Ventricular Tachycardia vs Ventricular Fibrillation: With Pulse vs Pulseless — ACLS Decision

Step 1: You see a ventricular rhythm on the monitor — wide QRS, rate ≥ 150 (VT) or chaotic fibrillatory baseline (VFib)

• CHECK THE PULSE IMMEDIATELY — this is always your first action on the NCLEX
• Do not analyze the rhythm further until you know: pulse or no pulse?

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Branch A: PULSE IS PRESENT → This is VT with a pulse

• VFib never has a pulse — if you feel a pulse, it's VT
• Next question: Is the patient stable or unstable?

A1: Stable VT (pulse present, BP adequate, alert, no chest pain)

• Administer amiodarone 150 mg IV over 10 minutes
• Continue telemetry monitoring; prepare for cardioversion if deterioration occurs
• Obtain 12-lead ECG; notify provider
• Do NOT defibrillate — the patient has a pulse and is stable

A2: Unstable VT (pulse present BUT hypotensive, altered mental status, chest pain, or signs of poor perfusion)

• Synchronized cardioversion — start at 100 J biphasic
• Synchronized mode locks the shock to the R wave, avoiding the vulnerable T wave
• Note: if rhythm is polymorphic VT (irregular, varying QRS), treat as VFib — use unsynchronized defibrillation
• Sedate if time and BP allow (midazolam or etomidate)
• Have amiodarone 150 mg IV ready as adjunct after cardioversion
• Key: for monomorphic VT with a pulse — use SYNC, not defib

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Branch B: NO PULSE → Pulseless VT or VFib — treat identically

• Call a code / activate rapid response
• Begin CPR immediately — high-quality compressions 100-120/min, depth 2-2.4 inches
• Defibrillate as soon as the defibrillator is available — unsynchronized shock
  • Biphasic: 120-200 J (use manufacturer recommendation); monophasic: 360 J
• Resume CPR immediately after shock — do NOT stop to check rhythm

After first shock + 2 minutes CPR:

• Check rhythm/pulse
• If still shockable (persistent VFib/pulseless VT):
  • Epinephrine 1 mg IV/IO every 3-5 minutes — give after 2nd shock
  • Defibrillate again

After second shock + 2 minutes CPR:

• If still shockable:
  • Amiodarone 300 mg IV/IO bolus (first dose)
  • Defibrillate again
  • Second amiodarone dose: 150 mg IV/IO if needed

Cycle continues:

• CPR 2 min → rhythm check → shock if shockable → epinephrine every 3-5 min
• Consider reversible causes (H's and T's)

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Critical discrimination points

• Synchronized cardioversion = pulse present + unstable monomorphic VT → shock syncs to R wave
• Defibrillation (unsynchronized) = NO pulse OR polymorphic VT → shock fires immediately
• Amiodarone dose differs: 150 mg (with pulse) vs 300 mg (pulseless/ACLS)
• VFib is always pulseless — you will never choose "stable VFib" on the NCLEX
• Epinephrine is only used in the pulseless algorithm, never for stable or unstable VT with a pulse