When the monitor alarms for real, there is no time to reason from scratch. There is time to follow a method you already know by heart. That method is what you train here — and then you practise it on moving traces, until the answer comes by itself.
No session limit. No card required.
You do not memorise nineteen traces. You ask the same sequence of questions of all of them, and it is the sequence that becomes automatic. People who miss a rhythm almost never miss it because they don't know it — they miss it because they skipped a question.
For each rhythm: the four answers, the sign that settles the diagnosis, what to do, and which other rhythms it is confused with. The confusable pairs are the ones worth training — nobody mistakes asystole for a tachycardia.
What settles the diagnosis: a P before every QRS, rate 60–100, everything regular
What to do: nothing — this is the normal rhythm
Confused with: Sinus Bradycardia, Sinus Tachycardia
What settles the diagnosis: the same as sinus, but under 60
What to do: treat only if perfusion is poor: atropine
Confused with: Normal Sinus Rhythm, Third-degree AV block
What settles the diagnosis: the P is still visible and the rate rarely tops 150 — look for the CAUSE
What to do: treat the cause (pain, fever, hypovolaemia), not the rate
Confused with: Normal Sinus Rhythm, SVT, Atrial Flutter
What settles the diagnosis: too fast and too regular to be sinus, and there is no P
What to do: vagal manoeuvres, adenosine; cardioversion if unstable
Confused with: Sinus Tachycardia, Atrial Flutter, Atrial Fibrillation
What settles the diagnosis: no two intervals are ever the same, and there is no P at all
What to do: rate control, anticoagulation
Confused with: Atrial Flutter, SVT
What settles the diagnosis: a sawtooth baseline — and regular, unlike AF
What to do: rate control, cardioversion
Confused with: Atrial Fibrillation, SVT, Sinus Tachycardia
What settles the diagnosis: wide complexes, all IDENTICAL to each other, and there is a pulse
What to do: synchronised cardioversion; amiodarone
Confused with: Monomorphic VT (pulseless), SVT
What settles the diagnosis: identical to the one above on the strip — what changes is that there is NO pulse
What to do: arrest: defibrillate + ALS
Confused with: Monomorphic VT (with pulse), Coarse VF
What settles the diagnosis: no isoelectric line and every complex different from the last, with NO organised spindle
What to do: defibrillate (unsynchronised); correct ischaemia
Confused with: Torsades de Pointes, Coarse VF, Monomorphic VT (pulseless)
What settles the diagnosis: SPINDLES: the amplitude grows, shrinks and the polarity flips — that is the twist
What to do: magnesium sulfate; correct the long QT
Confused with: Polymorphic VT, Coarse VF
What settles the diagnosis: total chaos, with no recognisable complex at all
What to do: DEFIBRILLATE now
Confused with: Polymorphic VT, Fine VF
What settles the diagnosis: it looks like asystole until you turn up the gain — which is exactly why you do
What to do: defibrillate; high-quality CPR
Confused with: Asystole, Coarse VF
What settles the diagnosis: an essentially flat line — confirm in two leads and with the gain up
What to do: CPR + adrenaline; do NOT defibrillate
Confused with: Fine VF
What settles the diagnosis: there is a rhythm on the monitor but NO pulse — the diagnosis is made on the patient
What to do: CPR + adrenaline; look for the reversible causes
Confused with: Sinus Bradycardia, Third-degree AV block
What settles the diagnosis: every P conducts, but the PR is always long and always the same
What to do: none; monitor
Confused with: Normal Sinus Rhythm, Second-degree AV block, Mobitz I
What settles the diagnosis: the PR keeps LENGTHENING until a beat drops — then it starts over
What to do: monitor; atropine if symptomatic
Confused with: Second-degree AV block, Mobitz II, First-degree AV block
What settles the diagnosis: the PR does not change at all — beats drop suddenly, without warning
What to do: pacing — it can progress to complete heart block
Confused with: Second-degree AV block, Mobitz I, Third-degree AV block
What settles the diagnosis: P waves and QRS each march at their own rate, with no relationship at all
What to do: pacing; atropine rarely works
Confused with: Second-degree AV block, Mobitz II, Sinus Bradycardia
What settles the diagnosis: a thin vertical spike immediately before every complex
What to do: none if it is capturing properly
Confused with: Third-degree AV block, Monomorphic VT (pulseless)
This page gives you the material. What makes it stick is repetition on moving traces, immediate feedback when you get it wrong, and a record of what you keep missing so you can go back to it. That is what sits on the other side of signing up, and it costs nothing.
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