BACKGROUND: Static cold storage is a mainstay of the heart transplantation (HTx) process. However, the temperature distribution within the organ at each stage of HTx is unknown. In this study, we aimed to quantify how long it took for the heart to warm up and cool down and the nature of temperature distribution with the organ at each stage of HTx. METHODS: We used high-fidelity computational time-varying biothermal modeling on an anatomical human heart model to model the HTx process in 5 interdependent stages, including cardioplegia, back-table preparation, static cold storage ice box storage and transport, back-table preparation at the recipient institution and warm-up within the recipient body before cross-clamp release. RESULTS: Results indicate that the heart experiences roller-coaster-like temperature changes in stage, including rapid cool down from body temperature to <
10 °C within 15 min in stage 1 with a maximum cooling rate of 5 °C/min. This was followed by cooling and extended duration of temperatures <
2 °C in the ice box and rapid warming up to body temperature within 10 min at rates of 2 °C/min and 4 °C/min for the left and right sides, respectively, during implantation. Temperature distribution throughout the heart was heterogeneous, with right-sided temperature change occurring nearly 2× faster than on the left side. CONCLUSIONS: We present, for the first time, detailed temperature distributions and evolution at each stage of HTx. Quantification of the rapid and heterogeneous temperature changes is crucial to optimize HTx and improve organ viability.