What is a notable feature of the QRS interval in torsades de pointes?

• A. It is long and stable
• B. It spirals around the isoelectric line and changes polarity
• C. It is consistently narrow
• D. It can be measured easily

Answer: (B)

In the context of torsades de pointes, a notable feature of the QRS interval is that it spirals around the isoelectric line and changes polarity. This characteristic is indicative of the distinctive "twisting" appearance of the QRS complexes seen on an electrocardiogram (ECG) during this specific type of polymorphic ventricular tachycardia. Torsades de pointes translates to "twisting of the points," which aptly describes the visual effect observed during this arrhythmia.

This twisting pattern occurs due to rapid oscillations between different axes of depolarization, leading to alternating positive and negative deflections of the QRS complexes as they vary in morphology and duration. It serves as a key diagnostic feature, helping clinicians identify this specific arrhythmia, which often arises due to electrolyte imbalances, medications, or a congenital long QT syndrome.

Understanding this distinctive feature is crucial in telemetry, as it assists healthcare providers in recognizing torsades de pointes, allowing for appropriate and timely intervention.