ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients

The provided database of 260 ECG signals was collected from patients with out-of-hospital cardiac arrest while treated by the emergency medical services. Each ECG signal contains a 9 second waveform showing ventricular fibrillation, followed by 1 min of post-shock waveform. Patients’ ECGs are made available in multiple formats. All ECGs recorded during the prehospital treatment are provided in PFD files, after being anonymized, printed in paper, and scanned. For each ECG, the dataset also includes the whole digitized waveform (9 s pre- and 1 min post-shock each) and numerous features in temporal and frequency domain extracted from the 9 s episode immediately prior to the first defibrillation shock. Based on the shock outcome, each ECG file has been annotated by three expert cardiologists, - using majority decision -, as successful (56 cases), unsuccessful (195 cases), or indeterminable (9 cases). The code for preprocessing, for feature extraction, and for limiting the investigation to different temporal intervals before the shock is also provided. These data could be reused to design algorithms to predict shock outcome based on ventricular fibrillation analysis, with the goal to optimize the defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation and/or drug administration) for enhancing resuscitation. © 202

High-density optical interconnects based on self-imaging in coupled waveguide arrays

Rapidly increasing demand for higher data bandwidths has motivated exploration of new communication channels based on spatially multiplexed in-fibre and on-chip coupled light guides. However, the conventionally used periodically arranged coupled waveguides display complicated light propagation patterns, ranging from quasiperiodic to nearly chaotic. Taking a different approach, we spectrally engineer interwaveguide coupling to instigate self-imaging of the input light state at the array output and thus enable construction of novel high-fidelity interconnects. Simple implementation via modulation of the interwaveguide separations makes these interconnects realizable in all fabrication platforms. Their competitive advantages are negligible crosstalk-induced information loss, high density that exceeds the current standards by an order of magnitude, and compatibility with both classical and quantum information encoding schemes. Moreover, the wavelength-dependent self-imaging opens up new possibilities for wavelength and spatial division demultiplexing. The proposed analytical designs are supported by extensive numerical simulations of silicon-on-insulator, silicon nitride and silica glass waveguide arrays, and a statistical feasibility study. © 2023 Elsevier Lt

A New Method for Multi-Bit and Qudit Transfer Based on Commensurate Waveguide Arrays

Faithful parallel transfer of bits of information between computer components is a necessary condition for fast classical and quantum computation. Moreover, it has recently been suggested that the stability of quantum computation may be increased by using qudits and their representations as multiple qubits [1]. Transfer of an n-qudit and n qubits require number of channels that scale linearly and exponentially with n, respectively. This puts strict demands on dense packaging and scalability of interconnects. However, the transfer through densely packed optical interconnects is impeded by cross-talk between them. Proposed solutions to this problem entail high index-contrast waveguides [2], wavelength multiplexing [3], multimode waveguides [4] and supermodes [5]. We propose a new method and the hardware for the parallel transfer of bits, qubits and qudit states. The method is based on the full state revivals in linearly coupled commensurate waveguide arrays (WGAs). Commensurability of eigenvalues enforces periodicity of light dynamics and hence, full phase and amplitude revivals of the initial state. An n-element array can faithfully transfer an n-bit classical state and a quantum state encoded in an n-dimensional basis. The latter enables transfer of log2n qubits and an n-qudit. However, while the arrays with n<4 waveguides are always commensurate, the eigenvalues of longer arrays are commensurate only for certain ratios of their coupling coefficients. The key challenge in engineering of commensurate arrays is to find these ratios by solving the non-trivial inverse eigenvalue problem. Such problems are analytically solvable in a small number of cases and are, in general, of polynomial complexity. Analytical solutions have been reported for mirror-symmetric arrays composed of 4 or 5 optical waveguides [6]. Here, we present analytical solutions for arrays with up to 9 waveguides and use them to design commensurate WGAs that are accessible to modern fabrication techniques, such as direct laser writing [7].VI International School and Conference on Photonics and COST actions: MP1406 and MP1402 : PHOTONICA2017 : August 23 - September 1, 2017; Belgrade

Bend-free photonic integrated circuits with the crosstalk as a resource

We challenge the current thinking and approach to design of photonic integrated circuits (PICs), which are marked as drivers of the future information processing. Standard quantum PICs are composed of the unit cells based on directional couplers. The couplers typically consist of two waveguides bent to exhibit coupling in the proximity region. They conveniently produce the maximally entangled Bell state and have been used to construct functional optical quantum PICs [1]. However, their full exploitation faces the conceptual and technical challenges including the non-intrinsic scalability that requires waveguide branching, the radiation loss at waveguide bends and the therewith associated high-density packaging limit [2]. Arrays of linearly coupled parallel waveguides have been considered a viable alternative. However, the intricate inverse design of the corresponding Hamiltonians has limited their applications to the particular instances of the quantum logic gates obtained by numerical optimization procedures and machine learning [3, 4] and the simulators of the condensed matter systems, such as spin and Bloch arrays with the Wannier-Stark ladder spectrum [5]. A generic design solution based on a common physical and mathematical principle has not been reached. We propose a new concept for the design of bend-free high-density PICs composed exclusively of the linearly coupled commensurable waveguide arrays (CWGA). Their operation is based on the periodic continuous quantum walk of photons and leverages on the engineered waveguide coupling. We discuss the class of analytically accessible designs with the eigenspectra that randomly sample the WannierStark ladder [6, 7]. The free choice of eigenfrequencies marks a clear distinction from the current photonic simulators and provides a variety of novel circuit layouts and functionalities. In particular, we rework the designs of interconnects for qubits and qudits, multiport couplers, entanglement generators and interferometers. The analytical results are corroborated numerically. Finally, we test the robustness of the proposed building blocks to the random variations in design parameters, with a view to defining acceptable fabrication tolerances.VIII International School and Conference on Photonics and HEMMAGINERO workshop : PHOTONICA2021 : book of abstracts; August 23-27, 2021; Belgrad

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

Evaluation of the use of incoherent light sources in fibre grating sensing for applications in non-invasive medical diagnostics

Optical fibre sensors have attracted much attention as noninvasive electrically immune multiparameter diagnostic tools. Optical fibre gratings - resonant structures inside fibres, enable localized and distributed high-precision measurement schemes for the use in cardiology, pulmonology, prosthetics, obstetrics, etc. Particular niche market is reserved for broadband LPG sensors, which expel light from the fibre core to the cladding and thus enable sensitive measurement of the external refractive index and curvature. With the new costcutting LPG fabrication methods on the raise the question of the source and detector cost gets into focus. While the broadband coherent sources are usually used in laboratory, the source and spectrum analyser costs are prohibitive for many field applications. In this paper, we evaluate the performance and cost-benefit of the incoherent source application. The sensor performance is assessed in terms of sensing precision and signal-to-noise signal quality for broadband and lateral edge sensing schemes. It is sufficient for basic heart and respiration rate monitoring, but fails to satisfy stricter requirements for medical diagnostics.10th International Conference on Electrical, Electronic and Computing Engineering (IcETRAN); June 5-8, 2023; East Sarajevo, Bosnia and Herzegovin

The influence of atrial flutter in automated detection of atrial arrhythmias - are we ready to go into clinical practice?”

ObjectiveTo investigate the impact of atrial flutter (Afl) in the atrial arrhythmias classification task. We additionally advocate the use of a subject-based split for future studies in the field in order to avoid within-subject correlation which may lead to over-optimistic inferences. Finally, we demonstrate the effectiveness of the classifiers outside of the initially studied circumstances, by performing an inter-dataset model evaluation of the classifiers in data from different sources.MethodsECG signals of two private and three public (two MIT-BIH and Chapman ecgdb) databases were preprocessed and divided into 10s segments which were then subject to feature extraction. The created datasets were divided into a training and test set in two ways, based on a random split and a patient split. Classification was performed using the XGBoost classifier, as well as two benchmark classification models using both data splits. The trained models were then used to make predictions on the test data of the remaining datasets.ResultsThe XGBoost model yielded the best performance across all datasets compared to the remaining benchmark models, however variability in model performance was seen across datasets, with accuracy ranging from 70.6% to 89.4%, sensitivity ranging from 61.4% to 76.8%, and specificity ranging from 87.3% to 95.5%. When comparing the results between the patient and the random split, no significant difference was seen in the two private datasets and the Chapman dataset, where the number of samples per patient is low. Nonetheless, in the MIT-BIH dataset, where the average number of samples per patient is approximately 1300, a noticeable disparity was identified. The accuracy, sensitivity, and specificity of the random split in this dataset of 93.6%, 86.4%, and 95.9% respectively, were decreased to 88%, 61.4%, and 89.8% in the patient split, with the largest drop being in Afl sensitivity, from 71% to 5.4%. The inter-dataset scores were also significantly lower than their intra-dataset counterparts across all datasets.ConclusionsCAD systems have great potential in the assistance of physicians in reliable, precise and efficient detection of arrhythmias. However, although compelling research has been done in the field, yielding models with excellent performances on their datasets, we show that these results may be over-optimistic. In our study, we give insight into the difficulty of detection of Afl on several datasets and show the need for a higher representation of Afl in public datasets. Furthermore, we show the necessity of a more structured evaluation of model performance through the use of a patient-based split and inter-dataset testing scheme to avoid the problem of within-subject correlation which may lead to misleadingly high scores. Finally, we stress the need for the creation and use of datasets with a higher number of patients and a more balanced representation of classes if we are to progress in this mission

Optical interconnects and filters based on waveguide arrays

Rapidly increasing demand for higher data bandwidths has motivated exploration of new communication channels based on spatially multiplexed in-fibre and on-chip coupled light guides [1]. However, the conventionally used periodically arranged coupled waveguides display complicated light propagation patterns, ranging from quasiperiodic to nearly chaotic. Taking a different approach, we spectrally engineer interwaveguide coupling to instigate self-imaging of the input light state at the array output and thus enable construction of novel high-fidelity interconnects [2]. Simple implementation via modulation of the interwaveguide separations makes these interconnects realizable in all fabrication platforms. Moreover, the wavelength dependent self-imaging opens up possibilities for construction of new multiplexing devices [3]. Here, we present designs of band-pass filters and dichroic splitters for VIS and NIR and propose the strategies for selection of their central wavelengths and bandwidths

Accurate Reconstruction of the 12-Lead Electrocardiogram From a 3-Lead Electrocardiogram Measured by a Mobile Device

Clinical outcomes of several acute conditions, including myocardial infarction (MI), the most common cause of death, can be improved by timely diagnostics based on electrocardiography (ECG). However, current diagnostic technologies include a large number of wired ECG electrodes, which require accurate placement by trained personnel. The ideal ECG device would be suitable for self-measurement, i.e., would have a small number of electrodes, be mobile or portable, and provide an accurate diagnosis. However, these aims have not been met using the same device. A recently developed handheld ECG device with three quasi-orthogonal leads opened the door for mobile assessment of the three-dimensional cardiac vector by self-measurement. We hypothesize that the information provided is sufficient for accurate reconstruction of the 12-lead ECG. We propose a reconstruction algorithm based on the segment-by-segment 4-matrix (4M) transformation applied to the P wave, QRS complex, ST segment, and T wave. The accuracy of the 4M method was tested using data obtained from 64 healthy volunteers. The 4M method reconstructed the standard 12-lead ECG with a 0.96 mean cross-correlation for all leads and provided meaningful clinical results. A back-to-back comparative study demonstrated the superiority of the proposed method over the traditional EASI method. In addition, the results provide evidence of the capability of the 3-lead 4M technology to accurately reconstruct the full cardiac vector from a single measurement, which distinguishes it from competition. Although further clinical investigation is necessary, wireless operation and high accuracy make the proposed method potentially suitable for remote monitoring and self-assessment