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    Two statistical methods for resolving healthy individuals and those with congestive heart failure based on extended self-similarity and a recursive method

    , Article Journal of Biological Physics ; Volume 32, Issue 6 , 2006 , Pages 489-495 ; 00920606 (ISSN) Atyabi, F ; Livari, M. A ; Kaviani, K ; Rahimi Tabar , M. R ; Sharif University of Technology
    In this paper we introduce two methods for measuring irregularities in human heartbeat time series (HHTS). First we consider the multi-fractal structure of HHTS to distinguish healthy individuals and from those with congestive heart failure. In this way we modify the Extended Self-Similarity (ESS) method and apply it to HHTS. Our second approach is based on the recursive method, which we use to predict the duration of the next heartbeat by considering a few previous ones. We use standard physiological data and show that these approaches lead to very satisfactory methods to resolve the healthy and CHF individuals. These methods can be used potentially in portable electronic heart alarm... 

    Regeneration of stochastic processes: An inverse method

    , Article European Physical Journal B ; Volume 47, Issue 3 , 2005 , Pages 411-415 ; 14346028 (ISSN) Ghasemi, F ; Peinke, J ; Sahimi, M ; Rahimi Tabar, M. R ; Sharif University of Technology
    We propose a novel inverse method that utilizes a set of data to construct a simple equation that governs the stochastic process for which the data have been measured, hence enabling us to reconstruct the stochastic process. As an example, we analyze the stochasticity in the beat-to-beat fluctuations in the heart rates of healthy subjects as well as those with congestive heart failure. The inverse method provides a novel technique for distinguishing the two classes of subjects in terms of a drift and a diffusion coefficients which behave completely differently for the two classes of subjects, hence potentially providing a novel diagnostic tool for distinguishing healthy subjects from those... 

    Functional Modeling of Normal and CHF Heart and Control of Total Artificial Heart- An Optimizing Approach

    , Ph.D. Dissertation Sharif University of Technology Ravanshadi, Samin (Author) ; Jahed, Mehran (Supervisor)
    World-wide, Congestive Heart Failure (CHF) takes hundreds of thousands of lives each year. This chronic heart disease causes poor performance of the heart and insufficient blood pumping to the organs. A significant percentage of patients with CHF require heart transplants for their survival. The high cost of heart transplant, shortage of donor hearts and possibility of its rejection by recipients are serious problems of this type of treatment. Therefore a large number of heart patients are potential beneficiaries of artificial blood pumps such as Ventricular Assist Device (VAD) and Total Artificial Heart (TAH). Performance of these systems must be compliant and complementary to the existing... 

    Modeling and Intelligent Control of Heart Assist Device

    , M.Sc. Thesis Sharif University of Technology Takhtechian, Parisa (Author) ; Jahed, Mehran (Supervisor)
    Congestive heart Failure (CHF) which occurs when the heart is no longer able to pump the blood sufficiently is a worldwide growing health concern. In the U.S. alone, an estimated 8 million people will be diagnosed with heart failure by 2030.Cardiac transplantation with limitations in donor availability, cannot solely resolve this global health concern. Therefore many patients must use alternative remedies, namely Artificial Heart and Ventricle Assist Device (VAD). The Left Ventricular Assist Device (LVAD) is a mechanical pump that is implanted in patients with congestive heart failure to help the left ventricle in pumping blood to the circulatory system. They are known to... 

    Permutation entropy and detrend fluctuation analysis for the natural complexity of cardiac heart interbeat signals

    , Article Physica A: Statistical Mechanics and its Applications ; Volume 392, Issue 14 , 2013 , Pages 3106-3112 ; 03784371 (ISSN) Taherkhani, F ; Rahmani, M ; Taherkhani, F ; Akbarzadeh, H ; Abroshan, H ; Sharif University of Technology
    We compute fractal dimension and permutation entropy for healthy and people who have experienced heart failure. Our result shows that permutation entropy is a suitable approach as well as detrend fluctuation analysis (DFA). The result of DFA shows that the fractal dimensions for healthy and heart failure are different as well as the permutation entropy result. The fluctuation value for permutation entropy for an individual who has experienced heart failure is bigger than for a healthy person. There is some specific change in the interbeat signal of a person who has experienced heart failure, but there is not previous trend for a healthy person  

    A novel distributed model of the heart under normal and congestive heart failure conditions

    , Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 227, Issue 4 , 2013 , Pages 362-372 ; 09544119 (ISSN) Ravanshadi, S ; Jahed, M ; Sharif University of Technology
    Conventional models of cardiovascular system frequently lack required detail and focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the cardiovascular system. It utilizes noninvasive blood flow and pressure seed data and temporal cardiac muscle regional activity to predict the operation of the heart under normal and congestive heart failure conditions. The analysis considers specific regions of the heart, namely, base, mid and apex of left ventricle. The proposed method of parameter estimation for hydraulic electric analogy model is recursive least squares algorithm. Based on simulation results and comparison... 

    Analysis of non-stationary data for heart-rate fluctuations in terms of drift and diffusion coefficients

    , Article Journal of Biological Physics ; Volume 32, Issue 2 , 2006 , Pages 117-128 ; 00920606 (ISSN) Ghasemi, F ; Sahimi, M ; Peinke, J ; Rahimi Tabar, M. R ; Sharif University of Technology
    We describe a method for analyzing the stochasticity in non-stationary data for the beat-to-beat fluctuations in the heart rates of healthy subjects, as well as those with congestive heart failure. The method analyzes the return time series of the data as a Markov process, and computes the Markov time scale, i.e., the time scale over which the data are a Markov process. We also construct an effective stochastic continuum equation for the return series. We show that the drift and diffusion coefficients, as well as the amplitude of the return time series for healthy subjects are distinct from those with CHF. Thus, the method may potentially provide a diagnostic tool for distinguishing healthy... 

    Design and Simulation of Bioimpedance Chip for Monitoring Heart Failure

    , M.Sc. Thesis Sharif University of Technology Rezapour, Mojtaba (Author) ; Sharifkhani, Mohammad (Supervisor)
    Cardiovascular disease is one of the leading causes of death and mortality. among these diseases, heart muscle inability, especially acute decompensated heart failure is very common. There are several methods to diagnose and monitor this disease, but a method that is accurate, non-invasive, portable and easy to access and easy to measure without multiple visits to the clinic; Priority for use. Early detection and continuous monitoring of fluid status by measuring the bio-impedance (Bio-Z) measurement of thoracic magnitude or phase is critical in reducing the mortality of chronic heart failure (CHF) patients. In this dissertation, for monitoring chronic heart failure, bio-impedance chips with... 

    Clinical validation of a smartphone-based handheld ECG device: A validation study

    , Article Critical Pathways in Cardiology ; Volume 21, Issue 4 , 2022 , Pages 165-171 ; 1535282X (ISSN) Ahmadi-Renani, S ; Gharebaghi, M ; Kamalian, E ; Hajghassem, H ; Ghanbari, A ; Karimi, A ; Mansoury, B ; Dayari, M. S ; Khatmi Nemati, M ; Karimi, A ; Zarghami, M. H ; Vasheghani Farahani, A ; Sharif University of Technology
    Lippincott Williams and Wilkins  2022
    Background: Remote cardiac monitoring and screening have already become an integral telemedicine component. The wide usage of several different wireless electrocardiography (ECG) devices warrants a validation study on their accuracy and reliability. Methods: Totally, 300 inpatients with the Nabz Hooshmand-1 handheld ECG device and the GE MAC 1200 ECG system (as the reference) were studied to check the accuracy of the devices in 1 and 6-limb lead performance. Simultaneous 10-second resting ECGs were assessed for the most common ECG parameters in lead I. Afterward, 6-lead ECGs (limb leads), were performed immediately and studied for their morphologies. Results: Of the 300 patients, 297 had...