Ablation of electrograms with an isolated, delayed component as treatment of unmappable monomorphic ventricular tachycardias in patients with structural heart disease.

Objectives: We sought to evaluate the feasibility of identifying and ablating the substrate of unmappable ventricular tachycardia (VT).

Background: Noninducible and nonstable VT cannot be ablated by the conventional approach.

Methods: We studied 24 patients with documented monomorphic VT.