EKG

Wide-complex tachycardias & VT/VF

EKG

Wide-complex tachycardias & VT/VF

VT vs SVT with aberrancy, torsades, VF — and what to shock vs not.

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◆Assume VT until proven otherwise

•ANY wide-complex tachycardia (QRS >120 ms) in a patient with known CAD or HF = VT until proven otherwise
•Monomorphic VT: regular, uniform wide QRS — usually scar-based (post-MI)
•Polymorphic VT: changing QRS morphology; if QT long → Torsades de Pointes
•VFib: chaotic, no organized QRS — pulseless
•Pulseless VT/VFib → defibrillate (UNsynchronized), epinephrine every 3–5 min, amiodarone after 2nd–3rd shock

◆Stable vs unstable VT

•Unstable (pulse but hypotensive/AMS/CP) → synchronized cardioversion
•Stable VT with pulse → amiodarone or procainamide IV; sotalol alternative
•Pulseless VT → defibrillation per ACLS

◆Torsades de Pointes

•Polymorphic VT with QT prolongation; sinusoidal 'twisting' baseline
•Causes: hypoK, hypoMg, hypoCa, congenital long QT, drugs (Class IA/III antiarrhythmics, macrolides, fluoroquinolones, methadone, ondansetron, antipsychotics)
•Treat: IV magnesium sulfate; correct electrolytes; pace or isoproterenol to ↑ HR (shortens QT)

Wide-complex tach decoder

Pattern	Action
Monomorphic VT, stable	Amiodarone or procainamide IV
Monomorphic VT, unstable	Synchronized cardioversion
Pulseless VT / VFib	Defibrillate (unsynchronized), CPR, epi, amiodarone
Torsades (long QT)	IV magnesium, correct K/Mg, pace if recurrent
AFib with WPW	Procainamide; AVOID AV nodal blockers

High-yield pearls

◆Never treat wide-complex tach with verapamil/diltiazem — could be VT and cause arrest
◆Magnesium first-line for torsades regardless of serum Mg level
◆VFib + unwitnessed/unsuccessful resuscitation > 20 min → consider therapeutic hypothermia post-ROSC for neuro protection (32–36°C × 24 hr)

Quick check

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