Torsades de pointes is most often associated with which condition?

Torsades de pointes is most often associated with which condition?

• A. Prolonged QT interval (QTc greater than 500 ms)
• B. Hyperkalemia
• C. A normal QT interval
• D. Shortened QT interval

Answer: (A)

Torsades de pointes is a polymorphic ventricular tachycardia that occurs most often when repolarization is markedly prolonged. When the QT interval, especially the corrected QT (QTc), is extended—commonly around 500 ms or more—the heart is prone to early afterdepolarizations during the T wave. These afterdepolarizations can trigger the twisting, irregular rhythm characteristic of torsades. Therefore, a prolonged QT interval is the key association. Hyperkalemia changes conduction and causes different ECG patterns, not torsades. A normal or shortened QT interval does not predispose to torsades, so they’re not the typical setting for this arrhythmia.

Torsades de pointes is a polymorphic ventricular tachycardia that occurs most often when repolarization is markedly prolonged. When the QT interval, especially the corrected QT (QTc), is extended—commonly around 500 ms or more—the heart is prone to early afterdepolarizations during the T wave. These afterdepolarizations can trigger the twisting, irregular rhythm characteristic of torsades. Therefore, a prolonged QT interval is the key association.

Hyperkalemia changes conduction and causes different ECG patterns, not torsades. A normal or shortened QT interval does not predispose to torsades, so they’re not the typical setting for this arrhythmia.