Tachycardia Termination Without Global Propagation: Is the Pacing Site In or Out?

Ventricular tachycardia termination by pacing with non-global capture is a specific criterion for identifying a critical component of the re-entrant circuit, regardless of whether concealed entrainment can be demonstrated at that site. It is usually observed almost by chance, but it can also be intentionally demonstrated by introducing a single extrastimulus during tachycardia.