Assessing cardiovascular dynamics during ventricular assistance.Use of fuzzy clustering techniques

The authors' group has recently developed an expert system realized by means of fuzzy logic algorithms for monitoring and malfunction diagnosis of the left ventricular assist device (LVAD), one of the many types of artificial hearts developed today. The system is named TOTOMES (Tohoku University and Toyohashi University of Technology, monitoring and estimation system). TOTOMES is suitable for clinical application because it operates in an online and realtime fashion on a widely used personal computer in Japan. This article introduces the structure and function of the TOTOMES and explains its techniques, such as multi-interrupt tasks and dynamic system identification; as well as fuzzy reasoning used for realizing state estimation, detection, and diagnosis of malfunctions; and monitoring for cardiovascular dynamics under ventricular assistance and the LVAD drive system