Lecture

Input impedance: Wave reflections & Fourier analysis

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In course

ME-481: Biomechanics of the cardiovascular system

This lecture will cover anatomy and physiology of the cardiovascular system, biophysics of the blood, cardiac mechanics, hemodynamics and biomechanics of the arterial system, microcirculation and biomechanics of the venous system. ...

Description

This lecture covers the concept of input impedance in the context of wave reflections and Fourier analysis of arterial waves. It explains how wave reflections can be augmented by peripheral occlusion, the relationship between pressure and flow during Valsalva strain, and the breakdown of pressure and flow pulses into their Fourier components. The instructor discusses the definition of input impedance, its presence or absence of reflections, and its modulation by peripheral resistance and compliance. Examples of input impedance in different scenarios, such as a frictionless tube with a fully blocked end, are also presented. Furthermore, the effects of hypertension on input impedance are explored, along with the reconstruction of arterial waves using Fourier analysis.

Instructor

Nikolaos Stergiopoulos

Education MTE, Managing the Technology Enterprise Program (2000), IMD, Lausanne Ph.D. in Biomedical Engineering & Engineering Mechanics (1990) Iowa State University, Ames, Iowa. MS in Biomedical Engineering (1987) Iowa State University, Ames, Iowa. Diploma in Mechanical Engineering (1985) National Technical University of Athens. Professional Activities 2002 - present: Professor and director of LHTC 2010 - present: Founder and director of Rheon Medical SA, Préverenges, Switzerland 2008 - present: Founder and director of Antlia S.A., PSE-C, EPFL campus, Switzerland 1998 - 2007: Founder and Scientific Director of EndoArt S.A., Lausanne, Switzerland 1996 - 2002: Assistant professor at the Biomedical Engineering Laboratory, Swiss Federal Institute of Technology, Lausanne, Switzerland. 1991 - 1996: Research Associate at Swiss Federal Institute of Technology - Lausanne 1990 - 1991: Lecturer, Iowa State University

Official source

Related concepts (32)

Harmonic analysis

Harmonic analysis is a branch of mathematics concerned with investigating the connections between a function and its representation in frequency. The frequency representation is found by using the Fourier transform for functions on the real line, or by Fourier series for periodic functions. Generalizing these transforms to other domains is generally called Fourier analysis, although the term is sometimes used interchangeably with harmonic analysis.

Hypertension

Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. It is, however, a major risk factor for stroke, coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, chronic kidney disease, and dementia. Hypertension is a major cause of premature death worldwide.

Impedance matching

In electronics, impedance matching is the practice of designing or adjusting the input impedance or output impedance of an electrical device for a desired value. Often, the desired value is selected to maximize power transfer or minimize signal reflection. For example, impedance matching typically is used to improve power transfer from a radio transmitter via the interconnecting transmission line to the antenna. Signals on a transmission line will be transmitted without reflections if the transmission line is terminated with a matching impedance.

Fourier analysis

In mathematics, Fourier analysis (ˈfʊrieɪ,_-iər) is the study of the way general functions may be represented or approximated by sums of simpler trigonometric functions. Fourier analysis grew from the study of Fourier series, and is named after Joseph Fourier, who showed that representing a function as a sum of trigonometric functions greatly simplifies the study of heat transfer. The subject of Fourier analysis encompasses a vast spectrum of mathematics.

Fourier transform

In physics and mathematics, the Fourier transform (FT) is a transform that converts a function into a form that describes the frequencies present in the original function. The output of the transform is a complex-valued function of frequency. The term Fourier transform refers to both this complex-valued function and the mathematical operation. When a distinction needs to be made the Fourier transform is sometimes called the frequency domain representation of the original function.

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