Supraventricular tachycardia
Also called SVT.
Narrow QRS, very fast (about 150-220) and metronome-regular, with P waves buried and not visible. The narrow QRS is what separates it from V-tach.
How to identify Supraventricular tachycardia
- Rate
- About 150-220
- Rhythm
- Regular, metronome-steady
- P waves
- Not visible, buried
- PR interval
- Not measurable
- QRS
- Under 0.12 s
- Clincher
- Narrow, very fast and regular. The narrow QRS is what separates it from V-tach.
Rhythms it gets mistaken for
Supraventricular tachycardia vs Junctional tachycardia
Supraventricular tachycardia has no P wave you can see at all. With junctional tachycardia you would see an inverted P wave just before or just after each QRS. It starts above the ventricles.
Supraventricular tachycardia vs Sinus tachycardia
Supraventricular tachycardia has no P wave you can see at all. With sinus tachycardia you would see one upright P wave before every QRS, all the same shape. It starts above the ventricles.
Supraventricular tachycardia vs Atrial flutter (2:1)
Supraventricular tachycardia has no P wave you can see at all. With atrial flutter at 2:1 you would see sawtooth flutter waves instead of P waves.
Treatment by certification level
Open your level. Treat the patient, not the strip.
Paramedic
Stable
Stable SVT: vagal maneuver, then adenosine.
- Oxygen as needed, IV access, monitoring.
- Vagal maneuver: Valsalva first. No carotid massage with a bruit, carotid disease, or prior stroke or TIA.
- Adenosine 6 mg rapid IV push with an immediate 20 mL flush, arm raised. Then 12 mg if needed.
- Warn the patient: flushing, chest pressure and a brief pause on the monitor are expected.
Unstable
Unstable SVT: synchronized cardioversion.
- Sedate the conscious patient if time and blood pressure allow.
- Synchronized cardioversion starting at 50-100 J; escalate if it fails.
- If the rhythm is regular, adenosine 6 mg rapid IV push may be tried while you set up, but only if it causes no delay. Cardioversion never waits on it.
AEMT
Stable
Pulse present and stable.
- Oxygen only if hypoxic or short of breath, IV access, monitoring.
- Acquire and transmit a 12-lead ECG. Interpreting it is a Paramedic skill.
- Transport and reassess. Request a paramedic if the patient worsens.
Unstable
Unstable with a pulse.
- Oxygen if hypoxic, IV access, close monitoring.
- Expedited transport, with a paramedic intercept if that is genuinely faster than reaching the hospital.
Synchronized cardioversion and pacing are Paramedic-only, so the AEMT has no electrical option for a patient with a pulse. Never put the AED on this patient.
EMT
Stable
Pulse present: assess and support.
- Treat the patient, not the rhythm name: airway, breathing, circulation, vital signs.
- Oxygen if the SpO2 is under 94%, the patient is short of breath, or shows signs of shock.
- Request ALS and transport promptly. Reassess on the way.
An AED goes only on a patient who is unresponsive, not breathing and pulseless. It cannot feel a pulse, so on a patient with a pulse it can advise a shock that would do harm.
Unstable
Pulse present but poorly perfusing: this patient needs ALS fast.
- Treat the patient, not the rhythm name: airway, breathing, circulation, vital signs.
- Oxygen if the SpO2 is under 94%, the patient is short of breath, or shows signs of shock.
- Request ALS and transport promptly. Reassess on the way.
An AED goes only on a patient who is unresponsive, not breathing and pulseless. It cannot feel a pulse, so on a patient with a pulse it can advise a shock that would do harm.