MedBalans

Emergency Arrhythmias

Adults · emergency only · brief protocol

Algorithm

  1. Check responsiveness and pulse; start CPR if pulseless; attach defibrillator/monitor early.
  2. Identify rhythm class: shockable (VF/pVT) vs non-shockable (PEA/asystole) vs bradycardia vs tachycardia with pulse.
  3. Follow the matching form protocol below — do not mix algorithms.
  4. Give oxygen, obtain IV/IO access, treat reversible causes (4H and 4T).
  5. After ROSC or rate control: 12-lead ECG, bloods, seek expert help / CCU-ICU.

Red flags

  • • No pulse — arrest algorithm first, not oral antiarrhythmics
  • • Unstable tachycardia with pulse — cardioversion, not prolonged drug trials
  • • Mobitz II / complete AV block — prepare pacing
  • • Consider toxins / hyperkalemia / ACS

Medications by step

Overview — key adult doses

  • Adrenaline · i.v. / i.o.

    Arrest: 1 mg IV/IO q3–5 min; bradycardia infusion 2–10 mcg/min

  • Amiodarone · i.v.

    Arrest VF/pVT: 300 mg then 150 mg; stable VT: 300 mg over 10–60 min

  • Atropine · i.v.

    Bradycardia: 500 mcg IV; repeat to max 3 mg

Help by rhythm form

Separate short protocols for each emergency rhythm — follow the form you see on the monitor.

VF / pulseless VT

  1. Confirm cardiac arrest → high-quality CPR; minimize interruptions; attach defibrillator.
  2. Shock as soon as ready: ≥150 J biphasic (or manufacturer dose); immediately resume CPR 2 min; peri-shock pause <5 s.
  3. After a total of 3 shocks: adrenaline 1 mg IV/IO; then every 3–5 min (ERC 2025 — not after the 2nd shock).
  4. After a total of 3 shocks: amiodarone 300 mg IV/IO; after a total of 5 shocks: amiodarone 150 mg (refractory or recurrent VF/pVT).
  5. If amiodarone unavailable: lidocaine 100 mg IV, then 50 mg after 5 shocks.
  6. Refractory VF after 3 shocks: confirm mid-axillary pad position; consider antero-posterior pad vector change (ERC 2025). Dual sequential defibrillation is not routinely recommended.
  7. Between cycles: airway/oxygenation, prefer IV access first, treat 4H/4T.

Red flags

  • • Refractory VF after ≥3 shocks — seek 4H/4T, hyperK, ACS, toxins
  • • Long CPR pauses for intubation

Medications by step

Defibrillation

  • Defibrillation · —

    150–200 J biphasic; CPR 2 min between shocks

Arrest drugs

  • Adrenaline · i.v. / i.o.

    1 mg IV/IO after 3rd shock, then q3–5 min

  • Amiodarone · i.v. / i.o.

    300 mg IV/IO after 3 shocks; 150 mg after 5 shocks

  • Lidocaine · i.v.

    100 mg IV if no amiodarone; +50 mg after 5 shocks

PEA / asystole

  1. Non-shockable rhythm: do NOT defibrillate. Continuous high-quality CPR.
  2. Adrenaline 1 mg IV/IO as soon as possible, then every 3–5 min.
  3. Confirm asystole in ≥2 leads; check leads/pads; treat PEA as organized ECG without pulse.
  4. Aggressively reverse 4H/4T (hypoxia, hypovolemia, hypo/hyperkalemia, hypothermia; thrombosis, tamponade, toxins, tension pneumothorax).
  5. Reassess rhythm every 2 min; if VF/pVT appears → switch to shockable algorithm.

Red flags

  • • False asystole from disconnected leads
  • • Missing reversible causes (hypovolemia, tension PTX, PE, hyperK)

Medications by step

PEA / asystole drugs

  • Adrenaline · i.v. / i.o.

    1 mg IV/IO ASAP, then q3–5 min

Symptomatic bradycardia

  1. Assess ABCs, oxygen if hypoxic, IV access, 12-lead ECG when stable enough.
  2. Unstable signs: shock, syncope, acute heart failure, ischemic chest pain, altered mentation → treat immediately.
  3. Atropine 500 mcg IV; repeat every 3–5 min to max 3 mg.
  4. If atropine fails or high-degree block: prepare transcutaneous pacing; sedation/analgesia if conscious.
  5. Second-line infusions: adrenaline 2–10 mcg/min IV or isoprenaline/dopamine per local protocol while arranging TCP/TVP.
  6. Seek expert help early for AV block, acute MI, or toxin-related bradycardia.

Red flags

  • • Mobitz II / complete AV block — do not rely on atropine alone
  • • ACS as the cause

Medications by step

Bradycardia therapy

  • Atropine · i.v.

    500 mcg IV q3–5 min; max 3 mg

  • Adrenaline infusion · i.v. infusion

    2–10 mcg/min IV if atropine/pacing insufficient

  • Transcutaneous pacing · —

    Capture then set rate ~60–70/min; check pulse

Unstable tachycardia (with pulse)

  1. Confirm pulse present but patient unstable (shock, ischemia, acute HF, severe hypotension, altered mentation).
  2. Synchronized cardioversion: sedation if conscious; energy per local protocol (often start ~70–120 J biphasic for narrow regular; higher for irregular/wide).
  3. If VT with pulse and unstable → synchronized cardioversion (not defibrillation unless pulseless).
  4. If delays to cardioversion and regular narrow-complex: adenosine 6 mg rapid IV push may be diagnostic/therapeutic while preparing shock.
  5. After conversion: 12-lead ECG, treat cause (ischemia, electrolytes, drugs), monitor for recurrence.

Red flags

  • • Pulse lost while preparing → switch to arrest algorithm
  • • Unsynchronized shock with a pulse risks inducing VF

Medications by step

Unstable tachycardia

  • Synchronized cardioversion · —

    Per device/protocol; escalate energy if fails

  • Adenosine · i.v.

    6 mg rapid IV flush (optional while preparing shock if regular narrow)

Stable narrow-complex tachycardia / AF with RVR

  1. Confirm stability (adequate BP/perfusion, no severe ischemia/acute HF).
  2. Regular narrow (likely AVNRT/AVRT): vagal maneuvers → adenosine 6 mg rapid IV, then 12 mg if needed (max per protocol).
  3. Irregular narrow (AF/flutter with RVR): rate control if duration unknown or >48 h without anticoagulation plan — beta-blocker or nondihydropyridine CCB IV per local protocol; digoxin if HF/hypotension risk with those agents.
  4. Avoid routine immediate cardioversion for stable AF of unknown duration without anticoagulation / TEE strategy.
  5. Wide-complex stable tachycardia: treat as VT until proven otherwise — expert help; amiodarone 300 mg IV over 10–60 min often used; avoid AV-nodal blockers if accessory pathway suspected (pre-excited AF).

Red flags

  • • Pre-excited AF (WPW) — do not use verapamil/digoxin/adenosine for rate control
  • • Becomes unstable → cardioversion

Medications by step

Stable SVT / AF RVR

  • Adenosine · i.v.

    6 mg rapid IV; then 12 mg if needed (regular narrow)

  • Metoprolol / esmolol or verapamil / diltiazem · i.v.

    IV rate control for AF RVR per local protocol if stable

  • Amiodarone · i.v.

    300 mg IV over 10–60 min for stable wide-complex VT suspected

References

  • • ERC Guidelines 2025 — Adult ALS (2025)
  • • AHA — ACLS algorithms (2020)

Updated: Июль 2026