What characterizes bidirectional ventricular tachycardia?

Bidirectional ventricular tachycardia is characterized by alternating QRS complex morphology, which means that the shape of the QRS complexes varies consistently throughout the rhythm. This distinctive feature occurs due to differing electrical conduction patterns in both ventricles, often related to the presence of varying vectors of depolarization. In this arrhythmia, the alternating morphology points to a dynamic and unique underlying mechanism, usually involving a trigger or a substrate such as digoxin toxicity or certain forms of ischemia.

While consistency in morphology is representative of other arrhythmias, bidirectional VT stands out specifically because of its alternating appearance. The absence of P waves is a common trait in many ventricular arrhythmias but does not define bidirectional VT alone. Rapid heart rate with normal conduction would not be characteristic of this condition, as the hallmark of bidirectional ventricular tachycardia is the alternating pattern of the QRS complexes, which signifies the presence of an underlying mechanism distinct from normal conduction pathways. This understanding is crucial when diagnosing and managing patients with this specific arrhythmia.