You do not need to be a cardiologist. You need to spot what is normal, what is dangerous, and what to do next.
Normal sinus rhythm
- Rate 60 to 100
- Regular
- A P wave before every QRS
- PR interval 0.12 to 0.20 seconds
- QRS under 0.12 seconds
Rhythms to know
| Rhythm | What it looks like | What to do |
|---|---|---|
| Sinus bradycardia | Normal pattern, rate under 60 | Treat only if symptomatic: atropine 1 mg IV, then pacing or drips |
| Sinus tachycardia | Normal pattern, rate over 100 | Find and treat the cause: pain, fever, bleeding, dehydration |
| Atrial fibrillation | No P waves, irregularly irregular | Rate control and blood thinners (stroke risk) |
| Atrial flutter | Sawtooth flutter waves | Rate control, blood thinners, sometimes cardioversion |
| SVT | Narrow, regular, very fast (often 150 to 220) | Vagal maneuvers, then adenosine |
| Ventricular tachycardia | Wide, regular, fast | Check for a pulse. No pulse: CPR and defibrillation. Pulse but unstable: synchronized cardioversion |
| Ventricular fibrillation | Chaotic squiggle, no real beats | CPR and defibrillate right away |
| Asystole | Flat line | Check leads and another lead, then CPR and epinephrine. Do not shock. |
Always treat the patient, not the monitor
A flat line with a talking patient is a loose lead. A "normal" rhythm with no pulse is pulseless electrical activity (PEA), which needs CPR.
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Quick answers
What does atrial fibrillation look like on an EKG?
No clear P waves and an irregularly irregular rhythm.
Can you shock asystole?
No. Asystole is treated with CPR and epinephrine. Defibrillation is for ventricular fibrillation and pulseless ventricular tachycardia.
Evidence & Clinical Sources
- American Heart Association CPR and ECC Guidelines
- Hinkle & Cheever, Brunner & Suddarth's Textbook of Medical-Surgical Nursing, Wolters Kluwer
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For learning only. Lab ranges and policies vary. Always follow your nursing program, a current drug reference, and your facility's policies.