Key result
Reported bidirectional VT is likely misdiagnosed sinus rhythm with ventricular bigeminy from intraventricular conduction delay.
Why the study?
Hypokalemia-induced bidirectional ventricular tachycardia is rarely reported and studied, prompting a re-evaluation of a reported case to provide an alternative explanation.
Careful comparison of tachycardic ECGs with baseline ECGs is crucial to avoid misdiagnosing ventricular bigeminy with aberrancy as bidirectional ventricular tachycardia.
Requires baseline ECG comparison to avoid misdiagnosing ventricular bigeminy as bidirectional VT; challenges prior case reports and leaves classification open.
Bidirectional ventricular tachycardia is a rare ventricular arrhythmia characterized by alternatingQRS morphology on the electrocardiogram. We comment on and provide an alternativeexplanation for a reported case of hypokalemia-induced bidirectional ventricular tachycardia, aphenomenon rarely reported and studied in the literature. Analysis of the electrocardiogramduring the tachycardic episode compared to the baseline electrocardiogram demonstratessignificant similarities in mean electrical axis and QRS morphology, as well as a lack of clearatrioventricular dissociation. In considering the electrocardiographic features as well as thepatient’s clinical history, the rhythm is more consistent with sinus rhythm in the presence of anintraventricular conduction delay with ventricular bigeminy. This case highlights the importanceof critically analyzing suspected bidirectional ventricular tachycardia and emphasizes the valueof utilizing baseline electrocardiograms for comparison and diagnosis.
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Johnson et al. (2026) studied this question. The reported case of bidirectional ventricular tachycardia is likely misdiagnosed and is instead consistent with sinus rhythm and ventricular bigeminy due to intraventricular conduction delay.
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