Abstract 355: Calculating Pulse Wave Velocity from a Single Pressure Waveform Using the Intrinsic Frequency Method

Abstract

INTRODUCTION: Increased aortic stiffness is correlated with many clinically adverse cardiovascular outcomes. The “gold standard” quantitative index for arterial stiffness is the pulse wave velocity (PWV). We have developed a new method called the Intrinsic Frequency ( IF ), which views the arterial pressure waveform as a piecewise combination of two coupled systems, the heart and arterial system which are decoupled upon closure of the aortic valve. Each of these dynamical systems has an inherent frequency of operation (ω 1 and ω 2 ) which gives information about LV function (ω 1 ) as well as arterial dynamics (ω 2 ). METHODS: IF methodology is based on Sparse Time-Frequency Representation method. It uses an effective L 2 -minimization to extract the second intrinsic frequency (ω 2 ) from an aortic pressure waveform. To examine the clinical relevance of this method, IF was applied to aortic pressure waveforms taken from published works. These aortic waveforms were selected from a healthy population free of any cardiovascular diseases (CVD). RESULTS: Our results show that ω 2 represents information about the arterial system and that these measurements are highly correlated with PWV ( r=0.9 ). CONCLUSION: These results show ω 2 can potentially be used to evaluate aortic rigidity and calculate aortic PWV from one pressure waveform. Increased aortic rigidity is a common feature in normal aging and is accelerated in many CVDs including diabetes. One unique advantage of the method is that only a single measurement of the pressure waveform is required to extract the result. Therefore, ω 2 may be employed as a clinically effective noninvasive assessment of cardiovascular health.