Contour Analysis of a Mechanism with Two Dyads

2021 ◽  
pp. 101-122
Author(s):  
Dan B. Marghitu ◽  
Hamid Ghaednia ◽  
Jing Zhao
Keyword(s):  
2012 ◽  
Vol 8 (2) ◽  
pp. 128
Author(s):  
Ali Vazir ◽  
Martin R Cowie ◽  
◽  

Acute heart failure – the rapid onset of, or change in, signs and/or symptoms of heart failure requiring urgent treatment – is a serious clinical syndrome, associated with high mortality and healthcare costs. History, physical examination and early 2D and Doppler echocardiography are crucial to the proper assessment of patients, and will help determine the appropriate monitoring and management strategy. Most patients are elderly and have considerable co-morbidity. Clinical assessment is key to monitoring progress, but a number of clinical techniques – including simple Doppler and echocardiographic tools, pulse contour analysis and impedance cardiography – can help assess the response to therapy. A pulmonary artery catheter is not a routine monitoring tool, but can be very useful in patients with complex physiology, in those who fail to respond to therapy as would be anticipated, or in those being considered for mechanical intervention. As yet, the serial measurement of plasma natriuretic peptides is of limited value, but it does have a role in diagnosis and prognostication. Increasingly, the remote monitoring of physiological variables by completely implanted devices is possible, but the place of such technology in clinical practice is yet to be clearly established.


2015 ◽  
Vol 27 (03) ◽  
pp. 1550021
Author(s):  
S. Mohanalakshmi ◽  
A. Sivasubramanian

Arterial stiffness, resulting in loss of the elastic properties of arteries walls, is an indicator of cardiovascular risk, though the presence of disease is not clinically evident. Augmentation index is an important biomarker of arterial stiffness by which the cardiac risk of the patient can be diagnosed. The current paper outlines the non-invasive assessment of arterial stiffness by analyzing the morphology or contour of PhotoPlethysmoGraph (PPG) signal. PPG pulse was optically acquired with the developed photometric measurement device and the desired features were extracted to determine PPG augmentation Index (PAI) through advanced signal processing implemented in MATLAB. PAI was quantified by the fourth derivative of the signal by enhancing the location of inflection point (augmentation point) after conditioning the signal by efficient pre-processing and filtering techniques. The results reveal that the statistical distribution of PAI for healthy subjects presents a very low value and a very tight distribution. On the contrary, patients have a higher value of PAI and a wide asymmetrical shape of distribution. This work also establishes the usefulness of PPG contour analysis in the investigation of changes in the elastic properties of the vascular system. In conclusion, PAI has revealed to be a non-invasive indicator for arterial stiffness assessments.


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