A 40-year-old male is found unresponsive. CPR is in progress. The cardiac monitor shows a wide, irregular rhythm with varying QRS morphology. There is no palpable pulse. What is the MOST likely rhythm and appropriate immediate intervention?
- ATorsades de Pointes; administer magnesium sulfate 2 g IV.
- BPolymorphic ventricular tachycardia (PVT); immediate defibrillation.
- CAsystole; administer epinephrine 1 mg IV.
- DVentricular fibrillation (VF); immediate defibrillation.
Show answer & explanationAnswer & explanation
Correct answer: B. Polymorphic ventricular tachycardia (PVT); immediate defibrillation.
A wide, irregular rhythm with varying QRS morphology in a pulseless patient is characteristic of polymorphic ventricular tachycardia (PVT). PVT, like VF, is a shockable rhythm in cardiac arrest and requires immediate defibrillation. While Torsades de Pointes is a form of PVT, the immediate intervention for a pulseless patient is defibrillation, not magnesium, which is for stable or unstable Torsades with a pulse.
Why the other options are wrong
- A. Magnesium is for Torsades de Pointes, but the immediate intervention for pulseless Torsades (a type of PVT) is defibrillation, not magnesium first.
- C. Asystole is a flatline, not a wide irregular rhythm.
- D. VF is a wide, irregular rhythm, but often described as chaotic, not necessarily 'varying QRS morphology' in the same way PVT is. However, the treatment is the same: defibrillation.
Polymorphic Ventricular Tachycardia (PVT)
A type of ventricular tachycardia characterized by a wide QRS complex that varies in shape and amplitude. If pulseless, it is a cardiac arrest rhythm and is treated with immediate defibrillation.
- Often associated with underlying cardiac disease or electrolyte imbalances.
- Pulseless PVT is treated as VF: immediate defibrillation.
- Torsades de Pointes is a specific type of PVT associated with QT prolongation.
Memory trick: Irregular Wide + Pulseless: 'Shock It' before 'Seeking Specifics'!