Interval Measurement Research Articles

Automatic measurement of stimulation to maximum negative dv/dt in V5 and V6 leads to confirm left bundle capture for conduction system pacing

Abstract Introduction Left bundle area conduction system pacing is obtained when the ventricular pacing lead is implanted into the right ventricular septum and captures the left bundle branch, demonstrated by right bundle branch morphology in the lead V1 and short stimulation to R-wave peak time (SRWPT) in leads V5 or V6. Manual measurements are challenging and result in significant variability. Maximum negative dv/dt in leads V5 and V6, occurring immediate after maximal lateral wall depolarization, represents the ideal measurement of synchronicity of left ventricular depolarization, as suggested by the guidelines. Objective To test feasibility of automatic algorithm to measure the maximum negative dV/dt in comparison to manual SRWPT measurement in V5 and V6. Method Data was collected from 7 patients with confirmed left bundle branch capture. Three trained operators manually measured SRWPT in leads V5 and V6 (Figure A). An algorithm capable of automatically measuring stimulation to maximum dv/dt was retrospectively applied to the same measured beats. Variability and correlation of measurements was compared between manual and automatic using the Bartlett Test for equal variance. Results In total, 137 individual beats were measured in the 2 leads by three operators resulting in 822 manual measurements. The mean variability of SRWPT in V5 and V6 was 2.9 ± 0.7 msec and 3.1 ± 1.1 msec, respectively (inter-operator correlation of 0.83). In contrast the stimulation to max negative dv/ dt mean variability in V5 and V6 was 1.3 ± 0.4 msec and 1.2 ± 0.5 msec, respectively (P < 0.001). The comparison of variation in measurement between manual and automatic measures are shown in a box and whisker plot in figure 2. Conclusion Manual measurement of SRWPT can be challenging resulting in higher variability compared to an automatic algorithm measuring max negative dv/dt. This study demonstrates the feasibility of automatic interval measurement in conduction system pacing; however, further studies are required to validate the reliability of such tool.Fig 1.Example ECG interval measurement

HV interval measure immediately before TAVI with SEV for predicting pacemaker implantation

Abstract Introduction Although improvements, new onset persistent disturbances in electrocardiogram (ECG) after transcatheter aortic valve implantation (TAVI) remains up to 34% at hospital discharge (1), needing permanent pacemaker implantation (PPM) in self-expanding valves (SEV) as high as 15-27% (2,3). In post TAVI scenario, European Society of Cardiology guidelines recommend an electrophyisiologic study centered in His-ventricular electrogram (HV) interval measure for assessing risk of progression to high auriculoventricular block (AVB), if abnormal a PPM is indicated (4,5). We aim to predict PPM through basal HV interval measurement prior TAVI with SEV. Furthermore, we aim to compare different current SEV with basal HV interval and the distinct rate of PPM before discharge. Methods and Results Single-center prospective cohort study, patients with severe aortic stenosis scheduled for TAVI, sinus rhythm at intervention day, without PPM or history of PPM indication were included. At time of TAVI, contralateral venous puncture to femoral arterial access was made, a tetrapolar catheter was advanced and placed at the septal aspect of tricuspid valve searching for His electrogram. A mobile polygraph was used to measure ECG parameters and HV interval before TAVI. Then, a tetrapolar catheter was advanced to ventricle to perform rapid stimulation as part of habitual valve implantation protocol. After procedure, we performed rhythm surveillance for at least >48-72 hours and based in electrical evolution one of three decisions was made: 1)PPM implant, 2)late post TAVI HV interval re-measure or 3)clinical daily ECG vigilance, if this last was normal, unchanged from basal or with new but stable conduction disturbances, discharge were indicated following ESC guidelines. A total of 41 patients were enrolled, median age 84±4 years, 24 females (54.5%), PR mean 198±42ms, QRS mean 112±30ms. 18 had a 1st degree AVB (40.9%) of whom 13 (72.5%) had a PR ˂240ms. EPS data showed prior HV interval mean of 55±9ms. A Mild abnormal HV interval (56-69ms) were seen in 21 patients (51.2%), of whom 12 had a narrow QRS. SEV implanted were 11 (25%) Medtronic CoreValve Evolut+, 5 (11.4%) Biosensors Allegra, 25 (56.8%) Abbott Navitor. Post TAVI procedure, 5 (12.2%) women and 8 (19.5%) men met criteria for PPM implantation before discharge. One woman was implanted 6 days after discharge due to high AVB (66ms HV interval prior TAVR). In a multivariate analysis including sex, age, PR, QRS and HV interval >55ms, valve type the RR (IC 95% 1.37-30.99) risk of PPM was 6.52 folds higher (p=0.019). Conclusions An HV interval >55ms before TAVI with SEV increases risk of PPM after TAVI and before hospital discharge. There was no difference in PPM implantation after TAVI between different SEV types in our center.

A novel formula to assess the QT interval in ventricular paced rhythm

Abstract Background QT interval measurement in the presence of right ventricular pacing (RVP) represents a clinical challenge due to altered ventricular activation resulting in a prolonged QT-interval. The aim of this study is to compare the QT interval in patients before and after ventricular pacing to develop a new formula for QT interval assessment in patients with RVP. Methods and results All patients presenting to our pacemaker clinic with single- or dual chamber device were included in this prospective observational study. Inclusion criteria were no permanent right ventricular stimulation, an intrinsic QRS interval of <120 ms, and ventricular rate >35 bpm and <150 bpm. Three 12-lead electrocardiograms were recorded for each patient: during intrinsic rhythm and 2 following an atrial paced and a ventricular paced QRS at the same rate. The intrinsic QRS and QT time/JT time (QTi/JTi) were measured during intrinsic and subsequent RVP. To obtain the formula, all measurements were performed on 100 patients (mean age 74 ± 11.3, male 33%) (RV apical lead 30% and non-apical lead 70%). Based on our measurements, a new formula QT (non-paced) = 139.23 + 0.55 xQT (paced) was derived. A population of 482 individuals (mean age 75.5±13.2 years (SD), 64% male) with permanent RV pacing were used as a validation group. The intrinsic QRS and QT time were measured during SR and subsequent RVP. To assess the relationship between the predicted QT with RVP and the measured QT without RVP, linear correlations analyses were performed. Our formula had a strong correlation with the irrespective QT without RVP (r=0.50) Conclusion We proposed a new simple formula to accurately estimate QT during RVP. This formula can be easily utilized in clinical practice. Figure 1: MAD characteristic value via plots stands for Median Absolute Difference (i.e. by how many ms the prediction is estimated on average). Figure 2: "Forest Plot" illustrates the correlation coefficients in the form of a forest plot. The dot r represents r and the bars the 95% confidence intervalsMAD characteristic value via plots standForest Plot" illustrates the correlation

The usefulness of QT interval measurement as a screening tool for cascade testing in asymptomatic patients at risk of long QT syndrome

Abstract Background Long QT syndrome (LQTS), an inherited arrhythmic syndrome, remains a public health concern with up to 3000 unexpected deaths in the US annually. A simple 12-lead ECG is the most easily accessible tool for initial screening. Purpose To describe the diagnostic utility of the standard QT correction techniques in 12-Lead ECGs, in a screening population of first-degree relatives of persons with LQTS of known genotype. Methods In this single centre study, data were included on consecutive patients undergoing cascade clinical and genetic testing for LQTS, who had a first degree relative with genotype-positive LQTS, from the years 2019 to 2022. Patient demographics, baseline ECG and genetic results were obtained. The QT interval was manually calculated between three independent readers using the tangent method and corrected using the 4 most commonly used formulae: Bazett (BQTc), Fridericia (FreQTc), Framingham (FraQTc) and Hodges (HQTc). The Mean QT was calculated by taking the average of four consecutive QT measurements in lead II or V5. The QT dispersion (QTd), was also calculated by using the formula: QTd = QT max – QT min. Results Data was available on 97 patients from 14 families. The mean age at screening was 44 years, and 51.5% were males. Two-thirds of patients were asymptomatic (n = 74, 76.3%). Fifteen patients had syncopal events. 72.2% (n = 70) of patients had a family history of arrhythmic death. After clinical screening and genotyping, 46.4% (n = 45) patients were gene positive for either KCNQ1 (75.5%) or KCNH2 (24.5%). Patients with prior syncope were more likely to be gene positive (72.7% vs 39.2%, p = 0.005). The 12-Lead ECG derived QTc result is listed in Table 1, with all correction modalities showing a higher corrected QT in the genotype-positive group (p <0.001). The diagnostic performance of BQTc was similar to that of the newer formulae (FreQTc, FraQTc and HQTc) when correcting for heart rate within the range of 60 – 100bpm as listed in Table 2. At a cut-off value of 440ms, BQTc formula had a sensitivity of 51% and a specificity of 84% for predicting genotype pathogenicity as listed in Table 3. The QT dispersion was higher in patients with KCNH2 compared to those with KCNQ1 (122msec, SD 30.5 vs 74.2 msec, SD 30.4, p value <0.001). Patients with KCNH2 were more likely to require an ICD (83.3% vs 16.7%, p <0.001). The mean Schwartz score in gene positive patient was 2.6 compared to 1.9 (p <0.003). Conclusion Formula correction of QT interval to heart rate had good overall diagnostic performance. Both FreQT and FraQT had high AUROC across different heart rates, though there was no statistically significant difference seen between correction formulae. The ECG remains a good preliminary screening tool method for identifying patients with increased risk LQTS in this population. Larger studies are needed to power for comparisons between QT correction methods.

Prediction of nonsustained ventricular tachycardia development by the analysis of premature ventricular complex-related intervals on 24-hour rhythm monitoring and testing a novel index

Abstract Introduction Ventricular tachycardia (VT) and ventricular fibrillation (VF) are life- threatening arrhythmias, with non-sustained ventricular tachycardia (NSVT) serving as a potential precursor. Identifying individuals at risk of NSVT is crucial for effective management and prevention of sudden cardiac death in high-risk patients. In daily clinical practice, premature ventricular complex (PVC) and sometimes NSVT are frequently detected on 24-hour ambulatory rhythm monitoring. Purpose In this study, we aimed to predict the development of NSVT by analyzing PVC morphology and intervals in 24- hour ambulatory rhythm monitorings. Methods A retrospective analysis of 24-hour ambulatory rhythm monitoring recordings from 2018 to 2023 was conducted. Inclusion criteria required clear measurement of PVC intervals, at least 100 PVC in the recording, and two preceding normal QRS beats. NSVT diagnosis was based on four consecutive PVC lasting <30 s and a rate >100/min. Various PVC-related parameters were analyzed, and new variables were derived. Statistical analysis included Mann-Whitney U tests and ROC analysis. Results The study included 202 patients, revealing significant differences in several VES temporal variables between groups with only PVC (Group I) and PVC with NSVT (Group II). Notably, Age-Adjusted Sum of Intervals Index (AASI Index-(100 x [(Tp-to- QRSvpa)+(coupling time)+(Qtc1)]/age), long coupling times, extended Tp-to-QRSvpaintervals, and prolonged Tpe-vpa intervals were associated with NSVT development. Age played a pivotal role in predicting NSVT when integrated into a specific variable AASI index. The optimal cut-off value was 4.21, with 84% sensitivity and specificity. Conclusion The study suggests that ventricular arrhythmias may be predicted using temporal parameters of PVC, especially when age is included as a modifier. The AASI index calculated on a PVC and preceeding two normal beats on 24-hour ambulatory rhythm monitoring seems to be promising parameter. These findings hold potential for future development of artificial intelligence-based algorithms for use in any PVC to identify at-risk patient groups, provided larger datasets are utilized to refine predictive models.Variables included in the analysis for cDefinitions of variables and ROC curve

Comparison between smartphone 6-lead ECGs and 12-lead ECGs in athletes

Abstract Introduction Athletes occasionally experience transient arrythmias that are difficult to capture using traditional methods. Smartphone electrocardiogram (ECG) technology presents an innovative method of capturing transient arrythmias. A 6-lead (6L) smartphone device that measures leads I, II, III, aVR, aVL, and aVF, has been shown to be accurate in some populations but has limited evidence in athletes. A previous pilot study comparing 6L with 12L readings in athletes showed good correlations. Purpose To assess the accuracy of the 6L device in athletes by comparing the 6L with a 12-lead (12L) ECG in a larger sample size under real-world conditions. Methods From 2020-2023, athletes (n=217, mean age 18.0±3.8 years, 40% female) had a resting supine 12L ECG as part of cardiac screening and a seated 30s 6L reading within 2 hours of the 12L. Manual measurements of RR, QT, PR intervals, and QRS duration in the 6L and 12L ECGs were completed by a cardiologist using EPS Digital Calipers in lead II. A subset (n=30) was measured by 4 expert cardiologists and the mean was taken. Each measurement was calculated as an average of at least 6 consecutive beats in the 6L and 12L. Bland-Altman analysis was used to assess the quantitative agreement between heart rate (HR), QTc interval (Bazett), PR interval and QRS duration in the 6L and 12L. ECGs were analysed for agreement of QRS axis (normal, left and right axis deviation defined by the International Criteria for Athlete ECG Interpretation[1]). Results The 6L readings for HR were 5.0±11.0bpm faster than the 12L; 6L readings for other measurements were shorter than the 12L. QTc had the largest difference, with the 6L on average 14.2±27.4ms shorter than the 12L reading. For QTc, 5.5% of readings were >60ms different, mostly due to baseline interference in the 6L traces. PR intervals were 13.9±16.3ms shorter in the 6L than the 12L. QRS duration measurements were similar, with 6L readings being 0.8±10.2ms shorter than the 12L reading. There was 96.8% agreement on QRS axis classification between 6L and 12L. Conclusion The 6L readings had fair agreement with the 12L ECG, although the standard deviations were higher than measured in the pilot study, suggesting less consistent accuracy of the 6L. Most 6L measures (excluding HR) were slightly shorter than the 12L, consistent with studies in other populations. QRS axis categories were very similar. Given the change from supine to seated, it is unsurprising that HR was higher in the 6L. Our previous work showed good correlation between 6L and 12L readings and excellent utility of the portable 6L device for detecting transient arrhythmias in athletes. This larger study confirms most of those findings but adds caution that baseline interference is not uncommon in real-world 6L readings, meaning that QTc may be difficult to accurately measure.

Beat-to-beat measurement of R-wave peak time for left bundle branch area pacing: man versus machine using a novel automated algorithm

Abstract Background Assessment of stimulation spike to R-wave peak time (RWPT) in V6 and in aVL, and V6-V1 interpreak interval, may be used to evaluate presence of conduction system capture during left bundle branch area pacing (LBBAP). This is performed by manual measurements which is tedious and requires a skilled operator to limit variability in the measurements. Automatic beat-to-beat measurement of these intervals may streamline workflow during implantation, but such an algorithm has never been tested so far. Purpose To test the feasibility of performing beat-to-beat automatic measurement of RWPT using an algorithm designed to measure the interval between the stimulation spike and the peak positive voltage, and to compare the results with manual measurements. Methods ECG recordings from 50 patients (28% female, mean age 81.5 ± 9.0 years) undergoing LBBAP implantation were evaluated on a electrophysiology recording system by manually measuring RWPT in V6 and in aVL and the V6-V1 interpeak intervals . A single operator performed offline measurements on 10 consecutive beats in each patient. The same beats were subjected to the same measurements using an automatic algorithm after signal conditioning in a novel EP recording System. The correlation between manual and automatic measurements was calculated. Variability of the measurements (evaluated by standard deviation) in the 10 consecutive beats was also compared. Results Of the 500 beats measured, 3 were excluded due to obvious morphological differences affecting the interval measurement (e.g. due to fusion beats). The algorithm was unable to make a measurement in V6 in 20 beats and manual assessment of aVL was not possible in one patient, meaning that 1461/1500 (97.4%) measurements were compared between the manual and automatic methods. The results are shown in the figure. There was excellent correlation between manual and automatic measurements, with lower variability using the latter method. Conclusion Beat-to-beat automatic measurement of RWPT is feasible and provides excellent correlation with manual measurements, with less variability in the values. This algorithm may streamline the measurements during implantation. However, prospective evaluation is required to confirm operation of the algorithm in the clinical setting to include challenges such as electrical noise.

Description of the Knowledge and Attitudes of Pregnant Women Related to Prevention of Covid-19 Transmission

Coronavirus disease (COVID-19) is an infectious disease caused by SARSCoV-2, which has a shape and behaviour similar to the severe acute respiratory syndrome (SARS) virus. This disease has become a worldwide pandemic and causes acute respiratory tract disorders. Nationally, Indonesia is in the 19th highest position with total confirmed cases of COVID-19 with 49,578,590 cases and a death toll of 13.8 thousand cases. This research aims to determine the knowledge and attitudes of pregnant women in preventing transmission of Covid-19 during pregnancy. The method used in this research is a quantitative method with a descriptive approach. The population in this study was 39 pregnant women who did not work or were housewives, with the majority having a high school education and an age range of 20 - 35 years who met the inclusion and exclusion criteria. The data collection technique uses a questionnaire. The data analysis used in this research uses parametric statistics, and the scale used is based on interval and ratio measurements. Based on the results and discussion, the level of knowledge and attitudes of pregnant women regarding preventing the transmission of COVID-19 in Salatiga City is good.

Effect of Different Levofloxacin Doses on QTc Interval Prolongation in Multidrug-Resistant Tuberculosis Patients Treated with the 9-Month All-Oral Regimen

Introduction: The World Health Organization (WHO) has recommended the 9-month all-oral regimen for multidrug-resistant tuberculosis (MDR-TB) treatment. This regimen is expected to increase the treatment success rate. Bedaquiline, levofloxacin, and clofazimine are QT-prolonging drugs included in the 9-month all-oral regimen. Bedaquiline and clofazimine are given at the same dose for all patients, while levofloxacine dose is given in 750 mg and 1,000 mg based on the body weight. This study analyzed the correlation between different levofloxacin doses and certain factors on QTc interval prolongation. Methods: This observational retrospective study used the medical records of MDR-TB patients who underwent the 9-month all-oral regimen. Electrocardiography (ECG) for QTc interval measurement was recorded at the baseline before and 2 weeks after treatment. The measured variables included patient demographic data, body mass index (BMI), electrolyte levels, and comorbidities. Results: Thirty MDR-TB patients were included in this study. Gender, diabetes mellitus (DM), and levofloxacin dose did not correlate with QTc interval prolongation at 2 weeks after drug administration (p-values of 0.558, 0.197, and 0.134, respectively). Age, potassium level, magnesium level, calcium level, and baseline QTc interval also did not correlate with QTc interval prolongation at 2 weeks after drug administration (p-values of 0.433, 0.479, 0.705, 0.746, and 0.333, respectively). Multivariate analysis showed that the risk factor associated with QTc interval prolongation at 2 weeks after drug administration was a BMI of 0.013. Conclusion: Different levofloxacin doses did not correlate with QTc interval prolongation in MDR-TB patients treated with the 9-month all-oral regimen. The incidence of QTc interval prolongation was significantly associated with the lower BMI level.

High -resolution Time Interval Measurement Research based on FPGA

In modern scientific research and engineering practice, high -precision measurement of time interval between two or more physical events is often required. After years of development, there are currently many ways to measure a variety of high -precision time interval. If you implement different technologies, it can be divided into two categories: simulation and numbers. The simulation method is mainly to convert T to voltage by charging capacitance and then convert it into a digital amount through the modulus. However, the traditional simulation methods include the shortcomings of temperature sensitivity and long conversion time. Therefore, digital methods are generally used to achieve measurement. Common digital measurement methods include direct counting method, tap latency method, and cursor method. However, common measurement methods cannot meet actual needs. Therefore, this article relies on the FPGA platform to achieve a time interval measurement method with resolution to Ana second -level.

Delay in the Diagnosis of Patients With Head and Neck Cancer: Impact of Different Patient- and Healthcare Provider-Related Factors.

Background In our setup, head and neck cancer (HNC) is the most common, and patients frequently present at an advanced stage, which results in dismal outcomes. Delays on the part of the patient (such as resistance to seeking treatment) or the provider (such as misdiagnosis or an extended wait period for consultation) may be the cause of a late presentation. The presentation stage may vary depending on several factors, including age, gender, smoking status, job status, and education. Objectives The study aims to identify factors that lead to advanced-stage presentations of HNCs and to determine the delays brought on by patient- or healthcare provider-related factors and how these factors affect HNC disease staging among biopsy-proven HNC patients. Materials and methods Participants in the study were those who initially presented with a biopsy-verified HNC at the cancer clinic of the department of otolaryngology-head and neck surgery atPakistan Institute of Medical Sciences (PIMS), Islamabad. Patients answered questions on their first symptom presentation, past healthcare professional visits, and intervals between visits on a Cancer Symptom Interval Measure (C-SIM) questionnaire. For every patient, clinical and demographic information was gathered. TNM staging was completed. The test of significance was applied where applicable. Results Age, gender, education level, and smoking status had no bearing on the presentation stage. Patients without jobs present at a statistically significant higher stage (p = 0.038). The most prevalent histological form of HNC was squamous cell carcinoma 79 (82.29%), with theoral cavity and larynx being the most common sites of the disease30 (31.25%) and 29 (30.21%) respectively. Patients took an average of 5.28 ± 9.12 months from the onset of symptoms to their first appointment with a healthcare provider. Prior to diagnosis, the majority of patients saw three or more healthcare providers (range: 1-8). The duration from the initial visit to a healthcare provider to the initiation of treatment was 3.06 ± 5.88 months. Based on the stage at presentation, there were no discernible variations in the times to presentation (p>0.05). Conclusion Significant delays and high stage of presentation are caused by unemployment. The majority of the delay was caused by the patient's tardiness in seeing a medical practitioner, yet the presentation stage was not greatly impacted by this delay.

High-frequency spatial sediment source fingerprinting using in situ absorbance data

Sediment fingerprinting is a commonly applied approach to quantify catchment suspended sediment (SS) source contributions. However, due to the high workloads and costs involved in SS sampling and laboratory analyses, traditional procedures often result in a limited number of samples and sampling campaigns, which can hamper the capacity to capture the intra- and inter-storm variations in SS source activation and deactivation. A better understanding of the temporal dynamics in source contributions is needed, however, to improve the understanding of dynamic sediment generation and delivery processes for selecting management practices. In recognition of the extant need to improve high-frequency source estimates and to permit long duration measurement campaigns, the work reported herein presents a sediment fingerprinting procedure using UV–Vis absorbance spectra measured in situ with submersible spectrophotometer probes to estimate spatial SS source contributions based on a confluence-based monitoring strategy. The high-frequency (5-minute intervals) measurements were used to fingerprint SS sources during seven selected periods with varying hydrological conditions. Source apportionment estimates (MixSIAR model) were validated using an independent sediment budget. The results showed a mean deviation of 9.4 ± 6.0 %, compared with the sediment budget, for the seven periods combined (n = 7,282 time steps). The most accurate results (mean absolute error of 5.3 ± 4.3 %) were obtained for the period covering the July 2021 flood event in central Europe (return period for the monitored catchment > 20 years). Overall, modelled variations in SS source contributions mostly followed the sediment budget dynamics. This novel work highlights the potential for using spectrophotometer absorbance data for high-frequency and long-term sediment fingerprinting purposes. We argue that the presented method can lead to new opportunities to improve our understanding of SS sources and their dynamics.

Analysis of Big Data Obtained from Continuous Measurement of 22 Malodor-producing Substances in Korean Cattle Farms

Objectives : This research collected continuous (20-minute interval) measurement data of 22 compounds from cattle farms during a year in order to understand malodor emission characteristics and trends and also big data analysis was performed to analyze the relationships between malodor concentration and environmental factors such as wind direction and speed, temperature, and humidity.Methods : The measured substances were 22 compounds defined as ‘designated malodor-producing substances’ by Korean Ministry of Environment. Detection and concentration measurement were performed by gas chromatography with two kinds of columns (VB-WAX, and VB-1), and detectors (FID and PID). Sampling was carried out with pumping every 2 or 5 minute and thermal desorption was followed by chromatograph injection. Data obtained from analysis were stored with environmental variables such as temperature, humidity, wind speed, and wind direction from 1 August 2022 to 31 July 2023. Total number of measurement data was 26,280.Results and Discussion : Correlation analysis showed that temperature was correlated with dimethyl disulfide, and iso-valeraldehyde, and humidity was correlated with toluene, iso-butylalcohol, and trimethylamine. Six principal components explained 60.7% of total variance and two principal components, PC 1 and PC 2, were selected and analyzed. PC 1 was strongly related with volatile organic compounds and PC 2 was related with acid compounds. Together with bipolar plot results, PC 1 was defined as volatile properties and PC 2 as acidic characteristics, respectively. Multiple regression with principal components as dependent variables and environmental variables as independent showed relatively small value of adjusted R2 except PC 1 of 0.539.Conclusion : Malodorous compounds tended to diffuse and move together with similar molecular characteristics which made the detected concentration similar in patterns. Though PC 1 had correlation with environmental variables through multiple regression analysis, it can be explained as chemical compound’s characteristics depends on temperature, humidity, and wind.

Examining the Light Heart Mobile Device App for Assessing Human Pulse Interval and Heart Rate Variability: Validation Study.

Pulse interval is a biomarker of psychological and physiological health. Pulse interval can now be assessed using mobile phone apps, which expands researchers' ability to assess pulse interval in the real world. Prior to implementation, measurement accuracy should be established. This investigation evaluated the validity of the Light Heart mobile app to measure pulse interval and pulse rate variability in healthy young adults. Validity was assessed by comparing the pulse interval and SD of normal pulse intervals obtained by Light Heart to the gold standard, electrocardiogram (ECG), in 14 young healthy individuals (mean age 24, SD 5 years; n=9, 64% female) in a seated posture. Mean pulse interval (Light Heart: 859, SD 113 ms; ECG: 857, SD 112 ms) demonstrated a strong positive linear correlation (r=0.99; P<.001) and strong agreement (intraclass correlation coefficient=1.00, 95% CI 0.99-1.00) between techniques. The Bland-Altman plot demonstrated good agreement for the mean pulse interval measured with Light Heart and ECG with evidence of fixed bias (-1.56, SD 1.86; 95% CI -5.2 to 2.1 ms), suggesting that Light Heart overestimates pulse interval by a small margin. When Bland-Altman plots were constructed for each participant's beat-by-beat pulse interval data, all participants demonstrated strong agreement between Light Heart and ECG with no evidence of fixed bias between measures. Heart rate variability, assessed by SD of normal pulse intervals, demonstrated strong agreement between techniques (Light Heart: mean 73, SD 23 ms; ECG: mean 73, SD 22 ms; r=0.99; P<.001; intraclass correlation coefficient=0.99, 95% CI 0.97-1.00). This study provides evidence to suggest that the Light Heart mobile app provides valid measures of pulse interval and heart rate variability in healthy young adults.

The Relationship between Body Mass Index and Frontal QRS-T Angle in Pregnant Women Undergoing Cesarean Section with Spinal Anesthesia.

Background and objectives: The frontal QRS-T angle is a novel parameter of myocardial repolarization. Weight gain during pregnancy and physiological changes during a cesarian section may affect the frontal QRS-T angle. We aimed to assess the effect of body mass index (BMI) on the frontal QRS-T angle in pregnant women undergoing cesarean section with spinal anesthesia. Method and materials: This study included 90 pregnant women. BMI was calculated for all pregnant women. The study population was divided into two groups: BMI < 30 (n = 66) and BMI ≥ 30 (n = 24). QT interval measurements and the frontal QRS-T angle were obtained from the report of an electrocardiography machine. Results: It was found that the pre-operative and post-operative frontal QRS-T angle (p = 0.045 and p = 0.007) and QTc interval (p = 0.037 and p < 0.001) were higher in pregnant women with a BMI ≥ 30 than in pregnant women with a BMI < 30. In addition, when compared to pre-operative values, the post-operative frontal QRS-T angle (from 24.0 [20.0-41.5] to 34.5 [19.5-50.0], p = 0.031) and QTc interval (from 420.6 ± 13.3 to 431.7 ± 18.3, p = 0.010) were increased in the BMI ≥ 30 group, whereas no significant post-operative increase was observed in the BMI < 30 group. In correlation analysis, BMI was positively correlated with the frontal QRS-T angle and QTc interval. Conclusions: The frontal QRS-T angle and QTc interval were importantly increased in pregnant women with a BMI ≥ 30 than in pregnant women with a BMI < 30. Also, after cesarean section operation with spinal anesthesia, the frontal QRS-T angle and QTc were increased significantly in the BMI ≥ 30 group, whereas no significant change was observed in the BMI < 30 group. Therefore, it is suggested to perform close post-operative monitoring in pregnant women with a BMI ≥ 30 undergoing cesarean section with spinal anesthesia.

Electrocardiogram (ECG) changes in working people with and without history of COVID-19

Introduction: During the COVID-19 pandemic, the greatest focus was on the respiratory system, but recently awareness has increased about the cardiovascular manifestations of the COVID-19 disease and the adverse effect of cardiovascular involvement on its prognosis. Since so far no comprehensive study has investigated electrocardiogram changes in patients with COVID-19 in Iran, the purpose of this study is to assess electrocardiogram changes in adults aged 20-70 with and without a history of COVID-19. Materials and Methods: The current study was a cohort study conducted on two groups of working people with a history of COVID-19 and controls without a history of COVID-19. The case and control subjects were selected randomly from the participants of the Yazd Health study and the Shahdieh cohort study. ECG was taken from both groups before and after Covid-19 and then QTc interval and ST segment measurements were recorded and interpreted. Results: In the present study, 77 patients including 45 patients with COVID-19 (58.4%) and 32 non-COVID-19 patients (41.6%) were selected. Heart rate/min before and after COVID-19 was 69.08±10.89 and 73.5±14.05, respectively (P&lt;0.01). There was a non-significant difference before and after COVID-19 in terms of QTi, and QTc (P&gt;0.05). Conclusion: According to the results of the present study, COVID-19 disease is associated with a change in heart rate in the two studies' participants, but no effect was observed on the parameters of QTi, and QTC. Therefore, it seems that echocardiography is not necessary in patients with COVID-19.

Harmonizing the CBCL and SDQ ADHD scores by using linear equating, kernel equating, item response theory and machine learning methods.

A problem that applied researchers and practitioners often face is the fact that different institutions within research consortia use different scales to evaluate the same construct which makes comparison of the results and pooling challenging. In order to meaningfully pool and compare the scores, the scales should be harmonized. The aim of this paper is to use different test equating methods to harmonize the ADHD scores from Child Behavior Checklist (CBCL) and Strengths and Difficulties Questionnaire (SDQ) and to see which method leads to the result. Sample consists of 1551 parent reports of children aged 10-11.5 years from Raine study on both CBCL and SDQ (common persons design). We used linear equating, kernel equating, Item Response Theory (IRT), and the following machine learning methods: regression (linear and ordinal), random forest (regression and classification) and Support Vector Machine (regression and classification). Efficacy of the methods is operationalized in terms of the root-mean-square error (RMSE) of differences between predicted and observed scores in cross-validation. Results showed that with single group design, it is the best to use the methods that use item level information and that treat the outcome as interval measurement level (regression approach).

Thorough QT/QTc study to evaluate the effect of a single supratherapeutic dose of islatravir on QTc interval prolongation in healthy adults.

Islatravir is a deoxynucleoside analog being developed for the treatment of HIV-1 infection. Clinical studies are being conducted to evaluate islatravir, administered in combination with other antiretroviral therapies, at doses of 0.25 mg once daily and 2 mg once weekly. In multiple previous clinical studies, islatravir was generally well tolerated, with no clear trend in cardiac adverse events. A trial was conducted to evaluate the effect of islatravir on cardiac repolarization. A randomized, double-blind, active- and placebo-controlled phase 1 trial was conducted, in which a single dose of islatravir 0.75 mg, islatravir 240 mg (supratherapeutic dose), moxifloxacin 400 mg (active control), or placebo was administered. Continuous 12-lead electrocardiogram monitoring was performed before dosing through 24 hours after dosing. QT interval measurements were collected, and safety and pharmacokinetics were evaluated. Sixty-three participants were enrolled, and 59 completed the study. Fridericia's QT correction for heart rate was inadequate; therefore, a population-specific correction was applied (QTcP). The placebo-corrected change from baseline in QTcP (ΔΔQTcP) interval at the observed geometric mean maximum plasma concentration associated with islatravir 0.75 mg and islatravir 240 mg was <10 ms at all time points. Assay sensitivity was confirmed because the use of moxifloxacin 400 mg led to a ΔΔQTcP >10 ms. The pharmacokinetic profile of islatravir was consistent with that of previous studies, and islatravir was generally well tolerated. Results from the current trial suggest that single doses of islatravir as high as 240 mg do not lead to QTc interval prolongation.

Vocalic and intervocalic intervals in the speech of educated Idoma speakers of English

The measurement of vocalic and intervocalic intervals, which has been proposed as a more reliable acoustic correlate of rhythm than inter-stress intervals or syllable duration, is usually not included in the description of the rhythm of Nigerian English, and little is known about how this contributes to the impression of rhythm in the speech of educated Idoma speakers of English. This study therefore investigated the speech rhythm of educated Idoma speakers of English by measuring vocalic and intervocalic intervals as acoustic correlates of speech rhythm. A carefully selected passage, read by 50 educated Idoma speakers of English, was analysed acoustically and statistically. The normalised pairwise variability index (nPVI) was employed to account for vocalic and intervocalic intervals in the speech of the participants in order show how this contributes to the impression of rhythm in their speech. The study indicated that there was no durational variability between successive vowels, in addition to low variability index values for vocalic and intervocalic intervals. These results showed syllable-timing rhythm. However, patterns from female participants along the continuum were less syllable timed than the male participants. There were also indications of sentence type variations with compound sentences, in some cases, less syllable timed than simple sentences.

A Multi-Sample Comparison and Rasch Analysis of the Evaluation of Children's Listening and Processing Skills Questionnaire.

Assessing listening difficulties and associated complaints can be challenging. Often, measures of peripheral auditory functions are within normal ranges, making clinicians feel unsure about proper management strategies. The range and nature of observed or experienced difficulties might be better captured using a qualitative measure. The Evaluation of Children's Listening and Processing Skills (ECLiPS) questionnaire was designed to broadly profile the auditory and cognitive problems often present in children with listening difficulties. This 38-item questionnaire was initially standardized in British children aged 6 to 11 years, was subsequently modified for use with North-American children, and was recently translated into Flemish-Dutch. This study aimed to compare typical scores of the Flemish version with the UK and US versions, and to evaluate and compare its psychometric quality based on Rasch analysis. We selected 112 Flemish children aged 6 to 11 years with verified normal hearing and typical development, and asked two caregivers of every child to fill out the ECLiPS. Data from two comparator samples were analyzed, including responses for 71 North-American children and 650 British children. Typical values for ECLiPS factors and aggregates were determined as a function of age and gender, and meaningful differences across samples were analyzed. Rasch analyses were performed to evaluate whether ECLiPS response categories work as intended, and whether item scores fit a linear equal interval measurement scale that works the same way for everyone. Item and person metrics were derived, including separation and reliability indices. We investigated whether items function similarly across linguistically and culturally different samples. ECLiPS scores were relatively invariant to age. Girls obtained higher scores compared with boys, mainly for items related to memory and attention, and pragmatic and social skills. Across ECLiPS versions, the most pronounced differences were found for items probing social skills. With respect to its psychometric quality, ECLiPS response categories work as intended, and ECLiPS items were found to fit the Rasch measurement scale. Cultural differences in responses were noted for some items, belonging to different factors. Item separation and reliability indices generally pointed toward sufficient variation in item difficulty. In general, person separation (and reliability) metrics, quantifying the instrument's ability to distinguish between poor and strong performers (in a reproducible manner), were low. This is expected from samples of typically developing children with homogeneous and high levels of listening ability. Across the languages assessed here, the ECLiPS caregiver questionnaire was verified to be a psychometrically valid qualitative measure to assess listening and processing skills, which can be used to support the assessment and management of elementary school children referred with LiD.