Resetting and entrainment of reentrant ventricular tachycardia associated with myocardial infarction.

Resetting and entrainment are specific responses to programmed stimulation that are useful in determining the mechanism of ventricular tachycardia (VT), localizing critical components of a reentrant circuit to guide ablation, determining how antiarrhythmic drugs affect the tachycardia, and developing antitachycardia pacing modalities. While resetting and entrainment have certain things in common, they differ significantly in the ability to characterize the properties of VT. Only resetting, which is the interaction of a single extrastimulus with the tachycardia, can characterize the properties of the VT itself. Entrainment assesses the effect of overdrive pacing on a reset circuit, not the VT itself. The terms for these techniques are often incorrectly used interchangeably. The present review details the characteristics and uses of both stimulation techniques.