risk Factors

Although SVT episodes may occur in anyone, certain factors may increase an individual’s risk, such as:

  • Hyperthyroidism (overactive thyroid)
  • Family history of tachycardia
  • Structural abnormalities of the heart
  • Adverse reactions to certain medications such as antihistamines, theophylline, cough and cold medication, or appetite suppressants 

Supraventricular Tachycardia Treatment at BIDMC

You will likely receive treatment under the following circumstances:

  • You have symptoms such as dizziness, chest pain, or fainting
  • You experience SVT episodes that occur frequently or do not return to normal on their own

When episodes of SVT start suddenly and cause symptoms, you can try gagging, holding your breath, dipping your face in ice water, or coughing. These maneuvers stimulate the vagus nerve, one of the largest nerve systems in the body, which can slow the electrical impulses that control your heart rate.

If these maneuvers don’t work, your doctor may prescribe medication. However, if your heart rate is very elevated and you experience severe symptoms, you may need to seek medical attention. In some cases, an electrical cardioversion is used to reset the heart rhythm.

If you have recurring episodes of SVT, you may require medication such as beta-blockers, calcium channel blockers, or anti-arrhythmic medicines.

Patients who do not see improvement with medication, or experience side effects, may have the option of a catheter ablation procedure to correct the heart rhythm. 

Arrhythmia Services

The expert electrophysiologists in the CVI offer care and treatment for the full range of conditions that cause an abnormal heartbeat.

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