BACKGROUND:Variants in the KCNQ1 underlie type 1 long QT syndrome. The clinical manifestations are influenced by the specific KCNQ1 pathogenic variant. OBJECTIVE:We aimed to describe the phenotype in patients found to possess the p.Gln530Ter-KCNQ1 pathogenic variant common in Scandinavian patients with long QT syndrome. METHODS:Clinical characteristics of p.Gln530Ter-KCNQ1 variant-positive patients from 6 university hospital registries in Sweden, Denmark, Norway, and the United States were compared with carriers of other KCNQ1 pathogenic variants (non-p.Gln530Ter-KCNQ1) and gene-negative controls. Cardiac events (CEs) encompassed syncope of unknown origin and ventricular arrhythmias (VAs) (episodes of torsades de pointes, appropriate implantable cardioverter-defibrillator shocks, aborted cardiac arrest, or sudden cardiac death). RESULTS:The p.Gln530Ter-KCNQ1, non-p.Gln530Ter-KCNQ1, and control groups included 139 (65% female; 24% probands; mean age at end of follow-up 51 ± 20 years), 194 (65% female; mean age 44 ± 19), and 717 individuals (55% female; mean age 39 ± 24), respectively. CEs by 60 years of age were reported in 30 of the p.Gln530Ter-KCNQ1 group (22%; of those 5 VA, all nonfatal), 46 of the non-p.Gln530Ter-KCNQ1 group (24%; 4 VA, all nonfatal), and 81 of controls (11%; no VA). In the p.Gln530Ter-KCNQ1 group, CE occurred at a significantly older age than in the non-p.Gln530Ter-KCNQ1 group (44 ± 22 vs 31 ± 22; P = .02). Before 30 years of age, CE risk in the p.Gln530Ter-KCNQ1 group did not differ from that in controls (adjusted hazard ratio 1.11 [95% confidence interval 0.65-1.89]; P = .707) and was significantly lower than in the non-p.Gln530Ter-KCNQ1 group. After 30 years of age, CE risk in the p.Gln530Ter-KCNQ1 group increased significantly (adjusted hazard ratio 3.21 [95% confidence interval 1.49-6.92]; P = .003, compared with controls) and did not differ from the non-p.Gln530Ter-KCNQ1 group. CONCLUSION:The p.Gln530Ter-KCNQ1 variant is associated with a later onset of CE than other KCNQ1 pathogenic variants.

ECG in Brugada syndrome (BrS) is characterized by a ST-segment elevation in the right precordial leads. Overlap between ST-segment changes in BrS and ischemia may lead to diagnostic challenges. We report a case of a male patient presented with recurrent chest pain episodes and ST elevation in the right precordial leads consistent with Brugada ECG pattern type 1 and was clinically diagnosed with BrS at the age of 30 years. During follow up the patient developed acute myocardial infarction with pronounced ST depression in the right precordial leads, masking the Brugada pattern of the baseline ECG.

We study the possibility of using machine-learning algorithms to optimize the prediction of state-to-state (STS) dissociation rate coefficients in modeling nonequilibrium air flows. A rigorous but computationally complex theoretical model of reaction-rate coefficients, which considers the electronic and vibrational excitation of all reaction participants (products and reagents), is taken as a basis. Several algorithms are considered for predicting the STS dissociation rate coefficients of air components: k-nearest neighbors (k-NN) and decision tree (DT) regression, as well as neural networks; their accuracy and efficiency are analyzed. It is shown that the use of regression (k-NN and DT) algorithms is inappropriate for our problem, while neural-network algorithms have clear advantages over classical regression algorithms in terms of time and scalability. Validation of the neural-network approach is carried out by considering the example of solving the problem of vibrational-chemical relaxation behind a shock wave. A satisfactory agreement with the experiment and almost complete coincidence of the results with the solution obtained by theoretical methods without the use of machine learning are shown. The approach to data representation and processing proposed in this paper is easily scalable to more complex models taking into account the excitation of internal degrees of freedom. Thus, when taking into account the electronic excitation of a molecule, acceleration of about 1–2 orders is achieved without significant loss of accuracy. As a result, this study demonstrates that the use of neural-network methods makes it possible to predict state-specific reaction-rate coefficients with a high degree of accuracy without performing direct calculations using resource-intensive theoretical formulas directly in the working code. The approach scales as the complexity of the formulation increases (as is shown in the case of taking into account the electronic-vibrational excitation of the reagents), which allows us to reduce the time required to perform the calculations. At the same time, such a result is achieved through serious preliminary work and requires the development of large arrays of preliminary data. If we automate this process using a neural network, we can obtain a computationally efficient tool for systematic predictions of state-to-state reaction-rate coefficients.

Abstract Background T-wave inversion (TWI) in standard ECG leads is a proven risk marker for life-threatening ventricular arrhythmias (VA) in arrhythmogenic right ventricular cardiomyopathy (ARVC). Right-sided precordial leads (RSPL), which may be more sensitive for detection of the arrhythmogenic substrate, are rarely recorded and understudied in this context. Computerized ECG signal-processing allows synthesis of right-sided precordial ECG leads derived from standard 12-lead ECG. Objective We aimed to assess the value of TWI in RSPL, synthetized from the standard 12-lead ECG, for prediction of VA risk in ARVC patients with subtle ECG phenotypes. Methods Patients with definite ARVC by TFC2010 and no history of sustained VA prior to diagnosis from the Nordic, Canadian and Dutch ARVC registries were included. Patients with major repolarization criterion or complete right bundle branch block (RBBB) were excluded. RSPL (V3R-V6R) were derived from digitally recorded eight linearly independent leads (I, II and precordial V1 to V6) of the standard ECG using a linear ECG transformation matrix. The matrix was previously developed based on a library of body surface potential maps from a mixed group of healthy subjects and patients with cardiac diseases using multivariate linear regression and QRS-T data obtained from averaged beats of the right-sided-precordial leads and the basis leads. TWI exceeding 0.1 mV in any of the synthetized leads was tested for its ability to predict sustained VA, defined as either sustained ventricular tachycardia, appropriate ICD shock, aborted cardiac arrest, or sudden cardiac death. In a similar manner, the value of TWI in any of the inferior leads III, aVF or II was assessed. Hazard ratio was calculated using Cox regression analysis adjusted for age, sex, and proband status. Results In total, 144 patients without prior VA history were identified. After exclusion of patients with major repolarization criterion (n=37) and RBBB (n=11), 96 patients comprised the study group (mean age 40±16, 42% female, 41% probands, 48% ICD carriers). Fifty-nine patients (62%) had TWI in one or more synthetized RSPL and 33 patients (34%) had TWI in any of the inferior leads. During 10 years of follow-up, 11 patients (12%) developed VA. Kaplan-Meier curve analysis showed significant association between the presence of TWI in at least one of the RSPL and the risk of VA, which remained an independent predictor in the adjusted Cox regression analysis (HR 10.6, 95%CI 1.3-84.4, p=0.026). TWI in any of the inferior leads was not associated with the risk of VA in this cohort (HR 1.2 95%CI 0.26-5.42). Conclusions Synthetized right-sided precordial leads appear to contain information potentially useful for refining risk stratification of primary prevention ARVC patients with a subtle ECG phenotype, in whom traditional repolarization markers, such as major repolarization criterion or TWI in inferior leads, are not informative.

In simulations of strongly non-equilibrium gas flows, the most accurate results are obtained by detailed state-resolved approach. Modeling state-to-state vibrational-chemical kinetics requires data on the rate coefficients of chemical reactions depending on the vibrational states of reacting molecules. The present paper analyzes several previously described models of state-resolved reaction rate coefficients for air components. Using the data of state-of-the-art quasiclassical trajectory calculations, the simple semi-empirical Treanor‒Marrone model with dissociation from any vibrational level is improved. For this purpose, the parameter of model U is represented as a function of temperature and vibrational energy of reagents. For all dissociation reactions in air, recommendations are given on the optimal choice of parameters in the Arrhenius law and in the Treanor‒Marrone model; the suggested parameters provide an excellent agreement with the results of trajectory calculations in the temperature range of 1000–20 000 K for the entire range of vibrational energies of molecules. For Zeldovich exchange reactions, a simple and effective model is proposed, taking into account the vibrational excitation of both reagents and products.

The value of signal-averaged ECG (SAECG) derived ventricular late potentials (LP) as a minor depolarization criterion of arrhythmogenic right ventricular cardiomyopathy (ARVC) has been debated. Another criterion from the same category, terminal activation duration (TAD>55 ms), is obtained from standard V1 ECG lead, which makes it easier for use. However little data exist regarding the relationship between structural right ventricular (RV) ARVC substrate, LP and TAD.

In arrhythmogenic right ventricular cardiomyopathy (ARVC), minor depolarization criteria by TFC2010 include ventricular late potentials (LP) assessed using signal-averaged ECG (SAECG) and terminal activation duration (TAD). TAD is measured from a standard V1 lead, which favors its use in clinical practice, however its ability to fully replace LP in ARVC workup is not clear.

The aim of this study is to assess the value of P-wave morphology markers in sinus rhythm to predict the imminence of atrial fibrillation (AF) episodes in patients with paroxysmal AF (PxAF). P-wave signal-to-noise ratio (SNR) is emphasized by signal processing methods based on principal component (PCA) and periodic component (πCA), together with time averaging analysis. The P-wave morphology features considered are: total power, relative power components, power at high frequency bands (as a measure of rugosity) and P-wave duration. Features are evaluated at three different five-minute time intervals before AF episode occurrences (at 5 minutes, 30 minutes and 60 minutes before the episode onset) in PxAF patients. Results show that in PxAF patients the relative power of the second-to-first principal component increases and the mean duration of the first principal and periodic P-wave component also increases when the time interval gets closer to the AF episode onset. No significant differences were observed in P-wave rugosity by none of both methods. These findings can be interpreted as P wave becoming more complex and wider at the imminence of AF episodes.

This article describes the results of the anomalies automated detection algorithm development in the operation of industrial robots. The development of robotic systems, in particular, industrial robots, and software for them is ahead of the tracking and managing technologies development. The operation of the digital production system involves the generation of a large amount of various data characterizing the state of both the specific equipment and the industrial system as a whole. Such a system produces a sufficient amount of data to develop machine learning models to analyse this data to solve problems such as forecasting and modelling. As part of the study, an experiment was conducted based on the equipment of the laboratory of industrial robots of Tomsk Polytechnic University. In the course of the research, the industrial manipulator moved loads belonging to different classes by weight. An algorithm was developed for the automated analysis of the values of the parameters of the consumed current and the position of the manipulator.

In the present study, we propose a general model for state-resolved reaction rate coefficients. The model combines the main advantages of several theoretical models for preferential dissociation and exchange reactions coupled to vibrational relaxation. Vibrational and electronic excitation of all species participating in the reaction is taken into account. The complete set of parameters for state-resolved chemical reactions in five-component air is obtained by fitting the results of the most reliable quasi-classical trajectory simulations in the temperature range 2000–15000 K.

Abstract Funding Acknowledgements Type of funding sources: None. Left atrial (LA) functional abnormalities, including LA strain (LAS) and strain rate (LASR) reduction, are observed in patients with left ventricular diastolic disfunction (LVDD). However, the degree of reduction at different stages of LVDD is not fully clarified. We aimed to assess the interdependence between LAS and LASR parameters and LVDD grades in subjects of advanced age with preserved ejection fraction (EF). Material and methods Consecutive patients, who underwent echocardiography within 12 months, were screened and included into the study in case of age older than 65 years, preserved EF, sinus rhythm at the time of study and preserved dataset of sufficient quality for speckle tracking analysis. LAS and LASR parameters, including LAS and peak LASR during reservoir, conduit, and contractile phases were calulated with single plane apical 4-chamber view assessment. One-way ANOVA analysis with Bonferroni correction was used to assess the difference between groups. Results Among 153 patients (mean age 74 ± 7 years; 105 female, mean EF 64 ± 5%) included in the study there were 38 patients with no evidence of LVDD, 67 with LVDD grade 1, 40 with LVDD grade 2, and 5 with LVDD grade 3. The values of LAS and LASR parameters for these groups are summarized in Table. All parameters were significantly reduced in grade 2 and 3 LVDD patients comparing to the patients with no LVDD. Contractile phase LAS and LASR were slightly higher in grade 1 than in no LVDD patients. Reservoir and conduit phase LAS and LASR were lower in grade 1 LVDD comparing to no LVDD, but only for conduit phase parameters the difference was significant. In ROC analysis for conduit phase LAS and LASR to be associated with the presence of LVDD of any grade the area under the curve was 0,707 (p < 0.001) and 0,742 (p < 0.001) respectively. Conclusion Impaired LA function is seen in patients with LVDD. Whereas measurements characterizing LA reservoir and contractile functions demonstrate significant decrease at advanced stages of LVDD, conduit function is significantly reduced at grade 1 LVDD, providing the possibility for early detection of LVDD. Group LAS (%) LASR (1/sec) reservoir conduit contractile reservoir conduit contractile No LVDD, n = 38 29,7 ± 9,3 †‡ 15,1 ± 6,6 §†‡ 14,6 ± 5,4 †‡ 1,28 ± 0,37 †‡ 1,18 ± 0,44 §† 1,68 ± 0,60 †‡ Grade 1, n = 69 28,6 ± 8,9 †‡ 11,6 ± 6,2 ƒ 17,0 ± 5,7 †‡ 1,23 ± 0,43 ‡ 0,90 ± 0,38 ƒ 1,99 ± 0,71 †‡ Grade 2, n = 40 19,1 ± 7,1 ƒ§ 9,2 ± 4,5 ƒ 9,9 ± 4,4 ƒ§ 0,87 ± 0,26 ƒ§ 0,72 ± 0,27 ƒ 1,07 ± 0,44 ƒ§ Garde 3, n = 5 13,8 ± 3,6 ƒ§ 7,7 ± 2,5 ƒ 6,1 ± 2,2 ƒ§ 0,8 ± 0,29 ƒ 0,75 ± 0,28 0,67 ± 0,27 ƒ§ Significant difference (p < 0,05): ƒ – with No LVDD, § – with Grade 1 LVDD, † – with Grade 2 LVDD, ‡ – with Grade 3 LVDD

In the present paper non-equilibrium flows of CO 2 /CO/O 2 /O/C mixture behind shock waves is studied taking into account vibrational excitation of CO 2 , CO, O 2 molecules. The kinetic scheme includes vibrational energy transitions, dissociation, recombination and exchange chemical reactions. The problem is solved in the five-temperature kinetic theory approximation. The equations for vibrational temperatures of symmetric–bending and asymmetric CO 2 modes and for diatomic species are coupled to the gas dynamic equations and applied to study flow parameters in the relaxation zone behind shock waves. Different models for one-temperature and multi-temperature rates of chemical reactions are used in calculations and the influence of exchange reactions and reaction models on flow parameters in the relaxation zone behind the shock wave is studied in the paper.

Several state-resolved and two-temperature models for the rate coefficients of reaction CO+CO=CO2+C are assessed, and a new simple state dependent model is proposed. Various models for the two-temperature non-equilibrium factor are considered: the theoretical alpha-model and the models based on averaging the state-resolved rate coefficients over the Boltzmann distribution. It is shown that for the Starik model, taking into account vibrational excitation of the partner CO molecule as well as the reaction product does not affect the two-temperature reaction rate coefficients. If the vibrational excitation of only one CO molecule is taken into account, the Starik model and that proposed in this work with the parameter U = ∞ yield identical results. However, our model is more general since it is capable to account for the preferential reaction mechanism from high vibrational states. Two-temperature rate coefficients provided by the a-model agree well with the averaged state-to-state ones, but the parameter α cannot be fixed in the entire temperature range and has to be chosen according to the specific ratio T/Tv. Thus, our computationally efficient state-specific model is recommended for state-to-state flow simulations; when being averaged with different non-equilibrium vibrational distributions, it can be used for modeling two-temperature flows.

In this paper new multi-temperature models for rate coefficients of non-equilibrium chemical reactions in mixtures containing CO2 molecules are derived on the basis of the kinetic theory. The models are obtained by averaging of state-dependent reaction rate coefficients, found previously, over multi-temperature vibrational distributions. Five-temperature, three-temperature and two-temperature non-equilibrium distributions are considered and comparison of reaction rate coefficients derived using these distributions as well as the thermal equilibrium one-temperature model is presented. The proposed rate coefficients are used in the governing equations for vibrational and chemical relaxation in the five-component mixture CO2/CO/O2/C/O. The solution of these equations is obtained in the five-temperature, three-temperature, two-temperature and one-temperature approaches. Finally, the influence of chemical reaction models on macroscopic mixture parameters is discussed in the paper.

Studies investigating risk factors associated with atrial fibrillation (AF) have mostly focused on AF presence and burden, disregarding the temporal distribution of AF episodes although such information can be relevant. In the present study, the alternating, bivariate Hawkes model was used to characterize paroxysmal AF episode patterns. Two parameters: the intensity ratio µ, describing the dominating rhythm (AF or non-AF) and the exponential decay β 1, providing information on clustering, were investigated in relation to AF burden and atrial echocardiographic measurements. Both µ and β1were weakly correlated with atrial volume (r=0.19 and r=0.34, respectively), whereas µ was correlated with atrial strain (r=-0.74, p≤0.1) and AF burden (r=0.68, p≤0.05). Weak correlation between β1 and AF burden was found (r=0.29). Atrial structural remodeling is associated with changes in AF characteristics, often manifested as episodes of increasing duration, thus µ may reflect the degree of atrial electrical and structural remodeling. Moreover, clustering information (β1) is complementary information to AF burden, which may be useful for understanding arrhythmia progression and risk assessment of ischemic stroke.