SVT stands for Supraventricular Tachycardia, a condition in which the heart suddenly beats much faster than normal due to abnormal electrical signals originating in the upper chambers of the heart (the atria) or around the atrioventricular (AV) node.
Typical Features
- Heart rate often 150–250 beats per minute
- Sudden onset and sudden stopping of episodes
- Palpitations (feeling the heart racing or pounding)
- Dizziness or lightheadedness
- Shortness of breath
- Chest discomfort
- Anxiety or a feeling of unease
- Occasionally fainting (syncope)
Common Types of SVT
- Atrioventricular Nodal Reentrant Tachycardia – the most common type.
- Atrioventricular Reentrant Tachycardia – often associated with an extra electrical pathway.
- Atrial Tachycardia – originates from a small area within the atrium.
Causes and Triggers
SVT may occur without a clear cause, but triggers can include:
- Stress or anxiety
- Excess caffeine or energy drinks
- Alcohol
- Smoking
- Certain medications
- Overactive thyroid
- Heart disease in some cases
Diagnosis
Doctors typically diagnose SVT using:
- Electrocardiogram (ECG/EKG)
- Holter monitor or event monitor
- Blood tests
- Sometimes an electrophysiology study
Treatment
Treatment depends on severity and frequency:
- Vagal maneuvers (specific techniques that stimulate the vagus nerve and may slow the heart rate)
- Medications such as adenosine, beta-blockers, or calcium channel blockers
- Electrical cardioversion in urgent situations
- Catheter ablation, which can permanently cure many forms of SVT
Is SVT Dangerous?
Most SVTs are not life-threatening, especially in otherwise healthy people, but recurrent episodes can affect quality of life and occasionally cause complications. Any episode associated with chest pain, severe shortness of breath, fainting, or prolonged rapid heart rate should be evaluated promptly by a healthcare professional.