Which rhythm is described as ventricular tachycardia with amplitude that fluctuates around the isoelectric line?

• A. Ventricular fibrillation
• B. Atrial flutter
• C. Torsades de Pointes
• D. Sinus tachycardia

Answer: (C)

Torsades de Pointes is a polymorphic ventricular tachycardia in which the QRS complexes appear to twist around the baseline, so their amplitude rises and falls beat to beat as the axis shifts. That changing amplitude around the isoelectric line is the defining feature you’re seeing. This pattern sets it apart from other rhythms: ventricular fibrillation is completely chaotic with no distinct QRS complexes; atrial flutter shows sawtooth atrial waves rather than a twisting ventricular pattern; and sinus tachycardia is a fast but regular rhythm with normal, steady QRS complexes. Torsades is often linked to a prolonged QT, and can be triggered by electrolyte disturbances or certain drugs.