Read any strip in 5 steps
Same order, every time. No panic, no guessing.
The 18 rhythms you must know cold
Each card: what it looks like, how to picture it, and what to actually do on scene.
Rate: 60–100
Spot it:
- P before every QRS
- Regular
- Narrow QRS
🧠 Picture this: A metronome ticking politely — every P has a partner.
On scene: Monitor. Treat the patient, not the box.
Rate: < 60
Spot it:
- Normal P waves
- Regular
- Slow
🧠 Picture this: A turtle wearing a heart monitor, strolling.
On scene: Symptomatic → atropine 1 mg, then pacing / dopamine / epi drip.
Rate: 100–150
Spot it:
- P before every QRS
- Regular
- Gradual onset
🧠 Picture this: A runner with a fever chasing a cause, not a rhythm.
On scene: Find and fix the why: pain, fever, hypovolemia, hypoxia.
Rate: 150–250
Spot it:
- Narrow, very fast, regular
- P waves buried in T
- Abrupt onset
🧠 Picture this: A record skipping so fast the label blurs.
On scene: Vagal → adenosine 6/12/12 → sync cardioversion if unstable.
Rate: Variable, often > 100
Spot it:
- No P waves
- Irregularly irregular
- Fibrillatory baseline
🧠 Picture this: A wobbly shopping cart wheel that never repeats its rhythm.
On scene: Stable → rate control. Unstable → synchronized cardioversion.
Rate: Ventricular ~150
Spot it:
- Sawtooth waves
- Regular
- 2:1 conduction classic
🧠 Picture this: A saw blade cutting a straight line through the baseline.
On scene: Rate control or sync cardioversion if unstable.
Rate: 100–250
Spot it:
- Wide, bizarre QRS
- Regular
- No P waves
🧠 Picture this: Shark fins in a row — wide, fast, and coming for you.
On scene: Pulse + stable → amiodarone. Pulse + unstable → sync. No pulse → defibrillate.
Rate: 200–250
Spot it:
- Polymorphic VT
- QRS twists around baseline
- Long QT
🧠 Picture this: A ribbon twisting around a pole.
On scene: Magnesium 1–2 g. Pulseless → defibrillate.
Rate: Chaotic
Spot it:
- No identifiable waves
- Chaotic baseline
- No pulse
🧠 Picture this: A bag of worms dumped on the monitor.
On scene: CPR + defibrillate now. Epi q3–5, amio 300 after 3rd shock.
Rate: 0
Spot it:
- Flat line
- No pulse
- Confirm in 2 leads
🧠 Picture this: A desert horizon — nothing for miles.
On scene: CPR + epi. Do NOT shock. Hunt the H's and T's.
Rate: Any organized rate
Spot it:
- Organized complexes
- No pulse
- Often wide and slow
🧠 Picture this: A puppet heart on strings — it looks alive on screen only.
On scene: CPR + epi + reversible causes. Not shockable.
Rate: Escape 20–40
Spot it:
- P's march independently
- No PR relationship
- Wide escape beats
🧠 Picture this: Two drummers in the same room refusing to look at each other.
On scene: Pace. Atropine usually will not work.
Rate: Usually 60–100
Spot it:
- PR > 0.20 s
- Every P conducts
- Regular
🧠 Picture this: A mail carrier who always delivers, just always late.
On scene: Usually benign. Watch for progression and check meds.
Rate: Often 40–70
Spot it:
- PR lengthens then a QRS drops
- Grouped beating
- Narrow QRS
🧠 Picture this: A runner getting slower each lap until they skip one entirely.
On scene: Symptomatic → atropine. Often responds well.
Rate: Slow, variable
Spot it:
- Constant PR, sudden dropped QRS
- Often wide QRS
- Can march to complete block
🧠 Picture this: An elevator that skips floors with no warning.
On scene: Pace. Atropine usually fails and can worsen it.
Rate: 40–60 (accelerated 60–100)
Spot it:
- Absent, inverted or retrograde P waves
- Narrow QRS
- Regular
🧠 Picture this: The backup generator kicking on when the main power fails.
On scene: Treat symptoms and look for digoxin toxicity or ischemia.
Rate: 20–40 or less
Spot it:
- Wide bizarre QRS
- No P waves
- Very slow
🧠 Picture this: A candle down to its last flicker.
On scene: Often a pre-arrest or post-ROSC rhythm. Check a pulse, treat causes, pace if perfusing poorly.
Rate: Set by the device
Spot it:
- Pacer spikes before P or QRS
- Wide QRS after ventricular spikes
- Regular
🧠 Picture this: A drummer with a click track in their ears.
On scene: Assess capture: every spike needs a matching complex and a pulse.
Memory tricks that stick
“If the R is far from P, you have a first degree”
1st-degree AV block — long PR, but every beat conducts.
“Longer, longer, longer, DROP — that's a Wenckebach”
2nd-degree Type I — PR stretches until a beat disappears.
“If some P's don't get through, that's a Mobitz II”
2nd-degree Type II — constant PR with sudden dropped beats.
“If the P's and Q's don't agree, you have a third degree”
3rd-degree block — atria and ventricles beat independently.
“Shark fins in a row = VT, time to go”
Wide regular fast complexes with no P waves.
“Bag of worms on the screen = V-fib, shock between”
Chaotic baseline, no pulse — CPR and defibrillate.
“Saw blade on the line = flutter's design”
Atrial flutter sawtooth, classically at 150 (2:1 block).
“Wobbly wheel, no repeats = afib's beats”
Irregularly irregular, no P waves, fibrillatory baseline.
Field application quiz
Six real-scene scenarios. Pick your move, get the why, no score saved anywhere.
Quick answers
Educational resource only — always follow your local protocols and medical direction.