A novel method to quantify arterial pulse waveform morphology: attractor reconstruction for physiologists and clinicians

Nandi, Manasi; Venton, Jenny; Aston, Philip J.

doi:10.1088/1361-6579/aae46a

Cited by 28 publications

(31 citation statements)

References 32 publications

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“…Our SPAR method uses all of the available waveform data and repackages it in the form of a two-dimensional attractor, using Takens' delay coordinates together with some additional steps, and so the waveform shape is encoded in the shape of the attractor (see Fig. 1) [2,3]. Clearly, any changes in the shape of the waveform will result in corresponding changes in the morphology of the attractor.…”

Section: The Symmetric Projection Attractor Reconstruction Methodsmentioning

confidence: 99%

“…We have previously applied the novel Symmetric Projection Attractor Reconstruction (SPAR) method [2,3] to this mouse data [4], which involved generating an attractor from the ECG signals from which features were manually extracted and machine learning was then used to classify the signals as being from either a wild-type or mutant mouse. In this work, we use deep learning applied to the attractor images directly in order to perform the same classification task.…”

Section: Introductionmentioning

confidence: 99%

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Deep Learning Applied to Attractor Images Derived from ECG Signals for Detection of Genetic Mutation

Aston¹,

Lyle²,

Bonet-Luz³

et al. 2019

2019 Computing in Cardiology Conference (CinC)

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The aim of this work is to distinguish between wild-type mice and Scn5a +/− mutant mice using short ECG signals. This mutation results in impaired cardiac sodium channel function and is associated with increased ventricular arrhythmogenic risk which can result in sudden cardiac death. Lead I and Lead II ECG signals from wild-type and Scn5a +/− mice are used and the mice are also grouped as female/male and young/old.We use our novel Symmetric Projection Attractor Reconstruction (SPAR) method to generate an attractor from the ECG signal using all of the available waveform data. We have previously manually extracted a variety of quantitative measures from the attractor and used machine learning to classify each animal as either wild-type or mutant. In this work, we take the attractor images and use these as input to a deep learning algorithm in order to perform the same classification. As there is only data available from 42 mice, we use a transfer learning approach in which a network that has been pretrained on millions of images is used as a starting point and the last few layers are changed in order to fine tune the network for the attractor images.The results for the transfer learning approach are not as good as for the manual features, which is not too surprising as the networks have not been trained on attractor images. However, this approach shows the potential for using deep learning for classification of attractor images.

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Section: The Symmetric Projection Attractor Reconstruction Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deep Learning Applied to Attractor Images Derived from ECG Signals for Detection of Genetic Mutation

Aston¹,

Lyle²,

Bonet-Luz³

et al. 2019

2019 Computing in Cardiology Conference (CinC)

Self Cite

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“…We have developed a mathematical method [symmetric projection attractor reconstruction (SPAR)] to quantify such changes by using the raw numerical waveform data and minimizing any assumptions made about the signal (Aston, Christie, Huang, & Nandi, 2018;Christie et al, 2015;Nandi et al, 2018). The only assumption is that the waveform is cyclic in nature, and the method can therefore be applied both to controlled, regularly repeating periodic waves (standardized laboratory setting) and to more chaotic waves (unrestrained animals and community/hospital setting).…”

Section: A New Way Of Studying Cardiovascular Waveformsmentioning

confidence: 99%

“…Symmetric projection attractor reconstruction is based on two related mathematical methods (Lorenz, 1963;Takens, 1981), with an additional important step (Aston et al, 2018). We have summarized the key steps in Table 1 and Figure 1, but a more detailed explanation of the method, aimed at a non-mathematical audience, is available and contains a link to a video explanation that might assist with understanding (Nandi et al, 2018).…”

Section: A New Way Of Studying Cardiovascular Waveformsmentioning

confidence: 99%

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Extracting new information from old waveforms: Symmetric projection attractor reconstruction: Where maths meets medicine

Nandi

Aston

2020

Experimental Physiology

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New Findings What is the topic of this review?Symmetric Projection Attractor Reconstruction (SPAR) is a relatively new mathematical method that can extract additional information pertaining to the morphology and variability of physiological waveforms, such as arterial pulse pressure. Herein, we describe the potential utility of the method for more sensitive quantification of cardiovascular changes. What advances does it highlight?We use a simple example of a human tilt table to illustrate these concepts. SPAR can be used on any approximately periodic waveform and may add value to experimental and clinical settings, where such signals are collected routinely. Abstract Periodic physiological waveform data, such as blood pressure, pulse oximetry and ECG, are routinely sampled between 100 and 1000 Hz in preclinical research and in the clinical setting from a wide variety of implantable, bedside and wearable monitoring devices. Despite the underlying numerical waveform data being captured at such high fidelity, conventional analysis tends to reside in reporting only averages of minimum, maximum, amplitude and rate, as single point averages. Although these averages are undoubtedly of value, simplification of the data in this way means that most of the available numerical data are discarded. In turn, this may lead to subtle physiological changes being missed when investigating the cardiovascular system over time. We have developed a mathematical method (symmetric projection attractor reconstruction) that uses all the numerical data, replotting and revisualizing them in a manner that allows unique quantification of multiple changes in waveform morphology and variability. We propose that the additional quantification of these features will allow the complex behaviour of the cardiovascular system to be mapped more sensitively in different physiological and pathophysiological settings.

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Use of a rat model to characterize 35 arterial pulse wave parameters in a comparative study of isoflurane and Zoletil/xylazine anesthesia and the effect of Acanthopanax senticosus extract

Misak,

Grman,

Tomasova

et al. 2023

Anim Models and Exp Med

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BackgroundInformation obtained from arterial pulse waveforms (APW) can be useful for characterizing the cardiovascular system. To achieve this, it is necessary to know the detailed characteristics of APWs in different states of an organism, which would allow APW parameters (APW‐Ps) to be assigned to particular (patho)physiological conditions. Therefore, our work aimed to characterize 35 APW‐Ps in rats under the influence of isoflurane (ISO) and Zoletil/xylazine (ZO/XY) anesthesia and to study the effect of root extract from Acanthopanax senticosus (ASRE) in these anesthetic conditions.MethodsThe right jugular vein of anesthetized rats was cannulated for the administration of ASRE and the left carotid artery for the detection of APWs from which 35 APW‐Ps were evaluated.ResultsWe obtained data on 35 APW‐Ps, which significantly depended on the anesthesia, and thus, they characterized the cardiovascular system under these two conditions. ASRE transiently modulated all 35 APW‐Ps, including a transient decrease in systolic and diastolic blood pressure (BP) and heart rate or increases in pulse BP, dP/dtmax, and systolic and diastolic areas. Whereas the transient effects of ASRE were similar, the extract had prolonged disturbing effects on the cardiovascular system in rats under ZO/XY but not under ISO anesthesia. This negative effect can result from the disturbance caused by ZO/XY anesthesia on the cardiovascular system.ConclusionsWe characterized 35 APW‐Ps of rats under ISO and ZO/XY anesthesia and found that ASRE contains compounds that can modulate the properties of the cardiovascular system, which significantly depended on the status of the cardiovascular system. This should be considered when using ASRE as a nutritional supplement by individuals with cardiovascular problems.

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A novel method to quantify arterial pulse waveform morphology: attractor reconstruction for physiologists and clinicians

Cited by 28 publications

References 32 publications

Deep Learning Applied to Attractor Images Derived from ECG Signals for Detection of Genetic Mutation

Deep Learning Applied to Attractor Images Derived from ECG Signals for Detection of Genetic Mutation

Extracting new information from old waveforms: Symmetric projection attractor reconstruction: Where maths meets medicine

Use of a rat model to characterize 35 arterial pulse wave parameters in a comparative study of isoflurane and Zoletil/xylazine anesthesia and the effect of Acanthopanax senticosus extract

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