Method Comparison and Validation of the Determination of Ejection Duration from Oscillometric Measurements

摘要

The ejection duration (ED) is an important indicator of ventricular function as well as ventriculo-arterial coupling, especially for heart failure with reduced ejection fraction. Thus, the non-invasive oscillometric determination of ED from arterial pressure waves could enhance methods of pulse wave analysis. The aim of this work was to compare different approaches to calculate the ED from oscillometric measurements and to test and to validate the determination of ED with results from measurements using radial tonometry. Oscillometric and tonometric pulse wave measurements were obtained in direct succession from each patient with the Mobil-O-Graph and with the Sphygmocor device in a comparative study. Also, the results from the internal algorithm of SphygmoCor were obtained. Several methods for the determination of ED were implemented and applied to the given measurements. The results of Mobil-O-Graph were compared with the ejection durations from the internal algorithm of SphygmoCor. Several algorithms had a mean error lower than the step size of the recordings. The algorithm using numerical central differences to find the maximum curvature of the curve was chosen for the determination of ED due to its lowest standard deviation compared with others, its low mean error and its stability. The mean difference between Mobil-O-Graph and SphygmoCor was 7 ms (35 SD). An algorithm for determination of ED was selected and tested successfully on radial and brachial recordings. As the differences between locations as well as between algorithms are sufficiently small, the determination of ejection duration from brachial oscillometric pulse waves seems feasible.