Which wave represents total ventricular depolarization and repolarization; prolonged QT indicates risk for Torsades de Pointes?

• A. QRS Complex
• B. T Wave
• C. P Wave
• D. ST Segment

Answer: (B)

Ventricular electrical activity includes depolarization for contraction and repolarization for recovery. The QRS complex reflects ventricular depolarization, while the T wave reflects ventricular repolarization. The QT interval, from the start of the QRS to the end of the T wave, represents the total time for both depolarization and repolarization, and a longer QT interval is a known risk factor for torsades de pointes because it signifies prolonged ventricular repolarization. Among the waves listed, the T wave best represents the ventricular repolarization phase, and the link to torsades comes from the QT prolongation associated with extended repolarization.