What characterizes Torsade's de Pointes?

Torsade's de Pointes is characterized by the distinctive 'twisting' appearance of the QRS complexes on an electrocardiogram (ECG). This phenomenon occurs due to a polymorphic ventricular tachycardia where the amplitude of the QRS complexes changes from beat to beat, creating a pattern that looks like a spiral or twist. This twisting effect is a direct result of the varying axis of ventricular depolarization, which can be associated with prolonged QT interval and certain electrolyte imbalances.

This characteristic twisting is crucial for recognizing Torsade's de Pointes in clinical practice. While a sudden cardiac arrest may occur as a complication, it is not an intrinsic characteristic of the rhythm itself. Similarly, consistent high heart rate may not be observed in all cases, as heart rates can vary widely. The prolonged PR interval is typically associated with different types of heart block, rather than Torsade's de Pointes. Thus, the key diagnostic feature lies in the unique morphology of the QRS complexes.