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.

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.

Download RN PocketPal

Download on theApp Store Get it onGoogle Play

Want early-access updates?

RN PocketPal is live on the App Store and Google Play. Join the list for beta builds and upcoming tools.

RoleSpecialtyBiggest pain right nowLaunch platformEmail address

By joining, you agree to our privacy policy and terms. We email occasional updates — unsubscribe anytime.

Reviewed by RN PocketPal Clinical Team, RN. Last reviewed June 4, 2026.