Supraventricular Tachycardia (SVT): What to Watch For and What to Do

SVT is a fast heart rhythm that starts above the heart’s ventricles. It can feel sudden and scary: heart racing, fluttering, lightheaded, or chest tightness. Some people have short bursts for seconds; others have episodes that last hours. Knowing simple steps and when to get help makes a big difference.

How to recognize SVT

Several clear signs point to SVT. You might notice a very fast heart rate (often 150–250 beats per minute), a pounding feeling in your chest or neck, dizziness, shortness of breath, sweating, or fainting. If the episode starts and stops suddenly, that’s a common SVT pattern. If you have severe chest pain, fainting, or trouble breathing, treat it like an emergency and call emergency services.

Tracking episodes helps your doctor. Note when they started, how long they lasted, what you were doing, and any triggers like caffeine or stress. If possible, capture an ECG or use a phone-based heart monitor so your clinician can see the rhythm during an episode.

Quick steps you can try right away

If you feel an SVT episode begin and you’re not fainting or in severe distress, try vagal maneuvers to slow your heart. The Valsalva maneuver (hold your breath and bear down like you’re having a bowel movement) is the simplest. Sip cold water or place a cold towel on your face to trigger the diving reflex. These moves increase vagal tone and can stop some SVTs.

Do NOT try carotid sinus massage without professional training—massaging the neck can cause serious problems, especially if you have carotid disease.

If vagal tricks don’t work and you’re stable, urgent treatment at a clinic or ER may include IV adenosine to reset the rhythm or medications such as beta-blockers or calcium-channel blockers. For ongoing or frequent SVT, many people meet with an electrophysiologist (heart rhythm specialist) to discuss longer-term options.

Catheter ablation is a common, minimally invasive procedure that targets the small circuit causing SVT. For typical AVNRT and AVRT types of SVT, ablation success rates are high—often above 90%—and many patients stop having episodes afterward. Your specialist will explain risks and recovery.

To reduce episodes, limit triggers: cut back on caffeine and energy drinks, avoid recreational stimulants, keep hydrated, manage stress, and treat thyroid disease or other medical problems. Regular follow-ups and a clear action plan for episodes give you control.

If you’re unsure whether symptoms are SVT, or you had a scary episode, see a doctor. Quick documentation, simple home tactics, and a plan with a cardiologist make living with—or curing—SVT much easier.