ACLS & Cardiology
Rhythms, drugs, and the algorithms — the heart of the written exam.
High-yield before the exam
- Shock the shockable: VF/pVT get defibrillation, not more epi-first debate. Unstable tachy with a pulse gets synchronized cardioversion.
- Epinephrine 1 mg IV/IO every 3–5 minutes in arrest; amiodarone 300 mg then 150 mg for refractory VF/pVT.
- Symptomatic bradycardia ladder: atropine 1 mg → pacing → dopamine/epi drip. High-degree blocks skip atropine.
- Adenosine 6 mg fast push → 12 mg for stable narrow-complex SVT; wide-complex regular tachy = treat as VT.
- 12-lead early: STEMI goes to a cath lab, posterior MI shows ST depression in V1–V3, Sgarbossa reads paced rhythms.
Drug cards12
Dose: Arrest: 1 mg (1:10,000) IV/IO q3–5 min. Anaphylaxis: 0.3–0.5 mg (1:1,000) IM. Push-dose: 5–20 mcg q1–5 min.
Indications
- Cardiac arrest (all rhythms)
- Anaphylaxis
- Symptomatic bradycardia infusion
- Post-ROSC hypotension
Cautions
- Increases myocardial O₂ demand
- Never 1:1,000 IV push in arrest
- Extravasation causes tissue necrosis
EPI
- E — Every 3–5 minutes
- P — Push 1 mg of the dilute (1:10,000)
- I — IM 1:1,000 for anaphylaxis
Pearl: First drug in every arrest rhythm, but it never replaces compressions — CPR is the drug.
Dose: Arrest (VF/pVT): 300 mg IV/IO, then 150 mg. Stable VT: 150 mg over 10 min.
Indications
- Shock-refractory VF/pulseless VT
- Stable wide-complex tachycardia
- Rate control in some AF
Cautions
- Hypotension with fast push
- Bradycardia and QT prolongation
- Avoid with other QT-prolonging drugs
3-1-5
- 300 mg first arrest dose
- 150 mg second dose
- Given after the 3rd shock
Pearl: In arrest it is a rapid push; with a pulse it goes slow, or the pressure drops out from under you.
Dose: 6 mg rapid IV push + 20 mL flush, then 12 mg; may repeat 12 mg.
Indications
- Stable narrow-complex SVT
- Diagnostic unmasking of flutter
Cautions
- Never for irregular/wide (possible WPW AF)
- Asthma — can trigger bronchospasm
- Warn the patient: chest pressure and doom feeling
FAST
- F — Flush hard, 20 mL
- A — Arm up, closest port
- S — Six then twelve
- T — Tell them it feels awful
Pearl: Half-life under 10 seconds. If it did not work, the push was too slow, not the dose too small.
Dose: 1 mg IV q3–5 min, max 3 mg.
Indications
- Symptomatic bradycardia
- Organophosphate poisoning (large doses)
Cautions
- Ineffective in Mobitz II and 3rd-degree block
- Do not delay pacing for it
- Anticholinergic: dry, hot, blind, mad
1-3-3
- 1 mg per dose
- Every 3–5 minutes
- 3 mg total max
Pearl: Symptomatic means hypotension, altered mentation, ischemia or shock — not just a number on the monitor.
Dose: 0.4 mg SL q5 min ×3 (BP permitting). Infusion 5–200 mcg/min.
Indications
- Ischemic chest pain
- Acute pulmonary edema / CHF
- Hypertensive emergency
Cautions
- SBP < 90–100 mmHg
- PDE-5 inhibitors within 24–48 h
- Right-sided / inferior MI with RV involvement
NO VIAGRA
- N — Need a systolic above 90
- O — Only after an IV is in
- V — Viagra/Cialis = hard stop
- R — Right-sided MI = caution
Pearl: Get a right-sided 12-lead on any inferior MI before you spray — a preload-dependent RV will crash.
Dose: 162–324 mg chewed (usually 4 × 81 mg baby aspirin).
Indications
- Suspected ACS
- Chest pain of cardiac origin
Cautions
- True aspirin allergy
- Active GI bleed
- Do not swallow whole — chew it
CHEW
- C — Cardiac chest pain
- H — Have them chew, not swallow
- E — Early, before the 12-lead prints
- W — Watch for allergy or bleed
Pearl: The single prehospital drug with the strongest mortality benefit in ACS. Give it early.
Dose: 2–20 mcg/kg/min. Cardiac 5–10; vasopressor 10–20.
Indications
- Symptomatic bradycardia unresponsive to atropine
- Hypotension / cardiogenic shock
Cautions
- Tachydysrhythmias
- Extravasation necrosis (phentolamine)
- Correct hypovolemia first
Renal-Cardiac-Vaso
- 2–5 = renal dose
- 5–10 = beta / cardiac
- 10–20 = alpha / squeeze
Pearl: Pressors on an empty tank just squeeze air — fill the volume before you chase the number.
Dose: CaCl 1 g (10 mL of 10%) IV slow; gluconate 1–3 g.
Indications
- Hyperkalemia with EKG changes
- Calcium channel blocker overdose
- Hypocalcemia, hypermagnesemia
Cautions
- Never in the same line as bicarb (precipitates)
- Digoxin toxicity — use with caution
- Severe tissue damage if it infiltrates
C BIG K DROP
- C — Calcium (protect the heart)
- B — Bicarb / Beta-agonist
- I — Insulin + glucose
- K — Kayexalate / dialysis
Pearl: Calcium fixes the EKG, not the potassium — you still have to move the K⁺ into the cell.
Dose: 1–2 g IV over 5–20 min (arrest: 1–2 g push).
Indications
- Torsades de pointes
- Refractory VF with suspected hypomagnesemia
- Eclampsia, severe asthma
Cautions
- Hypotension with fast push
- Respiratory depression, loss of reflexes
- Renal failure — accumulates
Twisting = Mag
- Polymorphic + long QT = torsades
- Mag first, defibrillate if pulseless
- Stop the QT-prolonging drug
Pearl: Loss of the patellar reflex is the earliest sign you have given too much.
Dose: 0.25 mg/kg IV over 2 min (≈20 mg), repeat 0.35 mg/kg (≈25 mg).
Indications
- Rate control in AF/flutter with RVR
- Reentrant SVT after adenosine
Cautions
- Never in wide-complex/WPW AF
- Hypotension, heart failure, EF < 40%
- Additive with beta-blockers
SLOW
- S — Stable patients only
- L — Load over 2 minutes
- O — Only narrow and regular-ish
- W — Watch the pressure
Pearl: Irregular + wide + fast? Cardiovert, do not rate-control — you can kill a WPW patient with the AV nodal blocker.
Dose: 1–1.5 mg/kg IV, repeat 0.5–0.75 mg/kg q5–10 min (max 3 mg/kg).
Indications
- VF/pVT alternative to amiodarone
- Stable monomorphic VT
Cautions
- Neuro toxicity: tinnitus, twitching, seizures
- Reduce dose in liver failure/low output
- Bradycardia and heart block
1.5 / 0.75 / 3
- 1–1.5 mg/kg first dose
- 0.5–0.75 mg/kg repeats
- 3 mg/kg total ceiling
Pearl: The first sign of toxicity is neurological, not cardiac — listen for ringing ears and slurred speech.
Dose: 0.05–0.5 mcg/kg/min titrated to MAP ≥ 65.
Indications
- Septic and cardiogenic shock
- Post-ROSC hypotension
Cautions
- Central line preferred; watch peripheral site
- Reflex bradycardia
- Ischemia in end vessels
Levo = Leave the pressure up
- First-line for most shock
- Titrate to MAP, not systolic
- Fix volume alongside it
Pearl: MAP ≥ 65 is the target because that is the pressure the kidneys and brain actually perfuse at.
Rhythms to know15
Sinus Bradycardia · < 60
- Normal P waves
- Regular
- Slow
Action: Symptomatic → atropine 1 mg, then pacing / dopamine / epi drip.
Sinus Tachycardia · 100–150
- P before every QRS
- Regular
- Gradual onset
Action: Find and fix the why: pain, fever, hypovolemia, hypoxia.
SVT · 150–250
- Narrow, very fast, regular
- P waves buried in T
- Abrupt onset
Action: Vagal → adenosine 6/12/12 → sync cardioversion if unstable.
Atrial Fibrillation (RVR) · Variable, often > 100
- No P waves
- Irregularly irregular
- Fibrillatory baseline
Action: Stable → rate control. Unstable → synchronized cardioversion.
Atrial Flutter · Ventricular ~150
- Sawtooth waves
- Regular
- 2:1 conduction classic
Action: Rate control or sync cardioversion if unstable.
Ventricular Tachycardia · 100–250
- Wide, bizarre QRS
- Regular
- No P waves
Action: Pulse + stable → amiodarone. Pulse + unstable → sync. No pulse → defibrillate.
Torsades de Pointes · 200–250
- Polymorphic VT
- QRS twists around baseline
- Long QT
Action: Magnesium 1–2 g. Pulseless → defibrillate.
Ventricular Fibrillation · Chaotic
- No identifiable waves
- Chaotic baseline
- No pulse
Action: CPR + defibrillate now. Epi q3–5, amio 300 after 3rd shock.
Asystole · 0
- Flat line
- No pulse
- Confirm in 2 leads
Action: CPR + epi. Do NOT shock. Hunt the H's and T's.
PEA · Any organized rate
- Organized complexes
- No pulse
- Often wide and slow
Action: CPR + epi + reversible causes. Not shockable.
3rd-Degree AV Block · Escape 20–40
- P's march independently
- No PR relationship
- Wide escape beats
Action: Pace. Atropine usually will not work.
1st-Degree AV Block · Usually 60–100
- PR > 0.20 s
- Every P conducts
- Regular
Action: Usually benign. Watch for progression and check meds.
Junctional Rhythm · 40–60 (accelerated 60–100)
- Absent, inverted or retrograde P waves
- Narrow QRS
- Regular
Action: Treat symptoms and look for digoxin toxicity or ischemia.
Idioventricular / Agonal · 20–40 or less
- Wide bizarre QRS
- No P waves
- Very slow
Action: Often a pre-arrest or post-ROSC rhythm. Check a pulse, treat causes, pace if perfusing poorly.
Paced Rhythm · Set by the device
- Pacer spikes before P or QRS
- Wide QRS after ventricular spikes
- Regular
Action: Assess capture: every spike needs a matching complex and a pulse.
Field cases1
Diaphoretic, grey, clutching his sternum. Pain started 40 minutes ago while lifting bags of mulch.
Vitals: BP 92/58 · HR 48 · RR 22 · SpO₂ 96% RA
Monitor: Sinus bradycardia. 12-lead: ST elevation in II, III, aVF.
Skills to drill8
IV access
Mastery: Hits an AC or forearm vein in two sticks or fewer, clean securement, first-try above 70%.
Drill: Ten sticks a week on the trainer arm; verbalize vein selection out loud each time.
IO access (EZ-IO)
Mastery: Proximal humerus or tibial IO in under 60 seconds during an arrest, flush under pressure.
Drill: Arrest sim: drill, secure, pressure-bag flush, and run epi through it inside 2 minutes.
High-performance CPR
Mastery: 100–120/min, 2-inch depth, full recoil, compressor swap under 5 seconds, 60%+ fraction.
Drill: Metronome drill: 2 minutes on, swap mid-count, zero lean on the feedback device.
Defibrillation & cardioversion
Mastery: Pads on and first shock inside 90 seconds of arrival; syncs for unstable tachy without being asked.
Drill: Verbalize the charge-clear-shock sequence while compressions continue to last second.
Transcutaneous pacing
Mastery: Pads, rate 60–80, milliamps up until mechanical capture — confirmed by pulse, not just spikes.
Drill: On the trainer: find capture threshold, then palpate a femoral pulse to prove capture.
12-lead acquisition
Mastery: Clean, artifact-free 12-lead in under 5 minutes — V4R and posterior leads when the story calls for them.
Drill: Do V4R on every inferior STEMI practice strip until it is muscle memory.
Rhythm & 12-lead interpretation
Mastery: Calls the rhythm in 10 seconds, spots STEMI, Wellens, de Winter, and Sgarbossa in paced rhythms.
Drill: Ten strips a day. Say rate, rhythm, intervals, and axis out loud before looking at the answer.
Medication math
Mastery: Computes drips, weight-based doses, and push-dose pressors without a calculator under pressure.
Drill: Five drip problems before every shift: dopamine, epi, amiodarone, lidocaine, weight-based peds.
Board-style exam questions48
1. Adult in witnessed VF arrest. Highest-priority intervention?
2. Inferior STEMI with hypotension and clear lungs. Which drug is contraindicated?
3. Stable narrow-complex regular tachycardia at 190 after vagal maneuvers fail. Next?
4. Adult compression depth and rate?
5. Symptomatic bradycardia at 38 unresponsive to atropine. Next step?
6. Torsades de pointes with a pulse. Drug of choice?
7. PEA arrest in a dialysis patient who missed treatment. Most likely reversible cause?
8. Post-ROSC care priority?
9. Chest pain patient with a true aspirin allergy. Best action?
10. Cardiac arrest in a third-trimester pregnancy. Key modification?
11. Hypothermic arrest at 26°C still in VF after one shock. Approach?
12. STEMI identified 90 minutes from the nearest PCI center. Priority action?
13. Beck's triad suggests which reversible arrest cause?
14. Best available measure of compression quality during a code?
15. Unstable wide-complex tachycardia with a pulse and a systolic of 70. Treatment?
16. New-onset atrial fibrillation at 150, stable, onset 2 hours ago. Prehospital priority?
17. Epinephrine dose and interval in adult cardiac arrest?
18. Refractory VF after three shocks. Preferred antiarrhythmic?
19. Which 12-lead finding suggests posterior MI?
20. Pediatric arrest is most commonly caused by:
21. A patient took sildenafil 6 hours ago and has chest pain. Which is contraindicated?
22. Hyperkalemia on the monitor most classically shows:
23. During CPR, when should the rhythm be checked?
24. Suspected cocaine-associated chest pain. Which drug class is avoided?
25. Adult unwitnessed arrest found in asystole. Priority?
26. Symptomatic bradycardia unresponsive to atropine. Next step?
27. Stable narrow-complex regular SVT after vagal maneuvers fail?
28. Unstable atrial fibrillation with hypotension and chest pain. Treatment?
29. Inferior STEMI with hypotension. Which drug is most dangerous?
30. Torsades de pointes with a pulse. First drug?
31. Refractory VF after three shocks and epinephrine. Next drug?
32. Target compression depth and rate for an adult?
33. Beck's triad suggests:
34. PEA arrest in a dialysis patient with peaked T waves before arrest. Give:
35. Post-ROSC blood pressure target?
36. Cardiogenic shock with pulmonary edema. Which is most appropriate?
37. Aspirin dose in suspected ACS?
38. A 12-lead shows ST elevation in V1–V4. Which wall?
39. Pulseless electrical activity most commonly results from:
40. Hands-off time between compressions and shock should be:
41. A 6-year-old child in cardiac arrest. Compression depth and rate?
42. Two-rescuer CPR compression-to-ventilation ratio for a child with no advanced airway?
43. First defibrillation energy for pediatric VF?
44. Adult in PEA at a rate of 30 after a long extrication under concrete. Most likely reversible cause?
45. The single most important quality metric during CPR is:
46. ETCO2 during CPR abruptly jumps from 12 to 42 mmHg. Interpretation?
47. Symptomatic bradycardia in a child at a heart rate of 48 with poor perfusion despite oxygen and ventilation. Next step?
48. Post-ROSC blood pressure goal in an adult?
Keep going
Educational review only — always follow your local protocols and medical direction. Not affiliated with or endorsed by the NREMT.