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MedLife Clinics 2022There is a need to accurately identify pregnant women at risk for preterm birth as early as possible. Recent developments in technology enable the recording of uterine...
BACKGROUND
There is a need to accurately identify pregnant women at risk for preterm birth as early as possible. Recent developments in technology enable the recording of uterine electrical activity (electrohysterogram) from the anterior abdominal wall in a non-invasive way.
OBJECTIVE
To investigate whether uterine activity recorded under resting conditions at a gestational age of 34 weeks could identify a risk of preterm birth.
STUDY DESIGN
A commercial antenatal holter device with its dedicated software was used to record and store raw data of the maternal and fetal electrocardiograms and uterine activity for the Safe Passage Study. Uterine activity was recorded under resting conditions from 34 weeks' gestation in epochs of 250 ms (millisecond) for at least 30 min. From this database the raw data, recorded at a mean gestational age of 34 weeks, of 50 women who had preterm deliveries were selected for comparison with data of women who had term deliveries. Mean uterine activity, expressed in microvolt (μV)/epoch, was used for the comparison.
RESULTS
After exclusion of 25 participants where labour was induced or augmented and another three for other reasons, 36 remained in each group. The participants in each group were comparable in respect of maternal age, gravidity, parity, gestational age at recruitment and duration of recording. Uterine activity in the preterm group (60.3 μV/epoch) differed significantly (p<0.01) from that of the comparison group (52.4 μV/epoch). Using a cut-off point of 52.3 μV/epoch as obtained from receiver operator characteristic curves (area under the curve 0.72), the sensitivity and specificity of identifying risks of preterm labour were 81% and 50% respectively.
CONCLUSION
Results of this small study are promising but need to be confirmed in larger studies and preferably at earlier gestational age.
PubMed: 36660227
DOI: No ID Found -
Clinical Autonomic Research : Official... Feb 2023Drug-induced type I Brugada syndrome (BrS) is associated with a ventricular arrhythmia (VA) rate of 1 case per 100 person-years. This study aims to evaluate changes in...
PURPOSE
Drug-induced type I Brugada syndrome (BrS) is associated with a ventricular arrhythmia (VA) rate of 1 case per 100 person-years. This study aims to evaluate changes in electrocardiographic (ECG) parameters such as microvolt T wave alternans (mTWA) and heart rate variability (HRV) at baseline and during ajmaline testing for BrS diagnosis.
METHODS
Consecutive patients diagnosed with BrS during ajmaline testing with 5-year follow-up were included in this study. For comparison, a negative ajmaline control group and an isoproterenol control group were also included. ECG recordings during ajmaline or isoproterenol test were divided in two timeframes from which ECG parameters were calculated: a 5-min baseline timeframe and a 5-min drug timeframe.
RESULTS
A total of 308 patients with BrS were included, 22 (0.7%) of which suffered VAs during follow-up. One hundred patients were included in both isoproterenol and negative ajmaline control groups. At baseline, there was no difference in ECG parameters between control groups and patients with BrS, nor between BrS with and without VAs. During ajmaline testing, BrS with VAs presented longer QRS duration [159 ± 34 ms versus 138 (122-155) ms, p = 0.006], higher maximum mTWA [33.8 (14.0-114) µV versus 8.00 (3.67-28.2) µV, p = 0.001], and lower power in low frequency band [25.6 (5.8-53.8) ms versus 129.5 (52.7-286) ms, p < 0.0001] when compared to BrS without VAs.
CONCLUSIONS
Ajmaline induced important HRV changes similar to those observed during isoproterenol. Increased mTWA was observed only in patients with BrS. BrS with VAs during follow-up presented worse changes during ajmaline test, including lower LF power and higher maximum mTWA which were independent predictors of events.
Topics: Humans; Ajmaline; Brugada Syndrome; Heart Rate; Isoproterenol; Arrhythmias, Cardiac; Electrocardiography; Prognosis
PubMed: 36645559
DOI: 10.1007/s10286-023-00922-4 -
Scientific Reports Dec 2022Sudden cardiac death is impactful. There has been an increase in the search for tools capable of identifying individuals who are most susceptible, such as the microvolt...
Sudden cardiac death is impactful. There has been an increase in the search for tools capable of identifying individuals who are most susceptible, such as the microvolt T-wave alternans. This study aims to analyze the applicability of the modified moving average methodology to obtain the microvolt T-wave alternans using treadmill specific protocols. Medical records of patients during the period August 2006-December 2014 were retrospectively analyzed. Five hundred and thirty nine exams were then included, divided into groups according to the protocol and updating factor used: Ellestad factor 8 or 32, Naughton factor 8 or 32. The topics for analysis were the alternans behavior, noise and confirmation according to the groups of leads analyzed (frontal, transversal and orthogonal planes). The greater microvolt T-wave alternans was found during the stress phase in most of the tests. Group Naughton 8 presented lower noise in this phase for the transverse and orthogonal planes (p = 0.0082 and p < 0.0001), with greater confirmation of frontal and orthogonal planes in comparison with group Ellestad 8 (p = 0.0002 and 0.0008). The results indicate the viability of simultaneous performance of the stress test and measurement of the T wave alternans with Naughton protocol with 1/8 updating factor.
Topics: Humans; Exercise Test; Retrospective Studies; Factor VIII; Arrhythmias, Cardiac; Death, Sudden, Cardiac; Electrocardiography
PubMed: 36575194
DOI: 10.1038/s41598-022-26535-x -
Sensors (Basel, Switzerland) Dec 2022In recent years, tremendous advancements have been made in various technologies such as far-infrared, low-frequency Raman, and two-dimensional (2D) Raman terahertz (THz)... (Review)
Review
In recent years, tremendous advancements have been made in various technologies such as far-infrared, low-frequency Raman, and two-dimensional (2D) Raman terahertz (THz) spectroscopies. A coherent method has emerged from numerous experimental and theoretical investigations of molecular dynamics in liquids by comparing linear and non-linear spectroscopic techniques. Intermolecular hydrogen bond vibration, molecular reorientation motion, and interaction between molecule/ionic solute and hydrogen bonds have been demonstrated to occur in the THz region, which are closely related to their physical/chemical properties and structural dynamics. However, precise probing of various modes of motion is difficult because of the complexity of the collective and cooperative motion of molecules and spectral overlap of related modes. With the development of THz science and technology, current state-of-the-art THz sources can generate pulsed electric fields with peak intensities of the order of microvolts per centimeter (MV/cm). Such strong fields enable the use of THz waves as the light source for non-linear polarization of the medium and in turn leads to the development of the emerging THz Kerr effect (TKE) technique. Many low-frequency molecular motions, such as the collective directional motion of molecules and cooperative motion under the constraint of weak intermolecular interactions, are resonantly excited by an intense THz electric field. Thus, the TKE technique provides an interesting prospect for investigating low-frequency dynamics of different media. In view of this, this paper first summarizes the research work on TKE spectroscopy by taking a solid material without low-frequency molecular motions as an example. Starting from the principle of TKE technology and its application in investigating the properties of solid matter, we have explored the low-frequency molecular dynamics of liquid water and aqueous solutions using TKE. Liquid water is a core of life and possesses many extraordinary physical and biochemical properties. The hydrogen bond network plays a crucial role in these properties and is the main reason for its various kinetic and thermodynamic properties, which differ from those of other liquids. However, the structure of the hydrogen bond network between water and solutes is not well known. Therefore, evaluating the hydrogen bond-related kinetic properties of liquid water is important.
Topics: Hydrogen Bonding; Vibration; Molecular Dynamics Simulation; Water; Spectrum Analysis, Raman; Solutions
PubMed: 36502125
DOI: 10.3390/s22239424 -
Science Translational Medicine Sep 2022Chronic nausea and vomiting syndromes (NVSs) are prevalent and debilitating disorders. Putative mechanisms include gastric neuromuscular disease and dysregulation of...
Chronic nausea and vomiting syndromes (NVSs) are prevalent and debilitating disorders. Putative mechanisms include gastric neuromuscular disease and dysregulation of brain-gut interaction, but clinical tests for objectively defining gastric motor function are lacking. A medical device enabling noninvasive body surface gastric mapping (BSGM) was developed and applied to evaluate NVS pathophysiology. BSGM was performed in 43 patients with NVS and 43 matched controls using Gastric Alimetry (Alimetry), a conformable high-resolution array (8 × 8 electrodes; 20-mm interelectrode spacing), wearable reader, and validated symptom-logging app. Continuous measurement encompassed a fasting baseline (30 minutes), 482-kilocalorie meal, and 4-hour postprandial recording, followed by spectral and spatial biomarker analyses. Meal responses were impaired in NVS, with reduced amplitudes compared to controls (median, 23.3 microvolts versus 38.0 microvolts, < 0.001), impaired fed-fasting power ratios (1.1 versus 1.6, = 0.02), and disorganized slow waves (spatial frequency stability, 13.6 versus 49.5; < 0.001). Two distinct NVS subgroups were evident with indistinguishable symptoms (all > 0.05). Most patients (62%) had normal BSGM studies with increased psychological comorbidities (43.5% versus 7.7%; = 0.03) and anxiety scores (median, 16.5 versus 13.0; = 0.035). A smaller subgroup (31%) had markedly abnormal BSGM, with biomarkers correlating with symptoms (nausea, pain, excessive fullness, early satiety, and bloating; all > 0.35, < 0.05). Patients with NVS share overlapping symptoms but comprise distinct underlying phenotypes as revealed by a BSGM device. These phenotypes correlate with symptoms, which should inform clinical management and therapeutic trial design.
Topics: Gastric Emptying; Humans; Nausea; Stomach; Syndrome; Vomiting
PubMed: 36130019
DOI: 10.1126/scitranslmed.abq3544 -
Annals of Noninvasive Electrocardiology... Jan 2023Despite early repolarization (ER) syndrome being usually considered benign, its association with severe/malignant ventricular arrhythmias (VA) was also reported....
Despite early repolarization (ER) syndrome being usually considered benign, its association with severe/malignant ventricular arrhythmias (VA) was also reported. Microvolt T-wave alternans (MTWA) is an electrocardiographic marker for the development of VA, but its role in ER syndrome remains unknown. A 90-second 6-lead electrocardiogram from an ER syndrome patient, acquired with the Kardia recorder, was analyzed by the enhanced adaptive matched filter for MTWA quantification. On average, MTWA was 50 μV, higher than what was previously observed on healthy subjects using the same method. In our ER syndrome patient, MTWA plays a potential role in VA development in ER syndrome.
Topics: Humans; Death, Sudden, Cardiac; Electrocardiography; Arrhythmias, Cardiac; Risk Assessment; Defibrillators, Implantable
PubMed: 36114698
DOI: 10.1111/anec.13005 -
Annual International Conference of the... Jul 2022Cardiac alternans has been associated with an increased propensity to lethal tachyarrhythmias such as ventricular tachycardia and fibrillation (VT/VF). Myocardial...
Cardiac alternans has been associated with an increased propensity to lethal tachyarrhythmias such as ventricular tachycardia and fibrillation (VT/VF). Myocardial infarction (MI), resulting from restricted oxygen supply to the heart, is a known substrate for VT/VF. Here, we investigate the utility of cardiac alternans as a predictor of tachyarrhythmias in a chronic MI ovine model. In-vivo electrophysiological studies were performed to assess the change in microvolt T-wave alternans (TWA) with induction of acute ischemia following coronary artery occlusion. 24-hour telemetry was performed in an ambulatory animal for 6 weeks to monitor the progression of TWA with chronic MI. At 6 weeks, ex-vivo optical mapping experiments were performed to assess the spatiotemporal evolution of alternans in sham (n=5) and chronic MI hearts (n=8). Our results demonstrate that chronic MI leads to significant electrophysiological changes in the cardiac substrate. Significant increase in TWA is observed post occlusion and a steady rise in alternans is seen with progression of chronic MI. Compared to sham, chronic MI hearts show significant presence of localized action potential amplitude alternans, which spatially evolve with an increase in pacing frequency. Clinical Relevance - Our results demonstrate that localized alternans underlie arrhythmogenesis in chronic MI hearts and microvolt TWA can serve as a biomarker of disease progression during chronic MI.
Topics: Animals; Arrhythmias, Cardiac; Biomarkers; Myocardial Infarction; Sheep; Sheep, Domestic; Tachycardia, Ventricular
PubMed: 36086483
DOI: 10.1109/EMBC48229.2022.9871496 -
Annual International Conference of the... Jul 2022Spontaneous muscular activities can be studied by simultaneous recordings of surface electromyography (sEMG) and diffusion-weighted magnetic resonance imaging (DW-MRI)....
Spontaneous muscular activities can be studied by simultaneous recordings of surface electromyography (sEMG) and diffusion-weighted magnetic resonance imaging (DW-MRI). For reliable assessment of the spontaneous activity rate in sEMG data during active MR imaging, it is necessary to have a decent gradient artifact (GA) correction algorithm enabling the detection of small spontaneous activities with an amplitude of few microvolts. In this work, a neural network with weak label annotations during the training process is utilized for enhanced correction of GA residuals in the sEMG recordings. Based on sEMG signal decomposition and class-activation maps from the neural network classification, the amount of GA residuals is iteratively decreased in the sEMG signal. This leads to a reduction of the false-positive rate in automated spontaneous activity detection. Quality of GA residual correction is therefore estimated by using a specialized second neural network model. Clinical relevance- This work establishes an improved GA residual correction for simultaneously recorded sEMG data during MRI to enhance the ability for small spontaneous activity detection.
Topics: Artifacts; Diffusion Magnetic Resonance Imaging; Electromyography; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Neural Networks, Computer; Signal Processing, Computer-Assisted
PubMed: 36085922
DOI: 10.1109/EMBC48229.2022.9871062 -
Cardiovascular Digital Health Journal Aug 2022Qualitative differences in 12-lead electrocardiograms (ECG) at onset have been reported in patients with takotsubo syndrome (TTS) and acute anterior myocardial...
BACKGROUND
Qualitative differences in 12-lead electrocardiograms (ECG) at onset have been reported in patients with takotsubo syndrome (TTS) and acute anterior myocardial infarction (Ant-AMI). We aimed to distinguish these diseases by machine learning (ML) approach of microvolt-level quantitative measurements.
METHODS
We enrolled 56 consecutive patients with sinus rhythm TTS (median age, 77 years; 16 men), and 1-to-1 random matching was performed based on age and sex of the patients. The ECG in the emergency room was evaluated using an automated system (ECAPs12c; Nihon-Koden). Statistical and ML predictive models for TTS were constructed using clinical features and ECG parameters.
RESULTS
Statistically significant differences were observed in 25 parameters; the V ST level at the J point (V STJ) showed the lowest value ( < .001). V STJ ≤+18 μV showed the highest accuracy for TTS (0.773). The highest area under the receiver operating characteristic curve (AUROC) was shown in the aVR ST level at 1/16th of the preceding R-R interval after the J point (aVR STmid: 0.727). Conversely, the light gradient boosting machine (model_LGBM) and extra tree classifier (model_ET) indicated higher accuracy (model_LGBM: 0.842, model_ET: 0.831) and AUROC (model_LGBM: 0.868, model_ET 0.896) than other statistical models. V STJ had high feature importance and Shapley additive explanation values in the 2 ML models.
CONCLUSION
ML applied to automated microvolt-level ECG measurements showed the possibility of distinguishing between TTS and Ant-AMI, which may be a clinically useful ECG-based discriminator.
PubMed: 36046427
DOI: 10.1016/j.cvdhj.2022.07.001 -
Clinical Neurophysiology : Official... Oct 2022Periods of low-amplitude electroencephalographic (EEG) signal (quiescence) are present during both anesthetic-induced burst suppression (BS) and postictal generalized...
OBJECTIVE
Periods of low-amplitude electroencephalographic (EEG) signal (quiescence) are present during both anesthetic-induced burst suppression (BS) and postictal generalized electroencephalographic suppression (PGES). PGES following generalized seizures induced by electroconvulsive therapy (ECT) has been previously linked to antidepressant response. The commonality of quiescence during both BS and PGES motivated trials to recapitulate the antidepressant effects of ECT using high doses of anesthetics. However, there have been no direct electrographic comparisons of these quiescent periods to address whether these are distinct entities.
METHODS
We compared periods of EEG quiescence recorded from two human studies: BS induced in 29 healthy adult volunteers by isoflurane general anesthesia and PGES in 11 patients undergoing right unilateral ECT for treatment-resistant depression. An automated algorithm allowed detection of EEG quiescence based on a 10-microvolt amplitude threshold. Spatial, spectral, and temporal analyses compared quiescent epochs during BS and PGES.
RESULTS
The median (interquartile range) voltage for quiescent periods during PGES was greater than during BS (1.81 (0.22) microvolts vs 1.22 (0.33) microvolts, p < 0.001). Relative power was greater for quiescence during PGES than BS for the 1-4 Hz delta band (p < 0.001), at the expense of power in the theta (4-8 Hz, p < 0.001), beta (13-30 Hz, p = 0.04) and gamma (30-70 Hz, p = 0.006) frequency bands. Topographic analyses revealed that amplitude across the scalp was consistently higher for quiescent periods during PGES than BS, whose voltage was within the noise floor.
CONCLUSIONS
Quiescent epochs during PGES and BS have distinct patterns of EEG signals across voltage, frequency, and spatial domains.
SIGNIFICANCE
Quiescent epochs during PGES and BS, important neurophysiological markers for clinical outcomes, are shown to have distinct voltage and frequency characteristics.
Topics: Adult; Algorithms; Electroconvulsive Therapy; Electroencephalography; Humans; Isoflurane; Seizures
PubMed: 36030576
DOI: 10.1016/j.clinph.2022.07.493