Supraventricular Tachycardia

Types of supraventricular tachycardia

SVT isn’t just one condition. It's a group of related heart rhythm problems that all start above the ventricles. Doctors classify its various types based on how electrical signals travel from the upper chamber (atria) to the ventricles.

Here are the most common types:

• Atrioventricular nodal reentrant tachycardia (AVNRT): The most common type, AVNRT happens when a looping electrical signal gets stuck in a circuit near the heart’s AV node (the heart’s electrical relay station between the atria and ventricles).
• Atrioventricular reciprocating tachycardia (AVRT): This type involves an extra electrical pathway between the upper and lower chambers of the heart.
• Atrial tachycardia: This form starts in the atria (the heart’s upper chambers), where one area fires off electrical signals faster than normal, leading to a rapid heartbeat.

Risk factors for supraventricular tachycardia

Supraventricular tachycardia (SVT) affects people of all ages, but certain traits, health conditions and lifestyle habits can increase your chances of developing SVT or having an SVT episode. These factors may affect the heart’s structure or its electrical system over time.

Risk factors for SVT include:

• Age: Although SVT can occur in children and young adults, the condition is more common in people over age 65.
• Anemia: Anemia (low red blood cell count) can cause or worsen a rapid heart rate.
• Electrolyte imbalances: Low levels of potassium, magnesium or calcium can affect the heart’s ability to maintain a steady rhythm.
• Family history: Having a family history of SVT increases your risk of developing it.
• Heart disease: Conditions such as high blood pressure, congenital heart disease, and coronary artery disease can increase your risk of SVT.
• Heart surgery: Having a previous heart surgery can predispose you to SVT.
• High levels of stress: Emotional stress can affect your heart’s electrical system and may trigger SVT episodes.
• Sex: SVT occurs more often in women than men.
• Stimulant use: Caffeine, tobacco and some illicit drugs can trigger rapid heart rhythms in some people.
• Thyroid issues: An overactive thyroid (hyperthyroidism) can increase the risk of SVT by speeding up your heart rate.

Complications of SVT

Although many people find that SVT is manageable, it's important to remember that the condition can lead to significant health concerns if left unchecked. Understanding these complications not only empowers you to make informed decisions about your care but also highlights the importance of regular monitoring and communication with your healthcare team.

Here are some key SVT complications to keep in mind:

• Heart failure: Prolonged rapid heart rates can weaken the heart muscle over time.
• Sudden cardiac arrest: Some types of SVT can lead to severe increases in your heart rate that can cause your heart to stop working suddenly.

Diagnosing supraventricular tachycardia

Supraventricular tachycardia (SVT) can sometimes be tricky to diagnose, especially if episodes are brief or happen infrequently. Getting an accurate diagnosis is the first step toward finding answers and feeling better. Your care team will gather details about your symptoms, review your medical history and use a few simple tests to get a clearer picture of what’s going on.

Supraventricular tachycardia treatment

You may not need treatment for SVT, but your doctor may want to slow your heart rate, prevent future episodes or address any underlying causes. Your care plan will depend on the type of SVT you have, how often symptoms occur and your overall health. A cardiologist may recommend lifestyle changes, medications or procedures to help you feel better and stay active.

If your rapid heart rate is considered a medical emergency, you may need cardioversion, a procedure to deliver an electrical shock to your heart and restore its natural rhythm.

Frequently asked questions