bidirectional ventricular tachycardia
A distinctive form of polymorphic ventricular tachycardia with alternating QRS axis, classically associated with digitalis toxicity or catecholaminergic polymorphic VT.
Full Definition
Bidirectional ventricular tachycardia is characterized by QRS complexes that alternate in morphology and axis, creating a distinctive pattern where every other beat appears to point in opposite directions on the ECG. This rhythm is most commonly seen in digitalis toxicity, catecholaminergic polymorphic ventricular tachycardia (CPVT), or severe metabolic derangements. The alternating pattern reflects alternating ventricular activation sequences and carries high risk for degeneration into ventricular fibrillation, requiring immediate recognition and specific treatment of the underlying cause.
Usage
Usage note: Specify the alternating pattern when describing this rhythm to distinguish from other polymorphic VTs.
In Context
- "The rhythm strip showed bidirectional ventricular tachycardia with alternating QRS morphology." — Telemetry interpretation
- "Bidirectional ventricular tachycardia in this patient raised suspicion for digitalis toxicity." — Emergency medicine note