scholarly journals ECG Electrode Placements for Magnetohydrodynamic Voltage Suppression

2018 ◽  
Vol 4 (7) ◽  
pp. 94
Author(s):  
T. Gregory ◽  
John Oshinski ◽  
Zion Tse
Keyword(s):  
Healthy Subjects ◽  
Human Subjects ◽  
Vector Model ◽  
Electrode Placement ◽  
Qrs Complex ◽  
Ecg Signals ◽  
Qrs Complex Detection ◽  
Group 2 ◽  
Magnetic Resonance Imaging Mri ◽  
Group 1

This study aims to investigate a set of electrocardiogram (ECG) electrode lead locations to improve the quality of four-lead ECG signals acquired during magnetic resonance imaging (MRI). This was achieved by identifying electrode placements that minimized the amount of induced magnetohydrodynamic voltages (VMHD) in the ECG signals. Reducing VMHD can improve the accuracy of QRS complex detection in ECG as well as heartbeat synchronization between MRI and ECG during the acquisition of cardiac cine. A vector model based on thoracic geometry was developed to predict induced VMHD and to optimize four-lead ECG electrode placement for the purposes of improved MRI gating. Four human subjects were recruited for vector model establishment (Group 1), and five human subjects were recruited for validation of VMHD reduction in the proposed four-lead ECG (Group 2). The vector model was established using 12-lead ECG data recorded from Group 1 of four healthy subjects at 3 Tesla, and a gradient descent optimization routine was utilized to predict optimal four-lead ECG placement based on VMHD vector alignment. The optimized four-lead ECG was then validated in Group 2 of five healthy subjects by comparing the standard and proposed lead placements. A 43.41% reduction in VMHD was observed in ECGs using the proposed electrode placement, and the QRS complex was preserved. A VMHD-minimized electrode placement for four-lead ECG gating was presented and shown to reduce induced magnetohydrodynamic (MHD) signals, potentially allowing for improved cardiac MRI physiological monitoring.

scholarly journals Different lead locations guided by fluoroscopy and ECG parameters and their effect on patients functional status

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Mohamed MesbahTahaHassanin ◽  
Ahmad ShafieAmmar ◽  
Radwa M. Abdullah ◽  
Mohammad Hassan Khedr
Keyword(s):  
Functional Capacity ◽  
Systolic Function ◽  
Left Ventricular ◽  
Left Ventricular Dyssynchrony ◽  
Qrs Complex ◽  
Significant Difference ◽  
Septal Pacing ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Abstract Background Right ventricular apical pacing with the resultant left ventricular dyssynchrony often leads to depressed systolic function and heart failure. This study aimed at investigating the relation between various septal locations guided by ECG and fluoroscopy and the intermediate term functional capacity of the patients. Results Fifty patients who received a single lead pacemaker with assumed > 90% pacemaker dependency. Patients were randomized according to RV pacing site RV into group 1 “high septum” (n = 15), group 2 “mid septum” (n = 25), and group 3 “low septum” (n = 10) using QRS vector and duration as well as fluoroscopic parameters. Their clinical status was assessed 6 months after device implementation using 6-min walk test (6MWT). The study showed that paced QRS complex duration itself has no significant difference between the different septal pacing locations (P-value 0.675), although its combination with the paced QRS complex vector can signify the optimal pacing site and 6MWT showed a significant difference among the groups in favor of group 1; group 1 (413.3 ± 148.5), group 2 (359.8 ± 124.6), and group 3 (276.0 ± 98.5) P value 0.04. Conclusion There was a significant difference found between the three septal pacing sites concerning the patient functional capacity with superiority of high septal location. By contrast, different septal sites showed no significant difference of the paced QRS complex duration. To optimize the pacing site in the septum, assessment of the paced QRS vector in leads I and III is of a great benefit especially when combined with paced QRS complex duration assessment.

Electrical Activity from the Superior Pharyngeal Constrictor During Reflexive and Nonreflexive Tasks

1989 ◽  
Vol 32 (4) ◽  
pp. 749-754 ◽  
Author(s):  
Adrienne L. Perlman ◽  
Erich S. Luschei ◽  
Charles E. Du Mond
Keyword(s):  
Electrical Activity ◽  
Healthy Subjects ◽  
General Trend ◽  
Human Subjects ◽  
Electrode Placement ◽  
Emg Activity ◽  
Constrictor Muscle ◽  
Natural Logarithm ◽  
Quantitative Manner ◽  
Normal Human

The purpose of this investigation was to determine, in a quantitative manner, which, if any, nonswallowing tasks produce significant levels of activation in the superior pharyngeal constrictor muscle of normal human subjects. Bipolar hooked wire electrodes were inserted in the superior pharyngeal constrictor muscle of 15 healthy subjects. Electrode placement was controlled. Each subject performed two reflexive tasks, six voluntary tasks requiring phonation, and four nonspeech voluntary tasks. The electromyogram (EMG) was rectified and integrated. The resulting number was then transformed by taking its natural logarithm. An ANOVA was performed and a linear model was estimated. The magnitude of the EMG activity was related to the location of the electrodes. The largest values were recorded in the lateral-superior placement, followed by the lateral-inferior, medial-inferior and medial-superior. The superior pharyngeal contrictor was found to be a muscle activated primarily during reflexive activity. There was a general trend in the amplitude of EMG activity in relationship to task. Swallowing produced the greatest amount of activity and a gag produced about 60% of the activity produced by the swallow. Two tasks, production of the work /hk/ in which the phoneme /k/ was stressed, and a "modified Valsalva," which was actually a hard /k/ held for several seconds, produced the next greatest level of EMG.

scholarly journals Medial plantar nerve: normative parameters of an electroneuromyographic study in adults

2021 ◽  
Vol 11 (2) ◽  
pp. 28-34
Author(s):  
D. A. Grishina ◽  
N. A. Suponeva
Keyword(s):  
Statistical Analysis ◽  
Healthy Subjects ◽  
Tibial Nerve ◽  
Age Group ◽  
Research Practice ◽  
Healthy Individuals ◽  
Medial Plantar Nerve ◽  
Comparative Statistical Analysis ◽  
Group 2 ◽  
Group 1

Background. The study of the sensitive portion of the medial plantar nerve is relevant not only in the examination of patients with tibial nerve mononeuropathy or its branches, but also in the diagnosis of polyneuropathies.Objective: to analyze the normative parameters of the sensory potential recorded during the study of the medial plantar nerve by the orthodromic method in healthy adults.Materials and methods. 126 sensitive fibers of the medial plantar nerves were studied on the Dantec Keypoint G4 device (Denmark) in 63 healthy individuals (31 men and 32 women; age from 20 to 80 years). 3 groups were identified taking into account age: group 1 included healthy people aged 20 to 39 years (n = 23); group 2 consisted of people aged 40 to 60 years (n = 20); and 3 – older than 60 years (n = 20). The parameters of the sensory potential of the medial plantar nerve are analyzed.Results. The sensory potential in the study of the sensitive portion of the medial plantar nerve was registered in all 126 healthy subjects. Comparative statistical analysis did not demonstrate significant differences between groups 1–3 in the values of such parameters of the sensory potential as the latency of the onset, the duration of the negative phase and the rate of propagation of excitation. At the same time, in groups 2 and 3, the magnitude of the amplitude from peak to peak of the sensory potential was significantly lower compared to group 1, and averaged 8.92 and 7.86 MV, respectively.Conclusion. Knowledge of the regulatory parameters will allow expanding the use of electroneuromyography of the sensitive portion of the medial plantar nerve in clinical and research practice.

scholarly journals Inter-Patient CNN-LSTM for QRS Complex Detection in Noisy ECG Signals

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 169359-169370 ◽  
Author(s):  
Brosnan Yuen ◽  
Xiaodai Dong ◽  
Tao Lu
Keyword(s):  
Qrs Complex ◽  
Ecg Signals ◽  
Qrs Complex Detection ◽  
Complex Detection

Determination of alpha 2-macroglobulin-trypsin complex with a new synthetic substrate.

1989 ◽  
Vol 35 (11) ◽  
pp. 2169-2172 ◽  
Author(s):  
K Kuroiwa ◽  
S Nakatsuyama ◽  
K Katayama ◽  
T Nagasawa
Keyword(s):  
Healthy Subjects ◽  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Pancreatic Disease ◽  
Chromogenic Substrate ◽  
Standard Curve ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Abstract We have developed a colorimetric assay for quantifying alpha 2-macroglobulin-trypsin complex (alpha 2M-TRY) in human serum, based on use of a new chromogenic substrate D-gamma-tert-butyloxy-Glu-Gly-Arg-3-carboxy-4-hydroxyanilide dihydrochloride (PS-3001). Within-run CVs by this assay were 4.76%, 1.57%, and 0.83% for trypsin complex concentrations of 3.1, 12.2, and 48.1 U/L, respectively (n = 10 each). Between-day CVs were 5.38%, 3.12%, and 2.20% at each concentration, respectively (n = 7). Mean analytical recoveries of alpha 2M-TRY added to serum were 100%, 105%, and 101% for 9.2, 15.1, and 46.3 U/L, respectively (n = 2). The standard curve obtained was linear up to 330 U/L. We applied this method to the study of alpha 2M-TRY activity in sera from 97 healthy subjects (group 1), from 27 patients with acute pancreatitis (group 2), and from 25 patients with other chylopoietic diseases (group 3); results ranged from 0 to 1.2 U/L (mean = 0.5, SD = 0.3), from 1.2 to 77.4 U/L (mean = 14.6, SD = 19.0), and from 0 to 1.3 U/L (mean = 0.4, SD = 0.3), respectively. Concentrations of enzymatically active alpha 2M-TRY were significantly greater in sera from group 2 than in groups 1 and 3. The determination of serum alpha 2M-TRY activity by this simple, rapid, colorimetric method may be useful for the diagnosis and evaluation of pancreatic disease.

scholarly journals Central nervous system metastases from breast carcinoma: a clinical and laboratorial study in 47 patients

1998 ◽  
Vol 56 (2) ◽  
pp. 188-192 ◽  
Author(s):  
ALUÍZIO B.B. MACHADO ◽  
ALEXANDRE A.C. MACHADO ◽  
JOSÉ ALEXANDRE M. BARBUTO ◽  
RICARDO M. DE OLIVEIRA
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Diagnostic Methods ◽  
Motor Deficits ◽  
Time Interval ◽  
Central Nervous System Metastases ◽  
Group 2 ◽  
Magnetic Resonance Imaging Mri ◽  
Csf Examination ◽  
Group 1

In this retrospective study, 47 patients with clinical diagnosis of central nervous system metastases of breast cancer were evaluated by computerized tomography (CT), magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) examination. The patients were divided in 2 groups: 1, without leptomeningeal neoplasm and 2, with leptomeningeal neoplasm. In the group 2, the time interval between the primary disease and the central nervous system metastasis as well as the survival time were shorter than in group 1 (40 and 4.3 months in group 2 versus 57 and 10 months respectively, in group 1). In both groups the most common neurological symptoms and signs were intracranial hypertension and motor deficits. The most sensitive diagnostic methods were CT and MRI in group 1, and the CSF examination in group 2. The use of the tumor markers CEA and CA-15.3 in the routine examination of CSF showed promising results, mainly in leptomeningeal forms.

scholarly journals Screening for MELAS mutations in young patients with stroke of undetermined origin

2007 ◽  
Vol 65 (2b) ◽  
pp. 371-376 ◽  
Author(s):  
Adriana Bastos Conforto ◽  
Fabio Iuji Yamamoto ◽  
Sueli Mieko Oba-Shinjo ◽  
Julio Guy C. Pinto ◽  
Maurício Hoshino ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Healthy Subjects ◽  
Young Patients ◽  
Clinical Findings ◽  
Melas Syndrome ◽  
Mitochondrial Mutations ◽  
A3243g Mutation ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

PURPOSE: It has been suggested that mitochondrial disease may be responsible for a substantial proportion of strokes of indetermined origin. We have preliminarily screened for MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) mutations in young patients with cryptogenic strokes. METHOD: The mitochondrial mutations A3243G and T3271C were investigated in 38 subjects aged less than 46 years. Group 1: 15 patients with cryptogenic strokes; Group 2: 3 patients with diagnosis of MELAS syndrome, including stroke-like episodes; Group 3: 20 healthy subjects. RESULTS: The A3243G mutation was absent in all subjects in Groups 1 and 3 but was present in all subjects in Group 2. CONCLUSION: Our results do not support screening for these mutations to diagnose oligosymptomatic forms of MELAS in cryptogenic strokes in the absence of other features of the syndrome. We suggest that clinical findings should guide mitochondrial genetic testing.

scholarly journals Effect of Cycloplegia on Keratometric and Biometric Parameters in Keratoconus

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Nihat Polat ◽  
Abuzer Gunduz
Keyword(s):  
Axial Length ◽  
Healthy Subjects ◽  
Anterior Chamber Depth ◽  
Corneal Curvature ◽  
Corneal Surface ◽  
Biometric Parameters ◽  
Before And After ◽  
The Difference ◽  
Group 2 ◽  
Group 1

Purpose.To obtain information about effect of cycloplegia on keratometry and biometry in keratoconus.Methods.48 keratoconus (Group 1) and 52 healthy subjects (Group 2) were included in the study. We measured the flat meridian of the anterior corneal surface (K1), steep meridian of the anterior corneal surface (K2), lens thickness (LT), anterior chamber depth (ACD), and axial length (AL) using the Lenstar LS 900 before and after cycloplegia.Results.The median K1 in Group 1 was 45.64 D before and 45.42 D after cycloplegia, and the difference was statistically significant (P<0.05). The median K2 in Group 1 was 50.96 D before and 50.17 D after cycloplegia, and the difference was significant (P<0.05). The median K1 and K2 in Group 2 were 42.84 and 44.49 D, respectively, before cycloplegia, and 42.84 and 44.56 D after cycloplegia, and the differences were not statistically significant (allP>0.05). There were significant differences in SE, LT, ACD, and RLP between before and after cycloplegia in either Group 1 (allP<0.05) or Group 2 (allP<0.05). There were not statistically significant differences in AL between before cycloplegia and after cycloplegia in either Group 1 (P=0.533) or group 2 (P=0.529).Conclusions.Flattened corneal curvature and increase in ACD following cycloplegia in keratoconus patients were detected.

Conspicuity Advantage of Fluorescent Color Targets in the Field

1996 ◽  
Vol 40 (18) ◽  
pp. 915-918 ◽  
Author(s):  
Helmut T. Zwahlen ◽  
Thomas Schnell
Keyword(s):  
Healthy Subjects ◽  
Visual Detection ◽  
Radial Distance ◽  
Target Size ◽  
Large Target ◽  
Yellow Orange ◽  
Green Background ◽  
Group 2 ◽  
Group 1 ◽  
Detection And Recognition

Daytime conspicuity of fluorescent and non-fluorescent color targets was investigated in the field against a green background in terms of visual detection and recognition, as a function of the peripheral angle and the target size. Two groups of 9 young, healthy subjects each were used. The colors white, blue, green, red, fluorescent red, fluorescent yellow-green, yellow, fluorescent yellow, orange, fluorescent orange were presented for 2 seconds at a radial distance of 30m under the peripheral viewing angles of 10°, 20°, 30° for group 1, and 30°, 40°, 50° for group 2. The target sizes 0.076m x 0.152m, 0.114m x 0.229m, and 0.152m x 0.305m were used in group 1, and 0.114m x 0.229m, 0.152m x 0.305m, and 0.229m x 0.457m were used in group 2. Fluorescent color targets (especially fluorescent yellow-green) were better peripherally detected than the non-fluorescent color targets. White, blue, and green were better recognized but exhibited relatively poor peripheral conspicuity. Therefore it appears that if one wants to maximize the peripheral daytime conspicuity, both highly conspicuous fluorescent colors along with a fairly large target size should be selected. Such a target configuration may for example be needed to attract a driver's attention in situations where a target is located in an observer's visual periphery (peripheral angle > 20°), for example a target approaching a driver at an intersection from a left or right side street.

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