Sharif Digital Repository

Acute hypotension episodes are one of the hemodynamic instabilities with high mortality rate that is frequent among many groups of patients. Prediction of acute hypotension episodes can help clinicians to diagnose the cause of this physiological disorder and select proper treatment based on this diagnosis. In this study new physiological time series are generated based on heart rate, systolic blood pressure, diastolic blood pressure and mean blood pressure time series. Statistical features of these time series are extracted and patients whom are exposed to acute hypotension episodes in future 1 hour time interval and whom are not, are classified based on these features and with the aid of... 

Goal: Continuous blood pressure (BP) monitoring can provide invaluable information about individuals' health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This paper presents an efficient algorithm, based on the pulse arrival time (PAT), for the continuous and cuffless estimation of the systolic BP, diastolic blood pressure (DBP), and mean arterial pressure (MAP) values. Methods: The proposed framework estimates the BP values through processing vital signals and extracting two types of features, which are based on either physiological parameters or whole-based representation of vital signals. Finally,... 

Background: The early repolarization pattern (ERP) has been considered a normal variant in electrocardiography (ECG) for a long time. Nevertheless, increasing evidence has demonstrated its association with adverse outcomes. Objectives: The present study aimed to evaluate the prevalence of ERP in the Iranian general population and demonstrate its clinical and ECG correlates. Methods: A cross sectional study, comprising 1424 consecutive healthy adult individuals, was conducted at two university based hospitals in Tehran, Iran in 2012-2013. The ERP prevalence, clinical characteristics and ECG morphology were investigated in volunteers. Results: ERP was present in 136 out of 1,424 people (9.6%).... 

Obstruction of left anterior descending artery (LAD) due to the thrombosis or atherosclerotic plaques is the leading cause of death worldwide. Targeted delivery of drugs through micro- and nanoparticles is a very promising approach for developing new strategies in clot-busting or treating restenosis. In this work, we modelled the blood flow characteristics in a patient-specific reconstructed LAD artery by the fluid–solid interaction method and based on physiological boundary conditions. Next, we provided a Lagrangian description of micro- and nanoparticles dynamics in the blood flow considering their Brownian motion and the particle–particle interactions. Our results state that the number of... 

Biomechanical forces and hemodynamic factors influence the blood flow and the endothelial cells (ECs) morphology. These factors behave differently beyond the coronary artery stenosis. In the present study, unsteady blood flow in the left coronary artery (LCA) and its atherosclerotic bifurcating vessels, left anterior descending (LAD) and left circumflex (LCX) arteries, were numerically simulated to investigate the risk of plaque length development and secondary plaque formation in the post-stenotic areas. Using fluid–structure interaction (FSI) model, compliance of arterial wall and vessel curvature variations due to cardiac motion were considered. The arteries included plaques at the... 

Biomechanical forces and hemodynamic factors influence the blood flow and the endothelial cells (ECs) morphology. These factors behave differently beyond the coronary artery stenosis. In the present study, unsteady blood flow in the left coronary artery (LCA) and its atherosclerotic bifurcating vessels, left anterior descending (LAD) and left circumflex (LCX) arteries, were numerically simulated to investigate the risk of plaque length development and secondary plaque formation in the post-stenotic areas. Using fluid–structure interaction (FSI) model, compliance of arterial wall and vessel curvature variations due to cardiac motion were considered. The arteries included plaques at the... 

Ageing is one of the main contributing factors towards increasing arterial stiffness, leading to changes in peripheral pulses propagation. Therefore the characteristics of the photoplethysmogram (PPG) pulse, especially the rising edge and peak position, are greatly affected. In this study, the PPG pulse rising edge and corresponding peak position have been investigated non-invasively in human subjects as a function of age. Fifteen healthy subjects were selected and grouped in five age intervals, from 20 to 59 years, based on their comparable systolic-diastolic blood pressure and PPG amplitude. As expected, the peripheral pulse shows a steep rise and early peak in younger subjects. With age,... 

Introduction: This study was conducted to investigate the relationship of glomerular and tubular dysfunctions with glycaemic control, lipid, lipoprotein, apolipoproteins and antioxidant status in 72 patients with type 2 diabetes mellitus. Methods: Urine albumin concentration was measured by immunoturbidimetric and urine N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP) activities with colorimetric methods. Glycated haemoglobin was measured using affinity chromatography. Erythrocyte glu ta thione reductase and glutathione peroxidase activities and serum levels of malondialdehyde, lipids, lipoproteins and apolipoproteins were determined in patients with type 2 diabetes...