Supraventricular Tachycardia (SVT): Understanding the Condition

Introduction

Supraventricular tachycardia (SVT) is a condition in which the heart suddenly beats very fast due to improper electrical signals originating above the ventricles (the lower chambers of the heart). It is a broad term that includes various types of arrhythmias affecting the atria (upper heart chambers) or the atrioventricular (AV) node.

Causes of SVT

SVT occurs when abnormal electrical pathways in the heart lead to rapid heartbeats. Common causes include: - Re-entry circuits : Additional electrical pathways that create a loop of rapid signals (as seen in AV nodal reentrant tachycardia - AVNRT). - Accessory pathways : Extra electrical pathways between the atria and ventricles (as in Wolff-Parkinson-White syndrome). - Triggered activity : Abnormal impulse generation due to factors like stress, caffeine, or certain heart conditions.

Symptoms of SVT

A person with SVT may experience: - A very rapid heart rate (often over 150-250 beats per minute) - Palpitations (fast or irregular heartbeat sensation) - Dizziness or lightheadedness - Shortness of breath - Chest discomfort or mild pain - Anxiety - Fatigue after an episode

Diagnosing SVT

SVT is typically diagnosed using: - Electrocardiogram (ECG) : Records heart's electrical activity. - Holter monitor or event recorder : Monitors heart rhythm over time. - Electrophysiologic study (EPS) : Determines the exact abnormal circuitry causing SVT.

Treatment Options for SVT

SVT is usually not life-threatening, but treatment may be needed if episodes are prolonged or frequent. Common treatments include:

Acute Management

• Vagal maneuvers : Techniques like bearing down, coughing, or placing an ice pack on the face to slow the heart rate.
• Medications : Intravenous adenosine is often used to stop SVT.

• Cardioversion : A controlled electric shock to restore normal rhythm in severe cases.

  Long-term Management

• Beta-blockers or calcium channel blockers : Used to prevent recurrent episodes.

• Catheter ablation : A minimally invasive procedure to destroy the abnormal pathway causing SVT.
• Lifestyle modifications : Reducing stress, avoiding caffeine and alcohol, and ensuring good hydration.

Key Takeaways

• SVT is a fast heart rhythm originating above the ventricles.
• It can be triggered by structural heart abnormalities, stress, or stimulants.
• Diagnosis is straightforward with ECG and sometimes additional monitoring.
• Treatment includes emergency management and preventive measures like medication or catheter ablation.

When to Seek Medical Help

Seek immediate medical attention if you experience prolonged palpitations, chest pain, severe dizziness, or fainting.

Source recommendations

1. 2023 European Society of Cardiology (ESC) Guidelines on Cardiac Arrhythmias

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
2. https://pubmed.ncbi.nlm.nih.gov/36017572/
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
4. https://academic.oup.com/eurheartj/article-abstract/43/40/3997/6675633
5. https://www.heartrhythmjournal.com/article/S1547-5271(23)02246-4/fulltext

2. 2020 American Heart Association (AHA) Guidelines for the Diagnosis and Management of Supraventricular Tachycardia

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
2. https://pubmed.ncbi.nlm.nih.gov/38033089/
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000937
4. https://pubmed.ncbi.nlm.nih.gov/33215931/
5. https://www.escardio.org/static-file/Escardio/Guidelines/Documents/ehaa612.pdf