Symptomatic bradycardia is a slow heart rate, usually under 50 beats per minute, that causes poor blood flow to the brain or body. Common causes include heart block, heart attack, drugs such as beta blockers and high potassium.
Key symptoms
- Dizziness, lightheadedness or fainting
- Fatigue and weakness
- Shortness of breath
- Chest pain or pressure
- Confusion
What you find on exam
- Pulse below 50 and blood pressure
- Signs of shock: pale, cool skin and slow capillary refill
- Changes in mental status
- Lung crackles from heart failure
- Medication list: beta blockers, calcium channel blockers, digoxin
Tests
- 12-lead ECG: sinus bradycardia, second or third degree heart block
- Electrolytes, especially potassium
- Troponin for a possible heart attack
- Digoxin level and thyroid tests when relevant
Treatment basics
- Oxygen if saturation is low, IV access and monitor
- Atropine 1 mg IV, repeated every 3 to 5 minutes up to 3 mg
- Transcutaneous pacing if atropine does not work
- Epinephrine or dopamine infusion as a bridge
- Treat the cause: glucagon for beta blocker overdose, calcium for calcium channel blocker overdose or high potassium; transvenous pacing
Red flags
- Low blood pressure or shock
- Third degree heart block
- Fainting or chest pain
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Sources: NASEMSO National Model EMS Clinical Guidelines; NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations. Written by Making Synapses. Making Synapses is not affiliated with these organizations.