Embodiments of the invention provide a method and apparatus that allow for a personalised heart tissue model to be generated, that models heart tissue electrophysiology behaviour at a personalised level, based upon activation measurements of an individual subject's heart in response to a number of predefined pacing protocols. The activation measurements are collected using a catheter placed onto the subject's heart, which is then paced via the catheter in accordance with the pacing protocols, and activation times of the heart tissue recorded. The activation measurements are used to generate a personalised tissue model, for example, by parameter matching the activation measurements with a large number of predefined sets of activation measurements, to determine the best-fit set； the best-fit set is then used as a personalised heart tissue model in a two or three-dimensional simulation of heart tissue activation in response to simulated stimulation.
