This document presents a new complete standalone system for a recognition of sleep apnea using signals from the pressure sensors placed under the mattress. The developed hardware part of the system is tuned to filter and to amplify the signal. Its software part performs more accurate signal filtering and identification of apnea events. The overall achieved accuracy of the recognition of apnea occurrence is 91%, with the average measured recognition delay of about 15 seconds, which confirms the suitability of the proposed method for future employment. The main aim of the presented approach is the support of the healthcare system with the cost-efficient tool for recognition of sleep apnea in the home environment.

The ballistocardiography is a technique that measures the heart rate from the mechanical vibrations of the body due to the heart movement. In this work a novel noninvasive device placed under the mattress of a bed estimates the heart rate using the ballistocardiography. Different algorithms for heart rate estimation have been developed.

Methods based exclusively on heart rate hardly allow to differentiate between physical activity, stress, relaxation, and rest, that is why an additional sensor like activity/movement sensor added for detection and classification. The response of the heart to physical activity, stress, relaxation, and no activity can be very similar. In this study, we can observe the influence of induced stress and analyze which metrics could be considered for its detection. The changes in the Root Mean Square of the Successive Differences provide us with information about physiological changes. A set of measurements collecting the RR intervals was taken. The intervals are used as a parameter to distinguish four different stages. Parameters like skin conductivity or skin temperature were not used because the main aim is to maintain a minimum number of sensors and devices and thereby to increase the wearability in the future.

BACKGROUND Stroke volume response during stress is a major determinant of functional status in heart failure and can be measured by two-dimensional (2-D) volumetric stress echocardiography (SE). The present study hypothesis is that SE may identify mechanisms underlying the change in stroke volume by measuring preload reserve through end-diastolic volume (EDV) and left ventricular contractile reserve (LVCR) with systolic blood pressure and end-systolic volume (ESV). METHODS We enrolled 4,735 patients (age 63.6 ± 11.3 yrs, 2800 male) referred to SE for known or suspected coronary artery disease (CAD) and/or heart failure (HF) in 21 SE laboratories in 8 countries. In addition to regional wall motion abnormalities (RWMA), force was measured at rest and peak stress as the ratio of systolic blood pressure by cuff sphygmomanometer/ESV by 2D with Simpson's or linear method. Abnormal values of LVCR (peak/rest) based on force were ≤1.10 for dipyridamole (n=1,992 patients) and adenosine (n=18); ≤2.0 for exercise (n=2,087) or dobutamine (n=638). RESULTS Force-based LVCR was obtained in all 4,735 pts. Lack of stroke volume increase during stress was due to either abnormal LVCR and/or blunted preload reserve, and 57 % of patients with abnormal LVCR nevertheless showed increase in stroke volume. CONCLUSIONS Volumetric SE is highly feasible with all stresses, and more frequently impaired in presence of ischemic RWMA, absence of viability and reduced coronary flow velocity reserve. It identifies an altered stroke volume response due to reduced preload and/or contractile reserve.

Diffusion magnetic resonance imaging is a noninvasive imaging modality that has been extensively used in the literature to study the neuronal architecture of the brain in a wide range of neurological conditions using tractography. However, recent studies highlighted that the anatomical accuracy of the reconstructions is inherently limited and challenged its appropriateness. Several solutions have been proposed to tackle this issue, but none of them proved effective to overcome this fundamental limitation. In this work, we present a novel processing framework to inject into the reconstruction problem basic prior knowledge about brain anatomy and its organization and evaluate its effectiveness using both simulated and real human brain data. Our results indicate that our proposed method dramatically increases the accuracy of the estimated brain networks and, thus, represents a major step forward for the study of connectivity.

A new method substantially improves the accuracy of mapped brain networks using anatomy and microstructure informed tractography. Diffusion magnetic resonance imaging is a noninvasive imaging modality that has been extensively used in the literature to study the neuronal architecture of the brain in a wide range of neurological conditions using tractography. However, recent studies highlighted that the anatomical accuracy of the reconstructions is inherently limited and challenged its appropriateness. Several solutions have been proposed to tackle this issue, but none of them proved effective to overcome this fundamental limitation. In this work, we present a novel processing framework to inject into the reconstruction problem basic prior knowledge about brain anatomy and its organization and evaluate its effectiveness using both simulated and real human brain data. Our results indicate that our proposed method dramatically increases the accuracy of the estimated brain networks and, thus, represents a major step forward for the study of connectivity.

INTRODUCTION: Gastrointestinal symptoms in irritable bowel syndrome (IBS) have been correlated with psychological factors using retrospective symptom assessment. However, real-time symptom assessment might reveal the interplay between abdominal and affective symptoms more reliably in a longitudinal perspective. The aim was to evaluate the association between stress and abdominal pain, using the Experience Sampling Method (ESM) as a real-time, repeated measurement method. METHODS: Thirty-seven patients with IBS (26 women; mean age 36.7 years) and 36 healthy controls (HC; 24 women; mean age 31.1 years) completed an electronic ESM during 7 consecutive days. Abdominal pain and stress were scored on an 11-point Numeric Rating Scale at a maximum of 10 random moments each day. RESULTS: Abdominal pain scores were 2.21 points higher in patients with IBS compared with those in HC (P < 0.001), whereas stress levels did not differ significantly (B: 0.250, P = 0.406). In IBS, a 1-point increase in stress was associated with, on average, 0.10 points increase in abdominal pain (P = 0.017). In HC, this was only 0.02 (P = 0.002). Stress levels at t = −1 were not a significant predictor for abdominal pain at t = 0 in both groups, and vice versa. DISCUSSION: Our results demonstrate a positive association between real-time stress and abdominal pain scores and indicate a difference in response to stress and not a difference in experienced stress per se. Furthermore, an in-the-moment rather than a longitudinal association is suggested. This study underlines the importance of considering the individual flow of daily life and supports the use of real-time measurement when interpreting potential influencers of abdominal symptoms in IBS.

Lung sound (LS) signals are often contaminated by impulsive artifacts that complicate the estimation of lung sound intensity (LSI) using conventional amplitude estimators. Fixed sample entropy (fSampEn) has proven to be robust to cardiac artifacts in myographic respiratory signals. Similarly, fSampEn is expected to be robust to artifacts in LS signals, thus providing accurate LSI estimates. However, the choice of fSampEn parameters depends on the application and fSampEn has not previously been applied to LS signals. This study aimed to perform an evaluation of the performance of the most relevant fSampEn parameters on LS signals, and to propose optimal fSampEn parameters for LSI estimation. Different combinations of fSampEn parameters were analyzed in LS signals recorded in a heterogeneous population of healthy subjects and chronic obstructive pulmonary disease patients during loaded breathing. The performance of fSampEn was assessed by means of its cross-covariance with flow signals, and optimal fSampEn parameters for LSI estimation were proposed.

Cardiovascular disease (CVD) is the biggest cause of sickness and mortality worldwide in both males and females. Clinical statistics demonstrate clear sex differences in risk, prevalence, mortality rates, and response to treatment for different entities of CVD. The reason for this remains poorly understood. Non-coding RNAs (ncRNAs) are emerging as key mediators and biomarkers of CVD. Similarly, current knowledge on differential regulation, expression, and pathology-associated function of ncRNAs between sexes is minimal. Here, we provide a state-of-the-art overview of what is known on sex differences in ncRNA research in CVD as well as discussing the contributing biological factors to this sex dimorphism including genetic and epigenetic factors and sex hormone regulation of transcription. We then focus on the experimental models of CVD and their use in translational ncRNA research in the cardiovascular field. In particular, we want to highlight the importance of considering sex of the cellular and pre-clinical models in clinical studies in ncRNA research and to carefully consider the appropriate experimental models most applicable to human patient populations. Moreover, we aim to identify sex-specific targets for treatment and diagnosis for the biggest socioeconomic health problem globally.

Long QT syndrome (LQTS) is a rare (1:2500–1:10,000) inherited disorder characterized by the onset of arrhythmogenic syncope, polymorphic ventricular tachycardia, and sudden cardiac death. The aim of this article was to describe an unexpected success with an unusual therapeutic modality of a patient diagnosed with LQTS syndrome (suspected Romano–Ward syndrome) during an 8-year period. A 59-year-old female patient was admitted to the hospital due to chest pain and nausea, and after diagnostic and therapeutical approach, a permanent dual-chamber rate-modulated (DDDR) pacemaker was implanted instead of the implantable cardioverter defibrillator (ICD). During the 8-year period, the patient remained stable, without rhythm disorder. Romano–Ward syndrome as a congenital LQTS carries a high risk of sudden cardiac death and presents an indication for ICD. In this patient, for objective reasons, this could not be performed. Implantation of a DDDR with an appropriate pharmacological therapy, including propranolol, in this case, proved to be a successful therapeutic modality.

Introduction: The head-up tilt table test is noninvasive diagnostic procedure, which is used in the diagnosis of syncope. Syncope presents a benign short-term disorder of cerebral circulation with the sudden loss of consciousness and muscle tone. Aim: The aim is to present not only the role and importance of orthostatic tests in the daily clinical practice of pediatric cardiology, neuropediatrics but also pediatrics in general. Patients and Methods: This study has retrospective descriptive character and included the period from April 1997 to June 2020, during which the registration and analysis of orthostatic stability tests (head-up/tilt table test, tilt table test) was performed. Medical documentation of outpatient and hospitalized patients on the Paediatric Clinic of Clinical Center University of Sarajevo (Register of Tilt Table Test) was used. Results: During this period, 1029 tests were registered and analyzed. Modification test (head-up) was performed in 132 (12.8%) patients, and since 2008, classic tilt table test was performed in 897 (87.1%) patients. Patients were 6.5–19 years old, with a predominance of female patients 611 (59.4%). There were 519 (50.4%) patients who were 15–19 years old and 510 (49.6%) patients who were under 15 years of age. Indications were syncope or suspected syncope in 671 (65.2%) patients, cardiovascular etiology (arrhythmias, chest pain, congenital heart defects [CHDs], surgically corrected CHDs, hypotension, and hypertension) in 195 (19%) patients, neuropediatric pathology (epilepsia, suspected epilepsia, headache, vertigo) in 101 (9.8%) patients, and other indications in 62 (6.03%) patients. From the total number of tests, 862 were first tests (83.4%) and 167 were control tests (16.3%). The positive test was found in 538 (52.3%) patients, most often vasovagal syncope (473 patients or 87.9%). Conclusion: Tilt table test is a reliable diagnostic tool in examining the etiology of syncope, primarily vasovagal, and is an extremely important method primarily in cardiopediatric and neuropediatric daily diagnostics.

We propose a framework for designing observers possessing global convergence properties and desired asymptotic behaviors for the state estimation of nonlinear systems. The proposed scheme consists in combining two given continuous-time observers: One, denoted as global, ensures (approximate) convergence of the estimation error for any initial condition ranging in some prescribed set, while the other, denoted as local, guarantees a desired local behavior. We make assumptions on the properties of these two observers, and not on their structures, and then explain how to unite them as a single scheme using hybrid techniques. Two case studies are provided to demonstrate the applicability of the framework. Finally, a numerical example is presented.

We study the design of state observers for nonlinear networked control systems (NCSs) affected by disturbances and measurement noise, via an emulation-like approach. That is, given an observer designed with a specific stability property in the absence of communication constraints, we implement it over a network, and we provide sufficient conditions on the latter to preserve the stability property of the observer. In particular, we provide a bound on the maximum allowable transmission interval (MATI) that guarantees an input-to-state stability (ISS) property for the corresponding estimation error system. The stability analysis is trajectory-based, utilizes small-gain arguments, and exploits a persistently exciting property of the scheduling protocols. This property is key in our analysis and allows us to obtain significantly larger MATI bounds in comparison to the ones found in the literature. Our results hold for a general class of NCSs; however, we show that these results are also applicable to NCSs implemented over a specific physical network called WirelessHART (WH). The latter is mainly characterized by its multihop structure, slotted communication cycles, and the possibility to simultaneously transmit over different frequencies. We show that our results can be further improved by taking into account the intrinsic structure of the WH–NCS model. That is, we explicitly exploit the model structure in our analysis to obtain an even tighter MATI bound that guarantees the same ISS property for the estimation error system. Finally, to illustrate our results, we present analysis and numerical simulations for a class of Lipschitz nonlinear systems and high-gain observers.