How do I tell SVT from sinus tachycardia?

Sinus tach has a visible upright P wave before every QRS and speeds up gradually with a cause (pain, fever, volume). SVT usually has hidden or retrograde P waves and an abrupt onset. Rate overlaps, so morphology and onset are what distinguish them.

It depends on the patient. A stable patient may tolerate SVT while the team tries vagal maneuvers or adenosine; an unstable patient may need cardioversion. RN PocketPal doesn't make that call — stability and the clinician do.

What if the QRS is wide?

A wide-complex regular tachycardia should be treated as ventricular tachycardia until proven otherwise. Don't assume SVT with aberrancy — escalate.

Supraventricular tachycardia (SVT) — an educational nurse reference.

The narrow-complex regular tachycardia with a sudden onset — and how it differs from a ramping sinus tach.

Recognizing this rhythm at the bedside means matching pattern, intervals, and clinical context. This page covers the educational pattern; calipers and your clinical judgment carry it across the line.

What RN PocketPal does

Identifying traits

Rate: typically 150–250 bpm.
Rhythm: regular.
P waves: often hidden in the preceding T wave, or retrograde (inverted after the QRS).
QRS: narrow (< 0.12 sec) unless aberrant conduction.
Onset/offset: abrupt (paroxysmal) — it starts and stops suddenly.

Verify with

Onset pattern: SVT snaps on; sinus tach ramps up and down with the patient's physiology.
Look for absent or retrograde P waves rather than an upright P before every QRS.
Patient stability + the clinical team for vagal maneuvers, adenosine, or cardioversion decisions.

Who it’s for

For Nurses and nursing students learning rhythm interpretation.

We publish a real ten-second recording on a rhythm reference only where we hold one under an open licence, rather than illustrating the pattern with a drawing. This rhythm does not have one yet — the identifying traits above are the reference until it does.

Rhythms this gets confused with

Known-answer practice — RN PocketPal does not interpret your patient's monitor. To work through strips with the answer revealed after you commit, open Rhythm Practice.

Frequently asked questions

How do I tell SVT from sinus tachycardia?: Sinus tach has a visible upright P wave before every QRS and speeds up gradually with a cause (pain, fever, volume). SVT usually has hidden or retrograde P waves and an abrupt onset. Rate overlaps, so morphology and onset are what distinguish them.
Is SVT an emergency?: It depends on the patient. A stable patient may tolerate SVT while the team tries vagal maneuvers or adenosine; an unstable patient may need cardioversion. RN PocketPal doesn't make that call — stability and the clinician do.
What if the QRS is wide?: A wide-complex regular tachycardia should be treated as ventricular tachycardia until proven otherwise. Don't assume SVT with aberrancy — escalate.

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Reviewed by RN PocketPal's founding RN. Last reviewed June 5, 2026.