When a child is born with a malformed heart, an accurate understanding of the complex morphology and related surgical strategies is important to paediatric cardiac surgeons. Through our interdisciplinary research with paediatric cardiac surgeons we have developed a surgical simulator for this purpose. The complex morphology of a heart model requires highly detailed geometry, both for visualisation and tissue-deformation. To achieve this goal, combined with real-time interaction, our primary strategy as been to utilise modern consumer graphics processing units (GPUs) since they have a larger number of floating point operations per second than a comparable CPU