Sinus tachycardia
Normal P-QRS-T shape and regularity, just fast: rate over 100. It is almost always a response to something (pain, fever, hypovolemia, hypoxia, anxiety). Find and treat that cause rather than the rate.
How to identify Sinus tachycardia
- Rate
- Over 100
- Rhythm
- Regular
- P waves
- Upright, one before every QRS (can crowd into the T wave at speed)
- PR interval
- 0.12-0.20 s, constant
- QRS
- Under 0.12 s
- Clincher
- A normal sinus complex, just fast.
- Common causes
- Almost always secondary: pain, fever, hypovolemia, hypoxia, anxiety.
Rhythms it gets mistaken for
Sinus tachycardia vs Supraventricular tachycardia
Sinus tachycardia has one upright P wave before every QRS, all the same shape. With SVT you would see no P wave you can see at all. It starts in the SA node: a sinus rhythm.
Sinus tachycardia vs Junctional tachycardia
Sinus tachycardia has one upright P wave before every QRS, all the same shape. With junctional tachycardia you would see an inverted P wave just before or just after each QRS. It starts in the SA node: a sinus rhythm.
Sinus tachycardia vs Atrial flutter (2:1)
Sinus tachycardia has one upright P wave before every QRS, all the same shape. With atrial flutter at 2:1 you would see sawtooth flutter waves instead of P waves. It starts in the SA node: a sinus rhythm.
Treatment by certification level
Open your level. Treat the patient, not the strip.
Paramedic
Stable
Treat the cause, not the rate.
- Find what is driving it: pain, fever, hypovolemia, hypoxia, anxiety.
- Treat that cause. A fast rate compensating for something else is the patient's own fix, so it is not slowed.
Unstable
Treat the cause, not the rate.
- Find what is driving it: pain, fever, hypovolemia, hypoxia, anxiety.
- Treat that cause. A fast rate compensating for something else is the patient's own fix, so it is not slowed.
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.