Rhythm recognition
ECG simulator
A live monitor trace generated from waveform maths at standard calibration. Change the rhythm, dial the rate and add movement artefact, then check your read against structured interpretation notes.
How to interpret an ECG, step by step
Rhythm recognition is a habit before it is knowledge. Apply the same six-step read to every strip and the rhythm usually names itself.
Step 1
Calibration and speed
Check 25 mm/s and 10 mm/mV before anything else. One small square is 0.04 s, one large square 0.2 s, so a strip run at the wrong speed makes a normal rate look tachycardic.
Step 2
Rate
Count large squares between two R waves and divide 300 by that number, or count QRS complexes on a 6-second strip and multiply by ten when the rhythm is irregular.
Step 3
Rhythm and regularity
Compare R–R intervals across the strip. Regular, regularly irregular and irregularly irregular each point at a different group of rhythms — atrial fibrillation sits in the last group.
Step 4
P waves and their relationship to QRS
Is there one upright P wave before every QRS, are P waves absent, sawtooth, or more numerous than the QRS complexes? This separates sinus rhythm from flutter, fibrillation and the AV blocks.
Step 5
PR interval and QRS width
A PR interval over 0.2 s or a QRS wider than 0.12 s changes the differential — broad-complex tachycardia is treated as ventricular tachycardia until proven otherwise.
Step 6
Clinical picture and management
Match the trace to the patient: perfusing or not, adverse features present or absent. The rhythm decides whether you follow the Resuscitation Council UK tachycardia, bradycardia or ALS algorithm.
What you practise here
Live monitor simulator
A lead II trace generated from waveform maths rather than scanned images, so the same rhythm can be replayed at any rate with movement artefact dialled in.
- 27 rhythms from sinus rhythm to coarse and fine VF, asystole and PEA
- Rate slider from 0 to 250 bpm with matching NIBP and SpO₂ readings
- Artefact and sweep-speed controls to rehearse reading messy real-world strips
Rhythm recognition quiz
Timed rounds that show a running trace and ask for the rhythm, then score your accuracy so weak rhythm groups surface in your dashboard analytics.
- Core-rhythm rounds for foundation practice, full-catalogue rounds for revision
- Structured interpretation notes after each answer: rate, rhythm, P waves, PR, QRS, management
- Every answer cites JRCALC or Resuscitation Council UK guidance
ECG questions inside the banks
Written questions that pair a rendered rhythm strip with a clinical stem, so recognition is tested alongside the decision that follows it.
- Strip-based items across adult ALS, medical emergencies and cardiac arrest topics
- Rationales that explain why the wrong options are wrong
- Practice mode shows rationales; mock-exam mode withholds them to test recall
ECG practice questions, answered
Simulated traces for education only. Not endorsed by JRCALC or the Royal College of Paramedics; always follow current guidance and your local clinical policy.