دانلود رایگان مقاله لاتین افزایش شدت موج کرونر از سایت الزویر
عنوان فارسی مقاله:
آنالیز نیرومندی افزایش شدت موج کرونر توسط تفاضل محدود مرکزی مراتب بالا
عنوان انگلیسی مقاله:
Enhancing coronary Wave Intensity Analysis robustness by high order central finite differences
سال انتشار : 2014
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مقدمه انگلیسی مقاله:
1. Introduction
Two decades following its introduction, Wave Intensity Analysis has become an established technique to examine arterial dynamics.1,2 Improvements in catheters3,4 in the past decades have enabled the application of Wave Intensity Analysis in the coronary arteries,5e8 which is the focus of this paper. The goal of recent investigations was aimed at exploiting the capacity of coronary Wave Intensity Analysis (cWIA) to distinguish between the proximal haemodynamics and the impact of cardiac mechanics on the microcirculation, for clinical translation. More specifically, the Backward Expansion Wave (BEW) has been primarily studied in order to elucidate the link between myocardial relaxation and the sharp diastolic rise of coronary inflow. However, application of WIA to the coronary vessels has been considered with skepticism from some investigators9 mainly due to the lack of evidence that the cWIA-derived indices can have prognostic value. Moreover, the high dependency of the cWIA outcome on the practitioners, mainly due to the unknown dependency on the noise introduced by the acquisition process and the pre-processing filtering step, has been considered a notable weakness. While the first point has been recently addressed since the clinical usefulness of cWIA and the prognostic value of the cWIA derived metrics have been consistently demonstrated,10e12 the second one remains still unknown. This is a major motivation to undertake the current study in order to enhance the robustness of the cWIA outcome. In a recent study Kyriacou et al.10 used cWIA to identify the optimal atrioventricular delay in biventricular pacing in order to improve ventricular contractility and relaxation thereby increasing the cardiac output. Lockie et al.11 found that a cWIA-derived index was central in the commonly seen but poorly understood phenomenon of ‘warm-up’ angina. Most recently, De Silva et al.12 have shown for the first time that a real-time derived BEW peak can predict functional myocardial recovery following myocardial infarction. Given these successes it is becoming increasingly relevant to assess the robustness of cWIA outcomes independently of clinical context through each of the steps involved in the analysis. In general, measured arterial pressure and velocity waveforms contain appreciable levels of noise. In the coronary vessels this situation is further exacerbated by cardiac motion. For this reason, in the literature, pressure and velocity signals are typically ensemble-averaged and subsequently smoothed most often by using the SavitzkyeGolay (SeG) filter.1,5,11e14 This filter is applied because it is believed to preserve the peaks of the waveforms, which are a principal feature in performing a reliable cWIA. However, note that the quantities involved in the cWIA are exclusively the first order time derivatives of the signals, on which the relative impact of smoothing is greater than on the signals themselves. Surprisingly, the influence that the SeG filter parameters have on the signals’ time derivative and in turn on the cWIA profile has not been investigated to date. Furthermore, the values of the filter parameters used in the different studies are almost never included in the publications.1,5,11,12,14 Therefore, the purpose of this paper is firstly to qualitatively and quantitatively characterize the impact that the SeG filter parameters have on the cWIA outcome and the derived clinical metrics. The SeG filter is applied as a differentiator to calculate the signals’ time derivative, input of the cWIA, directly from the ensemble-averaged waveforms. However, there is an alternative approach employed in the literature,5,11 which is to compute the signals’ time derivative after smoothing the ensemble-averaged signals. Due to the lack of a preferred or standardized approach in the literature, we performed the sensitivity analysis for both approaches. In addition, with the purpose of introducing a straightforward standardized parameter-free approach, we propose a new procedure that applies a finite difference scheme to estimate the time derivatives directly from ensemble-averaged data. We then compare the SeG approaches with the proposed procedure in terms of the variability exhibited with respect to the cWIA metrics (Pulse Wave Speed, area and peak of the main waves and the total energy carried by the forward and backward travelling waves).
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کلمات کلیدی:
Wave Intensity Analysis separation into forward travelling waves (top ... https://www.researchgate.net/.../261440271_fig3_Wave-Intensity-Analysis-separation-in... See figure: 'Wave Intensity Analysis separation into forward travelling waves (top)...' from publication 'Enhancing coronary Wave Intensity Analysis robustness by ... Coronary Wave Energy A Novel Predictor of Functional Recovery After ... https://www.researchgate.net/.../235896526_Coronary_Wave_Energy_A_Novel_Predict... Regional left ventricular function and late-gadolinium enhancement were assessed by .... Enhancing coronary Wave Intensity Analysis robustness by high order ... Accurate and Standardised Coronary Wave Intensity Analysis ... https://kclpure.kcl.ac.uk/.../accurate-and-standardised-coronary-wave-intensity-analysi... Aug 3, 2016 - Accurate and Standardised Coronary Wave Intensity Analysis ... Finally, the feasibility (accuracy and robustness) of the method was evaluated. Simone Rivolo - Citazioni di Google Scholar scholar.google.com/citations?user=F4pOPx4AAAAJ&hl=it Researcher, King's College London - kcl.ac.uk In silico coronary wave intensity analysis: application of an integrated ... Enhancing coronary wave intensity analysis robustness by high order central finite ... [PDF]Changes in Non-Invasive Wave Intensity Parameters with Variations of ... www.cinc.org/archives/2016/pdf/300-302.pdf by N Pomella derivatives, upon which wave intensity analysis is based. This study aims to investigate the .... Redwood S. Enhancing coronary Wave Intensity Analysis robustness by high order central finite differences. Artery. Res 2014; 98:109-8(3). Impact of coronary bifurcation morphology on wave propagation ... ajpheart.physiology.org/content/311/4/H855 by S Rivolo - 2016 - Related articles Oct 1, 2016 - The branching pattern of the coronary vasculature is a key ...... Enhancing coronary wave intensity analysis robustness by high order central ...
