The arrhythmia from QT prolongation is more common in patients with prior cardiac history; which is it?

The arrhythmia from QT prolongation is more common in patients with prior cardiac history; which is it?

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

Answer: (B)

QT prolongation sets the stage for a specific dangerous ventricular tachyarrhythmia: Torsades de Pointes. When the heart’s repolarization is unusually extended, early afterdepolarizations can trigger a rapid, twisting ventricular rhythm. This arrhythmia is often pause- or bradycardia-dependent and can be precipitated by factors common in people with prior cardiac history, such as electrolyte abnormalities, certain drugs, or underlying structural heart disease. On ECG, Torsades de Pointes appears as a polymorphic VT with QRS complexes that twist around the baseline, a distinct pattern that distinguishes it from other rhythms. If not promptly treated, it can degenerate into ventricular fibrillation. The other options don’t have the same direct link to QT duration: a general ventricular tachycardia can arise from various substrates, atrial fibrillation is an atrial rhythm disturbance, and sinus bradycardia is simply a slow heart rate that isn’t itself caused by QT length.

QT prolongation sets the stage for a specific dangerous ventricular tachyarrhythmia: Torsades de Pointes. When the heart’s repolarization is unusually extended, early afterdepolarizations can trigger a rapid, twisting ventricular rhythm. This arrhythmia is often pause- or bradycardia-dependent and can be precipitated by factors common in people with prior cardiac history, such as electrolyte abnormalities, certain drugs, or underlying structural heart disease.

On ECG, Torsades de Pointes appears as a polymorphic VT with QRS complexes that twist around the baseline, a distinct pattern that distinguishes it from other rhythms. If not promptly treated, it can degenerate into ventricular fibrillation.

The other options don’t have the same direct link to QT duration: a general ventricular tachycardia can arise from various substrates, atrial fibrillation is an atrial rhythm disturbance, and sinus bradycardia is simply a slow heart rate that isn’t itself caused by QT length.