Figure 2: Components of the Ventricular Tachycardia Circuit Identified by Pacing and Entrainment Manoeuvres.

The key components of the VT circuit are identified: the common pathway, outer loop, inner loop through scar tissue, and dead-end activation (C, E, H). Pacing manoeuvres allow identification of these sites in principle, but use in routine mapping of VTs is limited by the stability of the VT and the time taken to pace at multiple sites. CP = common pathway; VT = ventricular tachycardia. Source: Stevenson et al. 1993.8 Reproduced with permission from Wolters Kluwer Health.