Entrainment Pacing: A Diagnostic Tool for Reentrant Tachycardia and Its Application for Catheter Ablation

Entrainment is one of the most important fundamentals of electrophysiologic testing. It is used as a tool for diagnosing reentry as a mechanism of tachycardias, localizing and charactering the reentry circuit including slow conduction zone (SCZ), and identifying a target site for catheter ablation. There are two types of entrainment, manifest and concealed entrainment, and it is quite important to understand accurately their mechanisms, influential factors to them, and how to apply them in the target tachycardias. Manifest entrainment is mainly used for diagnosing reentry as a mechanism of tachycardia, and concealed entrainment is for identifying the SCZ or critical isthmus in the reentry circuit for ablation.