The model of topical heart cooling during induced hypothermic cardiac arrest in open heart surgery

Presents a new method of parallel computer simulation in cardiac surgery. The heat equation is transformed to a set of difference equations which are solved numerically by the finite difference method. The authors are considering the level of moderate hypothermia with esophageal temperature of 28/spl deg/C. The average initial heart temperature after cardioplegia is supposed to be 11/spl deg/C. Two types of topical cooling are considered: first, the temperature of the cooling liquid (TCL) is held constant on 0.2/spl deg/C with a heat exchanger, and second, the initial TCL is set to 0.2/spl deg/C and no heat exchanger is used. The heart modelling method is based on a series of axial-slice images obtained by a human heart CT-scan. After definition of different substances the images are digitalised with the requested resolution and compounded into a three dimensional body. Using a parallel computer with 16 high speed processors, the resulting calculation is approximately ten times slower than the real cooling process in nature.