What is torsades de pointes and its relation to QT prolongation?

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Multiple Choice

What is torsades de pointes and its relation to QT prolongation?

Torsades de pointes is a specific form of polymorphic ventricular tachycardia that arises when the QT interval is prolonged, reflecting extended repolarization of the ventricles. The longer repolarization window allows early afterdepolarizations to trigger impulses during late repolarization, which can initiate a run of twisting, irregular QRS complexes—the hallmark appearance of torsades, as the QRS morphology seems to swing around the baseline from beat to beat. This rhythm is commonly triggered by acquired QT prolongation from certain drugs (like some antiarrhythmics, antibiotics, or antipsychotics) or by electrolyte disturbances (low potassium or magnesium), and can also occur in congenital long QT syndromes. It can deteriorate into ventricular fibrillation if not treated promptly, so recognizing the link between QT prolongation and this polymorphic VT is crucial. Other options describe rhythms that do not involve a polymorphic VT with twisting QRS around baseline. A rapid atrial rhythm with regular P waves is an atrial tachyarrhythmia, a monomorphic VT after an anterior MI shows a single consistent QRS morphology, and sinus rhythm with frequent PACs represents early atrial activity on a normal rhythm.

Torsades de pointes is a specific form of polymorphic ventricular tachycardia that arises when the QT interval is prolonged, reflecting extended repolarization of the ventricles. The longer repolarization window allows early afterdepolarizations to trigger impulses during late repolarization, which can initiate a run of twisting, irregular QRS complexes—the hallmark appearance of torsades, as the QRS morphology seems to swing around the baseline from beat to beat.

This rhythm is commonly triggered by acquired QT prolongation from certain drugs (like some antiarrhythmics, antibiotics, or antipsychotics) or by electrolyte disturbances (low potassium or magnesium), and can also occur in congenital long QT syndromes. It can deteriorate into ventricular fibrillation if not treated promptly, so recognizing the link between QT prolongation and this polymorphic VT is crucial.

Other options describe rhythms that do not involve a polymorphic VT with twisting QRS around baseline. A rapid atrial rhythm with regular P waves is an atrial tachyarrhythmia, a monomorphic VT after an anterior MI shows a single consistent QRS morphology, and sinus rhythm with frequent PACs represents early atrial activity on a normal rhythm.

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