Supraventricular Tachycardia (SVT)

Causes of supraventricular tachycardia (SVT)

Supraventricular tachycardia is a broad term that describes a group of unusually fast heart rhythms that start in the ventricles of the atria or AV node.

A sustained heart rate over 100 beats a minute is called tachycardia. If you are experiencing tachycardia, your heart’s electrical impulses are not working correctly, and you feel like your heart is racing.

Most people with SVT do not need treatment. Others can control their heart rate with lifestyle changes, medication, cardioversion, or cardiac ablation.

Conditions or factors that may lead to supraventricular tachycardia include:

• Heart disease or heart failure.
• Smoking.
• Long-term lung disease.
• Consuming too much caffeine or alcohol.
• Thyroid conditions.
• Pregnancy.
• Certain medications such as decongestants, herbal diet medications, asthma medications.
• Recreational drug use, such as cocaine or meth.
• Surgery.

In some cases of SVT, there is not an apparent cause or trigger.

Risk factors of supraventricular tachycardia

Risk factors that increase your risk of experiencing supraventricular tachycardia include:

• Being female.
• Pregnancy.
• Older age.
• Coronary artery disease, previous heart surgery, or other heart conditions.
• Congenital heart disease.
• Anxiety, physical fatigue, or emotional stress.
• OTC and prescription drugs and supplements.
• Uncontrolled diabetes. Recreational drug use (cocaine or meth)
• Overactive or underactive thyroids.

Symptoms of supraventricular tachycardia

Symptoms of SVT vary from person to person. Some patients may not experience any signs or symptoms, while others may have symptoms that last for a few days.

Symptoms include:

• Rapid heartbeat.
• Feeling fluttering in your chest.
• Shortness of breath.
• Dizziness.
• Sweating.
• Pounding sensation in the neck.
• Fainting.

Children or infants may have a pulse rate greater than 200 beats per minute, have pale skin, or feed poorly.

Complications of supraventricular tachycardia (SVT)

In patients with coexisting heart conditions, untreated SVT can weaken the heart and lead to heart failure.

In exceedingly rare cases, SVT may cause cardiac arrest.

Diagnosing supraventricular tachycardia (SVT)

Your doctor can diagnose SVT through a physical exam, taking your medical history, and by reviewing the results of your diagnostic testing.

During the physical exam, your doctor will try to determine what is triggering your abnormally fast heart rate. If SVT is suspected, your doctor will perform an EKG to measure your heart’s electrical activity and record episodes.

You may need to wear a portable EKG to record episodes during your normal routine.

If necessary, your doctor may also order blood tests, a chest X-ray, an echocardiogram, a tilt table test, a stress test, or electrophysiological testing and mapping.

Treatment for supraventricular tachycardia (SVT)

If you are not experiencing symptoms of SVT, you may not need to be treated.

Medication is often the first-line therapy for patients who are experiencing symptoms.

Your doctor may also teach you ways to slow your heart rate using vagal maneuvers. Vagal maneuvers can help you slow your heart rate down through exercises such as holding your breath, straining, coughing, or submerging your face in the water.

In more severe cases, your doctor may perform a cardioversion or ablation procedure.

• Cardioversion. During a cardioversion procedure, a shock is delivered to your heart to restore your normal heart rhythm.
• Catheter ablation. Your doctor will use heat, extreme cold, or radiofrequency energy to ablate a section of your heart tissue to stop the abnormal electrical activity.

When to seek care

In most cases, SVT is not life-threatening. If your symptoms occur frequently and consistently, you should consult your doctor right away.

If you experience shortness of breath, weakness, dizziness, lightheadedness, or you faint, seek immediate medical attention.