AN INNOVATIVE DICROTIC NOTCH DETECTION ALGORITHM WHICH COMBINES RULE-BASED LOGIC WITH DIGITAL SIGNAL-PROCESSING TECHNIQUES

Automated, real-time localization of the dicrotic notch, a component o f the arterial pressure waveform, represents a deceptively complex pro blem in computerized biomedical signal processing. The high-frequency nature of the notch can make it difficult to distinguish from artifact ual noise or from other high-frequency physiological components of the waveform. In addition, the contour of the notch varies with vascular status and with propagation through arterial beds, requiring any detec tion algorithm to recognize various possible notch conformations. Fina lly, location of the notch along the waveform may vary widely dependin g on other hemodynamic variables, further complicating detection algor ithms. We have reviewed various published algorithms and have implemen ted a number of them to determine the strengths and shortcomings of ea ch. We then developed a reliable and accurate hybrid algorithm which u tilizes the strengths of the various algorithmic approaches reviewed; after analyzing the waveform, the algorithm selects the most appropria te method for accurate notch localization based on a series of wavefor m features. The application of rule-based logic represents a relativel y unique approach to digital signal processing. (C) 1995 Academic Pres s, Inc.