PATIENT EDUCATION · THE SIMPLE EXPLANATION

Supraventricular tachycardia (SVT), made clear.

A few pictures. Short explanations. Start here, then explore the full guide when you’re ready.

01 · SUPRAVENTRICULAR TACHYCARDIA (SVT)

What is SVT?

First, how does a normal heartbeat work?

Normal heart conduction showing the SA node, AV node, bundle branches, and pathways into the ventricles. — **Follow one normal heartbeat:** The signal starts in the SA node, spreads through the atria, pauses briefly at the AV node, then travels through the heart’s electrical pathways to the ventricles. The upper chambers squeeze first; the lower chambers follow in a coordinated heartbeat.

SVT is a fast rhythm involving the upper chambers or the electrical connections above the ventricles. Episodes often start and stop suddenly.

There are 3 main types of SVT: AVNRT, AVRT, and focal atrial tachycardia. The pictures below show how each type differs from a normal heartbeat.

1. AVNRT: a loop near the AV node

Magnified AV nodal region showing typical AVNRT: orange arrows travel down the slow pathway, blue arrows return up the fast pathway, and a separate downward signal travels toward the ventricles.

This picture shows AVNRT: a repeating loop using slow and fast pathways near the AV node.

2. AVRT: an extra electrical connection

Labeled cutaway heart showing orthodromic AVRT with downward normal AV conduction, ventricular activation, and upward return through a left lateral accessory pathway at the mitral valve junction.

AVRT uses an extra connection between an upper and lower chamber, allowing the electrical signal to travel in a repeating loop.

3. Focal atrial tachycardia: a small area firing rapidly

Labeled cutaway heart showing an extra electrical focus in the right atrium, separate from the SA node, with signals spreading across the atria and through the AV node to the ventricles.

Focal atrial tachycardia comes from a small area sending rapid signals in an atrium. An EKG helps identify the rhythm.

These common SVTs do not usually carry the same stroke risk as AFib.

03 · SUPRAVENTRICULAR TACHYCARDIA (SVT)

How does ablation help?

Magnified AV nodal region showing a blue catheter tip treating the orange slow pathway, separate from the labeled AV node and blue fast pathway. The blue catheter shaft is labeled Ablation catheter.

A catheter is guided through blood vessels to the heart. Treatment targets the extra pathway or small area keeping the rhythm going. For common SVTs, ablation can provide a lasting cure, although recurrence is possible.

This example treats the slow pathway in AVNRT. Your treatment target depends on the type of SVT.

Sources & further readingAHA: Fast heart rate and SVT ACC/AHA/HRS guideline: SVT management ACC CardioSmart: Living with SVT ACC CardioSmart: Questions to ask

Updated October 2026. Educational information; your own care plan may differ.

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