This paper describes an action research project based on the process of designing the visualisation of heart and breath rate data for the interactive artwork Cardiomorphologies. The project aimed to realise the affective goals of the artist as closely as possible by studying the audience experience of the visualisations and incorporating the findings into an iterative design process. The qualities of richness and ambiguity were found to contribute to the achievement of the artists? two major aims: 1) to create a sense of integrated physical and mental engagement with the work and 2) to create a reflective state in which participants consider correlations between their thoughts and specific physiological states