A cascade filter for pulse wave baseline drift elimination

Author(s):  
Luo Kan ◽  
Li Jianqing ◽  
Wu Jianfeng ◽  
Xu Gaozhi
2021 ◽  
Author(s):  
Jingdong Yang ◽  
Lei Chen ◽  
Shuchen Cai ◽  
Tianxiao Xie ◽  
Haixia Yan

Abstract H-type hypertension increases the risks of stroke and cardiovascular disease, posing a great threat to human health. Pulse diagnosis in traditional Chinese medicine ( TCM ) combined with deep learning can independently predict suspected H-type hypertension patients by analyzing their pulse physiological activities. However, the traditional time-domain feature extraction has a higher noise and baseline drift, affecting the classification accuracy. In this literature, we propose an effective prediction on frequency-domain pulse wave features. First, we filter time-domain pulse waves via removal of high-frequency noises and baseline shift. Second, Hilbert-Huang Transform is explored to transform time-domain pulse wave into frequency-domain waveform characterized by Mel-frequency cepstral coefficients (MFCC). Finally, an improved BiLSTM model, combined with mixed attention mechanism is built to applied for prediction of H-type hypertension. With 337 clinical cases from Longhua Hospital affiliated to Shanghai University of TCM and Hospital of Integrated Traditional Chinese and Western Medicine, the 3-fold cross-validation results show that sensitivity, specificity, accuracy, F1-score and AUC reaches 93.48%, 95.27%, 97.48%, 90.77% and 0.9676, respectively. The proposed model achieves better generalization performance than the classical traditional models. In addition, we calculate the feature importance both in time-domain and frequency-domain according to purity of nodes in Random Forest and study the correlations between features and classification that has a good reference value for TCM clinical auxiliary diagnosis.


2021 ◽  
Vol 11 (18) ◽  
pp. 8470
Author(s):  
Shuqiang Yang ◽  
Deqiang Cheng ◽  
Jun Wang ◽  
Huafeng Qin ◽  
Yike Liu

Vein recognition technology identifies human vein characteristics under near-infrared light and compares it with stored vein information for personal identification. Although this has high anti-counterfeiting performance, it is possible to fabricate artificial hands that simulate vein characteristics to deceive the identity authentication system. In view of this potential deficiency, we introduced heart rate information to vein authentication, a means of living body detection, which can further improve the anti-counterfeiting effect of vein authentication. A hand vein transillumination imaging experiment was designed to prove its effectiveness. In the proposed method, a near-infrared light source is used to transilluminate the hand, and the transillumination images are collected by a common camera. Then, the region of interest is selected for gray-scale image processing, the feature value of each frame is extracted by superimposing and averaging the images, and then the one-dimensional pulse wave is drawn. Furthermore, the baseline drift phenomenon is filtered by morphological methods, and the maximum percentage frequency is determined by Fast Fourier Transform, that is, the pulse wave frequency. The heart rate value is then calculated, and finally, the stability of the heart rate detection result is evaluated. The experiment shows that the method produces accurate and stable results, demonstrating that it can provide living information (heart rate value) for vein authentication, which has great application prospects and development opportunities in security systems.


VASA ◽  
2014 ◽  
Vol 43 (6) ◽  
pp. 423-432 ◽  
Author(s):  
Qingtao Meng ◽  
Si Wang ◽  
Yong Wang ◽  
Shixi Wan ◽  
Kai Liu ◽  
...  

Background: Orthostatic hypotension (OH) is a disease prevalent among middle-aged men and the elderly. The association between arterial stiffness and OH is unclear. This study evaluates whether arterial stiffness is correlated with OH and tests the usefulness of brachial-ankle pulse wave velocity (baPWV), an arterial stiffness marker, with regard to identifying OH. Patients and methods: A sample of 1,010 participants was recruited from the general population (64.8 ± 7.7 years; 426 men) who attended health check-ups. BaPWV and the radial augmentation index (rAI) were both assessed as the arterial stiffness markers, and OH was determined using blood pressure (BP) measured in the supine position, as well as 30 seconds and 2 minutes after standing. Results: The prevalence of OH in this population was 4.9 %. Compared with the non-OH group, both baPWV (20.5 ± 4.5 vs 17.3 ± 3.7, p < 0.001) and rAI (88.1 ± 10.8 vs 84.2 ± 10.7, p < 0.05) were significantly higher in the OH group. In the multiple logistic regression analysis, baPWV (OR, 1.3; 95 % CI, 1.106–1.528; p < 0.05) remained associated with OH. Moreover, the degree of orthostatic BP reduction was related to arterial stiffness. In addition, increases in arterial stiffness predicted decreases in the degree of heart rate (HR) elevation. Finally, a receiver operating characteristic (ROC) curve analysis showed that baPWV was useful in discriminating OH (AUC, 0.721; p < 0.001), with the cut-off value of 18.58 m/s (sensitivity, 0.714; specificity, 0.686). Conclusions: Arterial stiffness determined via baPWV, rather than rAI, was significantly correlated with the attenuation of the orthostatic hemodynamic response and the resultant OH. The impaired baroreceptor sensitivity might be the mechanism. In addition, baPWV appears to be a relatively sensitive and reliable indicator of OH in routine clinical practice.


VASA ◽  
2015 ◽  
Vol 44 (5) ◽  
pp. 341-348 ◽  
Author(s):  
Marc Husmann ◽  
Vincenzo Jacomella ◽  
Christoph Thalhammer ◽  
Beatrice R. Amann-Vesti

Abstract. Increased arterial stiffness results from reduced elasticity of the arterial wall and is an independent predictor for cardiovascular risk. The gold standard for assessment of arterial stiffness is the carotid-femoral pulse wave velocity. Other parameters such as central aortic pulse pressure and aortic augmentation index are indirect, surrogate markers of arterial stiffness, but provide additional information on the characteristics of wave reflection. Peripheral arterial disease (PAD) is characterised by its association with systolic hypertension, increased arterial stiffness, disturbed wave reflexion and prognosis depending on ankle-brachial pressure index. This review summarises the physiology of pulse wave propagation and reflection and its changes due to aging and atherosclerosis. We discuss different non-invasive assessment techniques and highlight the importance of the understanding of arterial pulse wave analysis for each vascular specialist and primary care physician alike in the context of PAD.


VASA ◽  
2017 ◽  
Vol 46 (2) ◽  
pp. 108-115 ◽  
Author(s):  
Christian Alexander Schaefer ◽  
Anna Katharina Blatzheim ◽  
Sebastian Gorgonius Passon ◽  
Kristin Solveig Pausewang ◽  
Nadjib Schahab ◽  
...  

Abstract. Background: The beneficial effect of statin therapy on the progress of atherosclerotic disease has been demonstrated by numerous studies. Vascular strain imaging is an arising method to evaluate arterial stiffness. Our study examined whether an influence of statin therapy on the vessel wall could be detected by vascular strain imaging. Patients and methods: 88 patients with recently detected atherosclerosis underwent an angiological examination including ankle-brachial index (ABI), pulse wave index (PWI), central puls ewave velocity and duplex ultrasound. Captures for vascular strain analysis were taken in B-mode during ultrasound examination of the common carotid artery and evaluated using a workstation equipped with a speckle tracking based software. A statin therapy was recommended and after six months a follow-up examination took place. Meanwhile, the non-adherence of a group of patients (N = 18) lead to a possibility to observe statin effects on the vascular strain. Results: In the statin non-adherent group the ABI decreased significantly to a still non-pathological level (1.2 ± 0.2 vs. 1.0 ± 0.2; p = 0.016) whereas it stagnated in the adherent group (1.0 ± 0.2 vs. 1.0 ± 0.2; p = 0.383). The PWI did not differ in the non-adherent group (180.5 ± 71.9 vs. 164.4 ± 75.8; p = 0.436) but under statin therapy it decreased significantly (261.8 ± 238.6 vs. 196.4 ± 137.4; p = 0.016). In comparison to the adherent group (4.2 ± 2.0 vs. 4.0 ± 1.8; p = 0.548) under statin therapy the radial strain decreased significantly in the non-adherent group (4.7 ± 2.0 vs. 3.3 ± 1.1; p = 0.014). Conclusions: Our findings reveal a beneficial influence of statin therapy on the arterial wall detected by vascular strain analysis.


Sign in / Sign up

Export Citation Format

Share Document