Application of multiparametric cardiac measurement system in ejection fraction calculation

Ejection fraction (EF) is the most used parameter for characterisation of Heart Failure (HF) condition. EF is commonly calculated using echocardiography, which is an expensive non–invasive method and not used in primary healthcare. Systolic time intervals (STI) represent a non-invasive and inexpensive method for determination of EF[1, 2]. Heart failure (HF) is the single most expensive diagnosis in medicine. 2–3% of adult population in developed countries have HF diagnosis. It is not detectable by ECG test and it is commonly detected in a late stage, when the process is irreversible [2-5]. In this paper, a multiparametric cardiac measurement system for determination of STI is presented. Measurement system consists of sensors for simultaneous acquisition of electrocardiographic (ECG), phonocardiographic (PCG), photopletysmographic (PPG) and cardiovascular (CV) pulsation signals. CV pulsation signals are measured by long period grating (LPG) fiber-optic sensors[6]. Two non-invasive methods for measuring systolic time intervals (STI) were applied on a set of 6 healthy volunteers, based on ECG, PCG and CV pulsation signals. CV pulsation signals were measured on carotide arthery with PPG and LPG sensors. In the first method, EF was calculated from the obtained STI signals, using CV carotide pulsations measured with the PPG sensor, giving EF values in the range from 0.60 to 0.68, with maximal standard deviation of 0.05. In the second method, EF was obtained using CV carotide pulsations measured with LPG sensor, giving EF values in the range from 0.60 to 0.66, with maximal standard deviation 0.06. Calculated values of EF with both methods were in the 0.55 to 0.75 range which corresponds to normal EF range in healthy individuals

A morphology-preserving algorithm for denoising of EMG-contaminated ECG signals

Goal: Clinical interpretation of an electrocardiogram (ECG) can be detrimentally affected by noise. Removal of the electromyographic (EMG) noise is particularly challenging due to its spectral overlap with the QRS complex. The existing EMG-denoising algorithms often distort signal morphology, thus obscuring diagnostically relevant information. Methods: Here, a new iterative regeneration method (IRM) for efficient EMG-noise suppression is proposed. The main hypothesis is that the temporary removal of the dominant ECG components enables extraction of the noise with the minimum alteration to the signal. The method is validated on SimEMG database of simultaneously recorded reference and noisy signals, MIT-BIH arrhythmia database and synthesized ECG signals, both with the noise from MIT Noise Stress Test Database. Results: IRM denoising and morphology-preserving performance is superior to the wavelet- and FIR-based benchmark methods. Conclusions : IRM is reliable, computationally non-intensive, fast and applicable to any number of ECG channels recorded by mobile or standard ECG devices

Application of multiparametric cardiac measurement system in ejection fraction calculation

Ejection fraction (EF) is the most used parameter for characterisation of Heart Failure (HF) condition. EF is commonly calculated using echocardiography, which is an expensive non–invasive method and not used in primary healthcare. Systolic time intervals (STI) represent a non-invasive and inexpensive method for determination of EF[1, 2]. Heart failure (HF) is the single most expensive diagnosis in medicine. 2–3% of adult population in developed countries have HF diagnosis. It is not detectable by ECG test and it is commonly detected in a late stage, when the process is irreversible [2-5]. In this paper, a multiparametric cardiac measurement system for determination of STI is presented. Measurement system consists of sensors for simultaneous acquisition of electrocardiographic (ECG), phonocardiographic (PCG), photopletysmographic (PPG) and cardiovascular (CV) pulsation signals. CV pulsation signals are measured by long period grating (LPG) fiber-optic sensors[6]. Two non-invasive methods for measuring systolic time intervals (STI) were applied on a set of 6 healthy volunteers, based on ECG, PCG and CV pulsation signals. CV pulsation signals were measured on carotide arthery with PPG and LPG sensors. In the first method, EF was calculated from the obtained STI signals, using CV carotide pulsations measured with the PPG sensor, giving EF values in the range from 0.60 to 0.68, with maximal standard deviation of 0.05. In the second method, EF was obtained using CV carotide pulsations measured with LPG sensor, giving EF values in the range from 0.60 to 0.66, with maximal standard deviation 0.06. Calculated values of EF with both methods were in the 0.55 to 0.75 range which corresponds to normal EF range in healthy individuals

Application of multiparametric cardiac measurement system in ejection fraction calculation

Ejection fraction (EF) is the most used parameter for characterisation of Heart Failure (HF) condition. EF is commonly calculated using echocardiography, which is an expensive non–invasive method and not used in primary healthcare. Systolic time intervals (STI) represent a non-invasive and inexpensive method for determination of EF[1, 2]. Heart failure (HF) is the single most expensive diagnosis in medicine. 2–3% of adult population in developed countries have HF diagnosis. It is not detectable by ECG test and it is commonly detected in a late stage, when the process is irreversible [2-5]. In this paper, a multiparametric cardiac measurement system for determination of STI is presented. Measurement system consists of sensors for simultaneous acquisition of electrocardiographic (ECG), phonocardiographic (PCG), photopletysmographic (PPG) and cardiovascular (CV) pulsation signals. CV pulsation signals are measured by long period grating (LPG) fiber-optic sensors[6]. Two non-invasive methods for measuring systolic time intervals (STI) were applied on a set of 6 healthy volunteers, based on ECG, PCG and CV pulsation signals. CV pulsation signals were measured on carotide arthery with PPG and LPG sensors. In the first method, EF was calculated from the obtained STI signals, using CV carotide pulsations measured with the PPG sensor, giving EF values in the range from 0.60 to 0.68, with maximal standard deviation of 0.05. In the second method, EF was obtained using CV carotide pulsations measured with LPG sensor, giving EF values in the range from 0.60 to 0.66, with maximal standard deviation 0.06. Calculated values of EF with both methods were in the 0.55 to 0.75 range which corresponds to normal EF range in healthy individuals

Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration

Background Early coronary occlusion detection by portable personal device with limited number of electrocardiographic (ECG) leads might shorten symptom-to-balloon time in acute coronary syndromes. Objectives The purpose of this study was to compare the accuracy of coronary occlusion detection using vectorcardgiographic analysis of a near-orthogonal 3-lead ECG configuration suitable for credit card-size personal device integration with automated and human 12 lead ECG interpretation. Methods The 12-lead ECGs with 3 additional leads (“abc”) using 2 arm and 2 left parasternal electrodes were recorded in 66 patients undergoing percutaneous coronary intervention prior to (“baseline”, n = 66), immediately before (“preinflation”, n = 66), and after 90-second balloon coronary occlusion (“inflation”, n = 120). Performance of computer-measured ST-segment shift on vectorcardgiographic loops constructed from “abc” and 12 leads, standard 12-lead ECG, and consensus human interpretation in coronary occlusion detection were compared in “comparative” and “spot” modes (with/without reference to “baseline”) using areas under ROC curves (AUC), reliability, and sensitivity/specificity analysis. Results Comparative “abc”-derived ST-segment shift was similar to two 12-lead methods (vector/traditional) in detecting balloon coronary occlusion (AUC = 0.95, 0.96, and 0.97, respectively, P = NS). Spot “abc” and 12-lead measurements (AUC = 0.72, 0.77, 0.68, respectively, P = NS) demonstrated poorer performance (P < 0.01 vs comparative measurements). Reliability analysis demonstrated comparative automated measurements in “good” agreement with reference (preinflation/inflation), while comparative human interpretation was in “moderate” range. Spot automated and human reading showed “poor” agreement. Conclusions Vectorcardiographic ST-segment analysis using baseline comparison of 3-lead ECG system suitable for credit card-size personal device integration is similar to established 12-lead ECG methods in detecting balloon coronary occlusion

A database of simultaneously recorded ECG signals with and without EMG noise

Goal: Noise on recorded electrocardiographic (ECG) signals may affect their clinical interpretation. Electromyographic (EMG) noise spectrally coincides with the QRS complex, which makes its removal particularly challenging. The problem of evaluating the noise-removal techniques has commonly been approached by algorithm testing on the contaminated ECG signals constructed ad hoc as an additive mixture of a noise-free ECG signal and noise. Consequently, there is an absence of a unique/standard database for testing and comparing different denoising methods. We present a SimEMG database recorded by a novel acquisition method that allows for direct recording of the genuine EMG-noise-free and -contaminated ECG signals. The database is available as open source

A long-period fibre grating sensor for respiratory monitoring

In the current clinical practice of non-invasive mechanical ventilation (NIV), continuous monitoring of respiratory volumes is based on the measurement of air flow through an oronasal mask or mouthpiece. Errors in respiratory-volumes monitoring and patientventilator asynchrony due to the inevitable air leaks from the mask may lead to insufficient ventilation and/or damage of the airway system. Therefore, clinician’s observations of the chest wall expansions are required, but they are subjective, time consuming and strongly dependent on clinician’s experience [1]. We present and validate a method for the measurement of respiratory volumes by a single long period fibre-grating (LPG) sensor of bending. This method is grounded on the hypothesis that the volume of the inhaled air can be correlated with the change in a local torso curvature in a ribs area with stiff underlying tissues. Here, we explain the working principle of the LPG sensors, a monochromatic interrogation scheme, a two-step calibration-test measurement procedure and present results that establish a linear correlation between the change in the local rib-cage curvature and the change in the lung volume. Results also show good sensor accuracy in measurements of tidal and minute respiratory volumes for all clinically relevant breathing volumes [2]. Additionally, we examine the possibility of using the rib-cage movement signal measured by a single LPG sensor as a new way to provide a trigger to the ventilator. Our preliminary results on healthy volunteers provide the statistical evidence of the 200 ms lag of the pneumotechometer with respect to the fibre-optic signal. The proposed single-sensor method is non-invasive, simple, low-cost and easy to implement. Moreover this method does not suffer from the flaws of air-flow measurements, it eliminates the need for chest movement observation by clinicians and can be implemented on both male and female patients. The preliminary results are promising and indicate that the method proposed here could be used in NIV.V International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 and the Second international workshop "Control of light and matter waves propagation and localization in photonic lattices" : PHOTONICA2015 : book of abstracts; August 24-28, 2015; Belgrad

Signal Quality in Reconstructed 12-Lead Ambulatory ECGs Recorded Using 3-Lead Device

Acute myocardial infraction (AMI) is a leading cause of death in the developed countries. Survival of patients having acute coronary syndrome (ACS) dramatically depends on treatment delay. Hence, a technology that would enable ECG recording immediately after ACS symptom occurrence may significantly decrease AMI mortality. In this study we investigate the signal quality of reconstructed 12-lead ECGs by using 3-lead handheld device with dry electrode in realistic ambulatory conditions. For each subject enrolled in the study an individual transformation matrix was calculated during the calibration procedure, and used for 12-lead reconstruction whenever that subject sends a recording from a handheld device. To evaluate fidelity of 12-lead reconstructions, 3 performance metrics were defined. The results show that the reconstruction error is largest on QRS complex and smallest on ST segment for all 3 metrics. This indicates that the reconstruction of the ST segment, which carries the most important information for ischemia detection, is reconstructed with the highest quality. © 2019 IEEE.Conference of 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019 ; Conference Date: 23 July 2019 Through 27 July 2019; Conference Code:15254

Surface ionization study of the hypervalent Li2F molecule

The surface ionization method offers the possibility of measuring ionization energies of atoms, inorganic and organic molecules and clusters, In this study we report the results of the surface ionization of Li2F molecules on a rhenium surface, This work is an attempt to investigate the applicability of the surface ionization technique for the measurment of the ionization energies of hypervalent molelcules at high temperature, There are currently no reliable experimental data for the ionization energy of the Li2F molecule, This molecule has been chosen because previous theoretical calculations have shown that Li2F is a hypervalent (hyperlithiated) molecule with a low ionization energy, The ionization energy was determined to be 5.42+/-0.04 eV

Optical fiber grating sensors for the measurement of superficial temporal artery pulsations

The measurement of arterial blood pressure waveform can provide important data about arterial health, from which general cardiovascular health can be estimated. The arterial blood pressure wave is created by heart contraction which then propagates along the arterial tree. Along its path, the pressure wave causes the distention of arterial walls which consequently can be palpated and measured as micro-movements on the surface of the body. The most frequently used places on the body for recording of the blood pressure waveform are in the fingers and above the radial artery on the wrist. However, since waveforms recorded on the periphery of the body alter from central ones, there is the necessity for non-invasive measurements closer to the ascending aorta [1]. The purpose of this study was to evaluate the possibility of utilizing the superficial temporal artery (STA) as a potential candidate for obtaining arterial waveform recorded non-invasively by fiber grating sensors. The STA is a terminal branch of the external carotid artery and it represents the major artery of the head. The sites over the main branch (near the ear) and the frontal branch of the STA (near ocular area) are easily accessible ones with negligible amounts of fat and muscle tissues. Assessment tests were carried out by using fiber grating sensors (fiber Bragg grating (FBG) and long-period grating (LPG)) as sensors of the arterial distention movement. Here we were focused on the possibility to record the STA pulsations in healthy volunteers when the sensors were just placed on the skin over the STA and fixed with the tape or elastic bandage. Our results show that with this type of application, LPG technology outperformed FBG in a sense of sensitivity and signal to noise ratio. The reason possibly lies in the fact that cladding modes generated by an LPG are much more affected by arterial distention than back-propagating core modes of an FBG [2]. By using LPG sensor we were able to record STA pulsations in all volunteers.VII International School and Conference on Photonics : PHOTONICA2019 : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 26-30; Belgrad