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The aim of this study was to evaluate changes in AV nodal properties during administration of metoprolol, using a novel ECG-based method for parameter estimation. The AV nodal parameters account for the probability of an impulse not passing through the fast pathway, the absolute refractory periods of the slow and fast pathways (aRPs and aRPf), representing the functional refractory period, and rel
The aim of this work is to develop a method for detection of brief episode paroxysmal atrial fibrillation (PAF). The proposed method utilizes four different features: RR interval irregularity, absence of P waves, presence of f-waves and noise level. The obtained features are applied to the Mamdani-type fuzzy inference method for decisionmaking. The performance was evaluated on one hundred 90 s lon
Intradialytic hypotension (IDH) is the most common complication during hemodialysis; early prediction and prevention of IDH would dramatically improve the living conditions for patients with end stage renal disease. A recently published study suggests that a decrease in the envelope of the photoplethysmograpy (PPG) signal can be used for predicting acute symptomatic IDH. In the present study, the
A method for respiratory rate estimation from electrocardiogram (ECG), based on variations in QRS complexes slopes, is evaluated over stress testing recordings. Besides the 12 standard, and the 3 vectorcardiogram (VCG), 2 additional leads derived from the VCG are analyzed. A total of 34 slope series were studied, 2 for each lead: slopes between the peaks of the Q and R waves, and between the peaks
The atrioventricular (AV) node plays a central role during atrial fibrillation (AF). We have recently proposed a statistical AV node model defined by parameters characterizing the arrival rate of atrial impulses, the probability of an impulse choosing either one of the dual AV nodal pathways, the refractory periods of the pathways, and the prolongation of refractory periods. All model parameters a
In the present work, f-wave morphology is characterized by principal component analysis and a novel temporal parameter defined by the cumulative normalized variance of the 3 largest principal components (r3). The 7-day behavior of persistent atrial fibrillation (AF) was studied in 9 patients using r3, AF frequency, and sample entropy (SampEn). Detection of circadian rhythms depended on the paramet
A novel method for QRST cancellation during atrial fibrillation (AF) is introduced for use in recordings with two or more leads. The method is based on an echo state neural network (ESN) which estimates the time-varying, nonlinear transfer function between two leads, one lead with atrial activity and another lead without, for the purpose of canceling ventricular activity. The performance is evalua
Acute hypotensive episodes are common during dialysis sessions, and represent a serious problem. Spectral analysis of heart rate variability (HRV) and barorrefle x sensitivity (BRS) is performed to study the behaviour of the autonomic nervous system (ANS) during the hemodialysis. The ratio between the low frequency (LF) and high frequency (HF) power of HRV, as well as BRS in the HF band, are signi
In this study, alterations in the cardiovascular system caused by ventricular premature beats (VPBs) are investigated by analyzing the photoplethysmographic (PPG) signal. A simple algorithm for PPG-based detection of VPBs is devised and evaluated, and then employed for the analysis of heart rate turbulence (HRT), here labelled "pulse rate turbulence" (PRT). The pulse transit time is also studied a
Heart rate turbulence (HRT) is commonly assessed by two parameters: turbulence onset (TO) and turbulence slope (TS), both obtained by averaging RR tachograms following a ventricular premature beat (VPB). It has been recently shown that a model-based detection-theoretical approach results in HRT indices outperforming TO/TS in identifying the presence or absence of HRT. The aim of this work is to ev
The abstract with its heading should not be more than 75 mm long. This is equivalent to 18 lines of text. Leave 1 line space at the bottom of the abstract before continuing with the next heading. The autonomic nervous system modulates atrial electrophysiology in atrial fibrillation (AF). The purpose of this study was (1) to non-invasively characterize the effects of exercise on atrial fibrillatory
Allmänmedicin är ett brett område som spänner över många sjukdomstillstånd, med fokus på patientcentrering. Inom många områden sker en snabb kunskapsutveckling och rekommendationer för utrednings- och behandlingsstrategier uppdateras hela tiden. För en allmänläkare kan det vara svårt att hålla sig uppdaterad och tidsbrist begränsar möjligheterna att leta kunskap i det dagliga kliniska arbetet. Dig
Noradrenergic locus coeruleus (LC) efferents to the forebrain suppress seizures in several models of epilepsy. Using in situ hybridization, we demonstrate that tyrosine hydroxylase (TH) and norepinephrine transporter (NET) but not vesicular monoamine transporter 2 (VMAT2) mRNA levels are transiently elevated in LC neurons following kainic acid-induced status epilepticus. These increases of TH and
2015 was a year of an unprecedented migration from the Middle East to Europe. Sweden received almost 163,000 asylum applications. The civil society, including the former state church, took a notable responsibility. In a situation where the welfare systems are increasingly strained, and both the welfare state and the majority church are re-regulated, we ask: how does this play out in local contexts
The effects of altered N-methyl-D-aspartate (NMDA) receptor subunit composition on seizure development in kindling epilepsy were assessed in transgenic mice expressing high neuronal levels of NR2D under control of the calcium/calmodulin kinase II alpha subunit (αCaMKII) promoter. The NR2D subunit is normally present at very low levels in the mature forebrain. Transgenic mice showed a marked reduct
The effects of changing NMDA receptor subunit composition on synaptic plasticity in the hippocampus were analyzed by creating transgenic mice overexpressing NR2D, a predominantly embryonic NMDA receptor subunit. NMDA-evoked currents in the transgenic mice had smaller amplitudes and slower kinetics. The transgenics also displayed age-dependent deficits in synaptic plasticity in area CA1 of the hipp
Formation of metal hydrides is a serious complication that occur when hydride forming metals such as zirconium, niobium, vanadium and magnesium are exposed to long term hydrogen environment. The main concern is that the hydride, as being a brittle material, has very poor fracture mechanical properties. Formation of hydride is associated with transportation of hydrogen along the gradients of increa
The electronic structure of monolayer hexagonal boron nitride grown on Ni by the diffusion and precipitation method was studied by x-ray absorption spectroscopy, emission spectroscopy, x-ray photoelectron spectroscopy and micro-ultraviolet photoemission spectroscopy. No indication of hybridization between h-BN π and Ni 3d orbitals was observed. That is, the monolayer h-BN was found to be in the qu
We have constructed a compact soft X-ray emission spectrometer at the BL-09A beamline of the NewSUBARU synchrotron radiation facility at the University of Hyogo, Japan. Using this spectrometer, we observed a large take-off angle dependence of C-K emissions in highly oriented pyrolytic graphite (HOPG). At an excitation photon energy of 310 eV, far from the absorption edge of HOPG, we detected large
