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The aim of this study was to quantify short-term maternal-fetal cardiac couplings in early, mid and late gestation fetuses by using the high resolution joint symbolic dynamics (HRJSD) analysis approach. The analysis was based on fetal electrocardiograms (FECGs) of 66 healthy fetuses [22 from 16∼25 weeks (GA1), 22 from 26–30 weeks (GA2) and 22 from 32–41 weeks (GA3)]. Results demonstrate that HRJSD...
Many methods have been proposed for analysing high frequency blood pressure or ECG data. We review a recently proposed new approach for analysing such data based on attractor reconstruction and compare it to heart rate variability that analyses the beat-to-beat intervals. Our new approach uses all the available data and so can detect changes in the shape of the waveform.
The aim of the research is to implement and test a telemedical system to monitor and analyze physiological and movements signals from human. The system incorporates the body central unit (Bluetooth radio, CPU and accelerometer), wearable sensors (ECG, temperature sensor, skin humidity sensor) which are located on the human body, and a mobile computing device to forward data to the remote medical server...
The tachogram is typically constructed by detecting the R peaks in the electrocardiogram (ECG). Sometimes the ECG is however very noisy, which makes it hard to find the R peaks in these cases by using only the ECG. Information from other signals can then be used in order to find the R peaks. In this paper, a method is suggested that is able to automatically detect signals with the same periodic behavior...
Electrogram-guided ablation has been recently developed for allowing better detection and localization of abnormal atrial activity that may be the source of arrhythmogeneity. Nevertheless, no clear indication for the benefit of using electrograms guided ablation over empirical ablation was established thus far, and there is a clear need of improving the localization of cardiac arrhythmogenic targets...
This study aims to understand the effect of variations in cardiac conductivity values on defibrillation thresholds in a simple heart-in-a-bath model. A generalised polynomial chaos approach is used to generate 41 sets of four cardiac conductivity values based on the three commonly used data sets. Simulations, using the bidomain equations, are performed on an isolated heart placed in a bath with a...
Coarctation of the aorta (CoA) is one of the most common congenital heart defects in the United States, and despite treatment, patients have a decrease in life expectancy. Computational fluid dynamics simulations can provide the physician with a non-invasive method to measure the pressure gradient. With HARVEY, a massively parallel hemodynamics application, patient specific simulations can be conducted...
ECGSIM is an interactive open source software package aimed at supporting ECG education and research. In this package, the user can change the local transmembrane potential interactively the resulting ECG changes are simulated and displayed instantaneously. In the previous versions of ECGSIM only a single heartbeat can be simulated, limiting its possibilities in inspecting changes in ECG morphology...
Cardiac fibrillatory dynamics are identified with spiral waves in mathematical modeling of cardiac electrical propagation. Automatic identification of spiral wave dynamics is essential for patient specific cardiac modeling.
The contribution of the ATP-sensitive K+ (KATP+) current to the action potential is an important component of cardiac ischaemia. The purpose of this study was to investigate how the formulation of IK(ATP) influences action potential shape and duration in the Ten Tusscher-Panfilov 2006 model of human ventricular myocytes. We compared four different IK(ATP) formulations, which were inserted in the epicardial...
Cardiopulmonary resuscitation (CPR) artifact filtering techniques have not been successfully combined with commercial shock advice algorithms (SAA) to diagnose the rhythm during CPR. Recently, a promising new approach based on using SAAs especially designed to diagnose the filtered ECG has been introduced. This study evaluates the impact of filtering CPR artifacts on the shock/noshock decision for...
Electromyographic (EMG) noise is constantly present in stress test electrocardiographic recordings, due to physical exercise. The aim of the study is to investigate a filter that suppress sufficiently the EMG noise, with minimal distortion of high frequency content of the QRS complex.
The goal of this study was to compare several ECG signal decomposition methods in order to enhance the accuracy of T wave end localisation. PTB Diagnostic ECG Database comprising 549 recordings was used. The idea was to combine the 8 independent leads (I, II, V1,…, V6) of the standard 12-leads ECG into a single lead.
Increased left ventricular (LV) mass leads to higher sensitivity of heart to ischemic injury. This study was focused on comparison of susceptibility of rabbit hearts with different LV mass to short period of ischemia and its modification in consequence of repetition of short ischemic periods. Although higher count of arrhythmias was observed in hearts with higher LV mass during the first ischemia,...
Cardiovascular diseases (CVD) are the prime causes of human mortality and morbidity worldwide. However, CVD can be prevented or cured, if detected early or on-time, where technology can be of significant help. Tackling the issue of comfort of patient by reducing the number of electrode, by allowing the remote home monitoring, and by allaying the need of physical presence of patient in hospital is...
During cardiopulmonary resuscitation feedback systems can help rescuers to achieve optimal chest compression rates. In this paper we describe and compare two methods to provide chest compression rate feedback based only on the thoracic impedance signal, available in automatic external defibrillators. The first method (time domain) identified the relative maxima of the impedance and characterized each...
Beat-to-beat variability of the maximal amplitudes of thoracic impedance (ΔZmax) and of its first derivative (dZ/dtmax) remain unexplored. We examined the effects of four maneuvers eliciting different sympathetic activity levels on ΔZmax and dZ/dtmax time-frequency spectral measures. Seventeen healthy subjects performed 5-min maneuvers: lying, controlled breathing, standing (S) and exercise (E). Time-frequency...
Application of cardiopulmonary resuscitation to people suffering from cardiac arrest has become an effective way of increasing chances of survival. Current CPR is done manually, however new electro-mechanical resuscitation devices are capable of providing chest compressions at a constant rate and depth, even when the patient is being transported.
The risk stratification of sudden cardiac death after myocardial infarction plays an important role in cardiology. It influences the treatment of a patient and the use of implantable devices. However, the majority of well known methods for stratifying risk still fail to predict sudden cardiac death with high accuracy. The heart rate turbulence delivers good results that could be complemented by studying...
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