Demonstration of a hidden interaction between the aortomitral continuity and the conduction system in a case of idiopathic left ventricular outflow tract ventricular tachycardia.

We describe a case of idiopathic left ventricular outflow ventricular tachycardia. Monomorphic ventricular arrhythmia (VA) with a right bundle branch block morphology and an inferior axis was induced through exercise or isoproterenol infusion. During VA bigeminy, a spiked presystolic potential (PP) preceding the VA with a qrS pattern in the unipolar electrogram was recorded at the aortomitral continuity (AMC). Radiofrequency catheter ablation eliminated the VA despite the persistence of sinus-PP bigeminy. Furthermore, these PP rates were dependent on the preceding sinus rhythm rates. The present case suggests a hidden interaction between the AMC and the conduction system.