Sinus bradycardia
Normal P-QRS-T shape and regularity, just slow: rate under 60. Treat the patient, not the number. Only symptomatic bradycardia gets atropine or pacing.
How to identify Sinus bradycardia
- Rate
- Under 60
- Rhythm
- Regular
- P waves
- Upright, one before every QRS
- PR interval
- 0.12-0.20 s, constant
- QRS
- Under 0.12 s
- Clincher
- A normal sinus complex, just slow.
Rhythms it gets mistaken for
Sinus bradycardia vs Junctional escape rhythm
Sinus bradycardia has one upright P wave before every QRS, all the same shape. With a junctional escape rhythm you would see no upright P wave in front of the QRS. It starts in the SA node: a sinus rhythm.
Sinus bradycardia vs Normal sinus rhythm
Sinus bradycardia has a rate under 60/min. With normal sinus rhythm you would see a rate of 60-100/min.
Sinus bradycardia vs 1st-degree AV block
Sinus bradycardia has a normal PR interval of 0.12-0.20 s. With 1st-degree block you would see a PR interval over 0.20 s that is the same on every beat, with no dropped beats.
Treatment by certification level
Open your level. Treat the patient, not the strip.
Paramedic
Stable
Asymptomatic: watch it, do not treat the number.
- Monitor, IV access, transport and reassess.
- No atropine, pacing or infusion for the asymptomatic patient.
- If it becomes symptomatic (hypotension, altered mental status, signs of shock, ischemic chest pain, acute heart failure): atropine 1 mg every 3-5 minutes (maximum 3 mg), then transcutaneous pacing, or dopamine 5-20 mcg/kg/min or epinephrine 2-10 mcg/min.
Unstable
Symptomatic bradycardia: atropine, then pacing or an infusion.
- Oxygenation and ventilation support, IV access, monitor.
- Atropine 1 mg IV every 3-5 minutes, maximum 3 mg.
- No response: transcutaneous pacing (rate 60-80, mA up until capture, then slightly above). Confirm mechanical capture with a femoral pulse. Sedation and analgesia.
- Or a chronotropic infusion: dopamine 5-20 mcg/kg/min, or epinephrine 2-10 mcg/min, titrated to effect.
- Look for and treat the cause: hypoxia first, then medications and high potassium.
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
Symptomatic bradycardia with a pulse.
- Support oxygenation and ventilation, establish IV access, and move the patient.
- 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.