Crossroads or "Flyovers" novel insights into ventricular tachycardia mechanisms: The path is twisting.

Diverging channels of activation may be observed in some ventricular tachycardia (VT) using ultra-high-density mapping. We present here cases of such diverging activation patterns as observed from 60 consecutive VT activation maps using the Rhythmia system™ (Boston Scientific, Marlborough, MA, USA). Diverging directions of activation in the same area with "crossroads" or "flyover" pattern can be traced, implying recording of independent multilayer channels. Adaptation of current automated recording by the 3D mapping system is mandatory for better investigating this phenomenon.