In Silico Comparison of Phase Maps Based on Action Potential and Extracellular Potential

In this work, a computer simulation of the reentrant ventricular tachycardia (VT) was used to investigate the peculiar properties of phase maps based on transmembrane potentials (TP) and extracellular potentials (EP). The simulation approach included the bidomain model with full myocardium-torso coupling, a realistic ionic model of the human cardiomyocytes and a personalized geometry of the heart and torso. The phase mapping pipeline includes a signal detrending and the Hilbert transform. It was demonstrated that TP-based phase maps correlated well with the propagation of cardiac excitation. In contrast, EP-based phase mapping provides some aberrations which can complicate electrophysiological interpretation of the phase maps in terms of cardiac activation sequence. It was also shown that a modification of the phase computation algorithm, including the sign inversion of signals and a special transformation of the phase plot, can partially eliminate these aberrations and make EP-based phase maps resemble TP-based maps. © 2018 Creative Commons Attribution.Russian Foundation for Basic Research, RFBR: 18-31-00401The reported study was funded by RFBR according to the research project No. 18-31-00401. Development of computer model with personalized geometry was funded by IIP UrB RAS theme No AAAA-A18-118020590031-8, RF Government Act #211 of March 16, 2013 (agreement 02.A03.21.0006), Program of the Presidium RAS #27 (project AAAA-A18-118020590030-1)

Role of myocardial properties and pacing lead location on ECG in personalized paced heart models

Personalised cardiac models were built from the computed tomography imaging data for two patients with implanted cardiac resynchronisation therapy devices. The cardiac models comprised a biventricular model of myocardial electrophysiology coupled with a model of the torso to simulate the body surface potential map. The models were verified against electrocardiogams (ECG) recorded in the patients from 240 leads on the body surface under left ventricular pacing. The simulated ECG demonstrated a significant sensitivity to the myocardial anisotropy and location of the pacing electrode tip in the models. An apicobasal cellular heterogeneity was shown to be less significant for the ECG pattern at the paced-ventricle activation than that showed earlier by Keller and co-authors (2012) for the normal activation sequence. © 2017 IEEE Computer Society. All rights reserved.This study was supported by the RAS Presidium Programme I.33Π, and Government of the Russian Federation (agreement 02.A03.21.0006). We used the computational clusters of Ural Federal University and ”URAN” of Institute of Mathematics and Mechanics (Ekaterinburg)

Sentinel headache as a warning symptom of ischemic stroke

Background: There are no previous controlled studies of sentinel headache in ischemic stroke. The purpose of the present study was to evaluate the presence of such headache, its characteristics and possible risk factors as compared to a simultaneous control group. Methods: Eligible patients (n = 550) had first-ever acute ischemic stroke with presence of new infarction on magnetic resonance imaging with diffusion-weighted imaging (n = 469) or on computed tomography (n = 81). As a control group we studied in parallel patients (n = 192) who were admitted to the emergency room without acute neurological deficits or serious neurological or somatic disorders. Consecutive patients with stroke and a simultaneous control group were extensively interviewed soon after admission using validated neurologist conducted semi-structured interview forms. Based on our previous study of sentinel headache in transient ischemic attacks we defined sentinel headache as a new type of headache or a previous kind of headache with altered characteristics (severe intensity, increased frequency, absence of effect of drugs) within seven days before stroke. Results: Among 550 patients with stroke 94 patients (17.1%) had headache during seven days before stroke and 12 (6.2%) controls (p < 0.001; OR 3.9; 95% CI 1.7-5.8). Totally 81 patients (14.7%) had sentinel headache within the last week before stroke and one control. Attacks of arrythmia during seven days before stroke were significantly associated with sentinel headache (p = 0.04, OR 2.3; 95% CI 1.1-4.8). Conclusions: A new type of headache and a previous kind of headache with altered characteristics during one week before stroke are significantly more prevalent than in controls. These headaches represent sentinel headaches. Sudden onset of such headaches should alarm about stroke. © 2020 The Author(s)

Diagnostic Criteria for Acute Headache Attributed to Ischemic Stroke and for Sentinel Headache Before Ischemic Stroke

Background: Defining the relationship between a headache and stroke is essential. The current diagnostic criteria of the ICHD-3 for acute headache attributed to ischemic stroke are based primarily on the opinion of experts rather than on published clinical evidence based on extensive case-control studies in patients with first-ever stroke. Diagnostic criteria for sentinel headache before ischemic stroke do not exist. The present study aimed to develop explicit diagnostic criteria for headache attributed to ischemic stroke and for sentinel headache. Methods: This prospective case-control study included 550 patients (mean age 63.1, 54% males) with first-ever ischemic stroke and 192 control patients (mean age 58.7, 36% males) admitted to the emergency room without any acute neurological deficits or severe disorders. Standardized semi-structured interview forms were used to evaluate past and present headaches during face-to-face interviews by a neurologist on admission to the emergency room in both groups of patients. All headaches were diagnosed according to the ICHD-3. We tabulated the onset of different headaches before a first-ever ischemic stroke and at the time of onset of stroke. We divided them into three groups: a new type of headache, the previous headache with altered characteristics and previous unaltered headaches. The same was done for headaches in control patients within one week before admission to the hospital and at the time of entry. These data were used to create and test diagnostic criteria for acute headache attributed to stroke and sentinel headache. Results: Our previous studies showed that headache at onset of ischemic stroke was present in 82 (14.9%) of 550 patients, and 81 (14.7%) patients had sentinel headache within the last week before a stroke. Only 60% of the headaches at stroke onset fulfilled the diagnostic criteria of ICHD-3. Therefore, we proposed alternative criteria with a sensitivity of 100% and specificity of 97%. Besides, we developed diagnostic criteria for sentinel headache for the first time with a specificity of 98% and a sensitivity of 100%. Conclusions: We suggest alternative diagnostic criteria for acute headache attributed to ischemic stroke and new diagnostic criteria for sentinel headache with high sensitivity and specificity. © 2022, The Author(s)

Persistent headache after first-ever ischemic stroke: clinical characteristics and factors associated with its development

Background: It is poorly described how often headache attributed to stroke continues for more than 3 months, i.e. fulfils the criteria for persistent headache attributed to ischemic stroke. Our aims were: 1) to determine the incidence of persistent headache attributed to past first-ever ischemic stroke (International headache society categories 6.1.1.2); 2) to describe their characteristics and acute treatment; 3) to analyse the prevalence of medication overuse headache in patients with persistent headache after stroke; 4) to evaluate factors associated with the development of persistent headache after stroke. Methods: The study population consisted of 550 patients (mean age 63.1, 54% males) with first-ever ischemic stroke, among them 529 patients were followed up at least three months after stroke. Standardized semi-structured interview forms were used to evaluate these headaches during professional face-to-face interviews at stroke onset and telephone interviews at 3 months. Results: At three months, 61 patients (30 women and 31 men, the mean age 60.0) of 529 (11.5%) follow-up patients had a headache after stroke: 34 had a new type of headache, 21 had a headache with altered characteristics and 6 patients had a headache without any changes. Therefore 55 (10.4%) patients had a persistent headache attributed to ischemic stroke. Their clinical features included: less severity of accompanying symptoms, slowly decreasing frequency and development of medication overuse headache in one-third of the patients. The following factors were associated with these headaches: lack of sleep (29.1%, p = 0.009; OR 2.3; 95% CI 1.2–4.3), infarct in cerebellum (18.2%, p = 0.003; OR 3.0; 95% CI 1.4–6.6), stroke of undetermined etiology (50.9%, p = 0.003; OR 2.3; 95% CI 1.3–4.1), less than 8 points by NIHSS score (90.9%, p = 0.007; OR 3.4; 95% CI 1.4–8.6) and low prevalence of large-artery atherosclerosis (12.7%, p = 0.006; OR 0.3; 95% CI 0.2–0.80). Conclusion: Persistent headache attributed to ischemic stroke is not rare and frequently leads to medication overuse. The problem is often neglected because of other serious consequences of stroke but actually, it has a considerable impact on quality of life. It should be a focus of interest in the follow-up of stroke patients. © 2022, The Author(s).We thank Tatiana S. Tsypushkina and Polina A. Philimonova for the help with data collection. None

ELECTROMECHANICAL MODEL OF THE LEFT VENTRICLE OF THE HUMAN HEART

We developed a mathematical model of the left ventricle electromechanical function of the human heart. We examine one full cycle of the left ventricle contraction with various parameters of the speed of the wave of excitation and spin of the myocardial fibers in the ventricle wall

Correlation between cells blood aggregation and peripheral blood cells lymphocyte aberration in brain glioma patients

The correlation between the peripheral blood cells aggregation level measured by surface plasmon resonance method (SPR), and chromosomal abberations of peripheral blood lymphocytes in brain malignant gliomas patients was investigated. It was found, that results of SPR in patients with brain gliomas were significantly lower than in healthy persons and gradually decreased with increasing of the gliomas malignancy grade. It was shown that decreasing of SPR data correlate with the statistically significant increase of chromosomal aberration in peripheral blood lymphocytes in glioma patients