QT Interval — ECG/EKG Terminology

Definition: The time from the start of the QRS complex to the end of the T wave, representing total ventricular depolarization and repolarization.

Key Facts

• Represents total ventricular depolarization and repolarization duration.
• Should be corrected for heart rate (QTc) when assessing risk.
• Prolonged QT increases risk of torsades de pointes and malignant ventricular arrhythmia.

ECG Connection: QT monitoring is essential when patients receive QT-prolonging drugs or have electrolyte abnormalities.

Why It Matters: Rising QTc can precede sudden ventricular arrhythmias.