Entrainment response in a model of reentrant tachycardia

Studies suggest that entrainment response (ER) of reentrant tachycardia to overdrive pacing can be estimated using signals from sites other than the paced site. A cellular automaton model of reentry was developed to validate a formula for estimation of ER using remote sites against the difference between the post-pacing interval (PPI) and tachycardia cycle length determined solely from paced site signals. The model was also used to study resetting of tachycardia phase by single premature paced stimuli, and the general behavior and features of entrained surfaces. From simulation results, ER at the paced site was accurately estimated from >99.8% of 20,764 remote sites during pacing at 24 sites and 3 paced cycle lengths. Modeling of the ER predicts complex perturbations of the activation sequence in the neighborhood of the overdrive pacing site. For single premature stimuli that penetrated the tachycardia circuit, phase reset of the tachycardia was linearly related to distance between the central obstacle and the paced site