Variability of Time and Amplitude ECG Indicators in Older Adults

The purpose of this article was to determine the effect of the clinostatic test on the electrical properties of the myocardium in older adults leading an active lifestyle. Materials and methods. The study involved 38 people aged between 70 and 90 years living in a northern city (Syktyvkar, 61°N) and leading an active lifestyle. The indicators of the electrical properties of the cardiac muscle were determined before and after the clinostatic test. For this purpose, an ECG was recorded in the standard lead II in the standing and lying positions. Results. Using the method of paired comparisons, we showed a decrease in heart rate under the influence of the clinostatic test from 76 ± 10 beats/min to 64 ± 10 beats/min. The variability of ECG components according to pNN50 (the percentage of successive NN intervals differing from each other by more than 50 ms) in older adults in the standing position was, on average, two times lower than in the lying position. The PP interval increased from 0.81 ± 0.12 s (in the standing position) to 0.90 ± 0.10 s (in the lying position). The PT interval remained practically unchanged, staying at the level of (0.46 ± 0.07) – (0.49 ± 0.07) s. The TP segment grew from 0.35 to 0.42 ± 0.10 s. The RD amplitude was 1.04 ± 0.43 mV in the standing and 0.88 ± 0.30 mV in the lying position; the propagation rate of depolarization in the cardiac muscle was 245 ± 137 and 205 ± 106 mm/s, respectively. In addition, the paper discussed the mechanism of opposite reactions to the clinostatic test, i.e. increasing duration of cardiointervals and decreasing amplitude indicators. For citation: Irzhak L.I., Russkikh N.G., Parshukova A.N. Variability of Time and Amplitude ECG Indicators in Older Adults. Journal of Medical and Biological Research, 2021, vol. 9, no. 4, pp. 355–365. DOI: 10.37482/2687-1491-Z073

Prevention of pacemaker lead induced tricuspid regurgitAtion by transesophageal eCho guidEd implantation (PLACE Pilot)

Background Lead-induced tricuspid regurgitation (TR) is a frequent complication after pacemaker- and ICD-implantation that is associated with increased mortality and hospitalizations. Purpose The aim of this pilot study was to investigate if lead implantation guided by transesophageal echocardiography (TEE) is feasible and might be able to reduce lead-associated TR. Methods 21 patients with indication for new pacemaker/ICD including a trans-tricuspid lead implantation and TR < grade 2+ were prospectively enrolled and underwent TEE-guided lead implantation in addition to fluoroscopy. Leads were placed according to a dedicated echo protocol with focus on a transgastric en face view of the tricuspid valve targeting a lead position in a tricuspid valve commissure (preferentially postero-septal) and an apical ventricular lead position. (Figure 1) Transthoracic echocardiography (TTE) was performed before implantation and at discharge. 121 consecutive patients with standard lead implantation guided by fluoroscopy only served as a historical control group. TR was assessed by an experienced cardiologist and graded according to current guidelines. Results Key baseline characteristics of overall 124 patients with a mean age of 74 years didn't differ between groups. Of note, there was no significant difference regarding device type and baseline TR. TEE-guided lead implantation was possible in all 21 patients in the TEE-group in deep conscious sedation without occurrence of serious adverse events. Lead placement in a commissure, mostly postero-septal, was possible in 95.2% of patients without worsening of TR (20/21 pts). Based on TEE-guidance, lead position or length was altered in 52.4% of patients (11/21 pts, 6 pts with lead repositioning, 5 pts with modification of lead length). Compared to baseline, the 21 patients in the TEE-group did not show worsening of TR at discharge. In contrast, TR worsening by one grade occurred in 13.6% of patients (14/103 pts) with new onset of TR ≥2+ in 6.8% of patients (07/103 pts) in the control group (p=0.001). At discharge, lead position was evaluated using 2D and 3D TTE in a subset of patients. In all examined patients (14/14 pts) lead position was unchanged compared to intraprocedural position and stable during inspiration vs. expiration as well as in upright vs. horizontal position. Conclusion TEE-guidance during PM/ICD-implantation was safe and feasible and resulted in steps to optimize lead position in a relevant number of patients. At discharge lead position remained stable and TEE-guided lead implantation was associated with less worsening of TR than standard lead implantation guided by fluoroscopy. FUNDunding Acknowledgement Type of funding sources: None. TEE view with targeted lead position

Adsorption and determination of Lead in water and human urine samples based on Zn2(BDC)2(DABCO) MOF as polycaprolactone nanocomposite by suspension micro solid phase extraction coupled to UV–VIS spectroscopy

Today, the safety of water resource is the most important challenges which was reported by health and environment organizations. Water pollution can be created by hazardous contaminants of environmental pollutions. Lead as a heavy metal has carcinogenic effects in humans. Metal organic framework (MOF) is a highly porous material with different application. The Zn2(BDC)2(DABCO) is a good candidate of MOF based on zinc metal (Zn-MOF) with potential adsorption/extraction. In this work, Zn2(BDC)2(DABCO) MOF as polycaprolactone (PCL) nanocomposite were applied for lead adsorption/extraction from 50 mL of aqueous solution by ultra-assisted dispersive suspension-micro-solid phase extraction procedure (USA-S- µ-SPE) at pH=8. The samples were characterized by the FTIR, the XRD analysis, the FE-SEM and the BET surface area. The effect of parameters was investigated on lead absorption before determined by UV–VIS spectroscopy. The linear range, the detection limit (LOD) and enrichment factor of adsorbent were obtained 0.05-1 mg L-1, 0.25 μg L-1 and 48.7, respectively (r = 0.9992, RSD%=3.65). The absorption capacity of Zn2(BDC)2(DABCO) MOF for 50 mg L-1 of standard lead solution were obtained 133.8 mg g-1 for 0.25 g of adsorbent. The results indicate that this nanocomposite can have a good potential to develop different adsorbents.

Echocardiography features in determining left atrial dilatation in patients with hypertension

Background. The correct echocardiographic (Echo) determination of left atrial (LA) dilatation is a criterion for diagnosing heart failure with the preserved ejection fraction.Objective. The aim is to detect probable reasons for underestimating the LA area by Echo in hypertension patients.Design and methods. In the prospective study, the LA area was measured echocardiographically in 89 ambulatory patients (P-wave duration in standard lead II was > 0.1 mm in 57 patients and ≤ 0.1 mm in 32 patients) from the apical four- and two-chamber views with and without focusing on the LA, and from the subcostal four-chamber view.Results. A strong positive correlation was detected between ECG P-wave duration and the Echo LA area (r = 0.74). The LA areas were revealed to be different in patients with P-wave duration over 0.1 mm from the apical fourchamber view with optimization of displaying the LA (22.33 ± 0.68 and 19.02 ± 0.56 cm2, respectively). The maximum LA area was detected from the subcostal fourchamber view (24.41 ± 0.78).Conclusion. Thus, using the correspondence between the LA area and Pwave duration in standard lead II, optimization of displaying the LA, and additionally measuring the LA dimensions from the subcostal view, sonologists can avoid underestimating LA dimensions.

Validity and Reliability of the Scale to Report Emotional Stress Signs–Multiple Sclerosis (STRESS-MS) in Assessing Abuse and Neglect of Adults with Multiple Sclerosis

Background: Approximately 30% of people with multiple sclerosis (MS) require caregiving, with unknown prevalence of abuse and neglect. To explore these issues, we created the Scale to Report Emotional Stress Signs–Multiple Sclerosis (STRESS-MS). The objective was to develop, validate, and field-test a self-report questionnaire for screening people with MS for mistreatment. Methods: We developed the STRESS-MS questionnaire and administered it to 102 adults with advanced MS-related disability and 97 primary informal caregivers, correlating responses with direct observation of mistreatment, conducting an item analysis, and evaluating validity using a Longitudinal, Expert, All Data (LEAD) panel. Results: Most STRESS-MS subscales correlated highly with criterion-standard LEAD panel evaluations of mistreatment, with strong concurrent and discriminant validity. Nearly 53% of participants with MS reported experiencing psychological abuse; 9.8%, financial exploitation; 6.9%, physical abuse; 4.9%, neglect; and 3.9%, sexual abuse. Protective factors for people with MS included social support and older age; risk factors included depression and aggressiveness. The greatest risk factor was an informal caregiver who spent 20 or more hours per week caring for the person with MS. Conclusions: The STRESS-MS questionnaire is reasonably reliable and valid for detecting caregiver mistreatment in adults with MS. Although most informal caregivers are not abusive, this study highlights an underrecognized need to detect and prevent abuse and neglect of people with MS.

Cuffless Blood Pressure Measurement Using a Smartphone-Case Based ECG Monitor with Photoplethysmography in Hypertensive Patients

The availability of simple, accurate, and affordable cuffless blood pressure (BP) devices has the potential to greatly increase the compliance with measurement recommendations and the utilization of BP measurements for BP telemonitoring. The aim of this study is to evaluate the correlation between findings from routine BP measurements using a conventional sphygmomanometer with the results from a portable ECG monitor combined with photoplethysmography (PPG) for pulse wave registration in patients with arterial hypertension. Methods: The study included 500 patients aged 32–88 years (mean 64 ± 7.9 years). Mean values from three routine BP measurements by a sphygmomanometer with cuff were selected for comparison; within one minute after the last measurement, an electrocardiogram (ECG) was recorded for 3 min in the standard lead I using a smartphone-case based single-channel ECG monitor (CardioQVARK®-limited responsibility company “L-CARD”, Moscow, Russia) simultaneously with a PPG pulse wave recording. Using a combination of the heart signal with the PPG, levels of systolic and diastolic BP were determined based on machine learning using a previously developed and validated algorithm and were compared with sphygmomanometer results. Results: According to the Bland–Altman analysis, SD for systolic BP was 3.63, and bias was 0.32 for systolic BP. SD was 2.95 and bias was 0.61 for diastolic BP. The correlation between the results from the sphygmomanometer and the cuffless method was 0.89 (p = 0.001) for systolic and 0.87 (p = 0.002) for diastolic BP. Conclusion: Blood pressure measurements on a smartphone-case without a cuff are encouraging. However, further research is needed to improve the accuracy and reliability of clinical use in the majority of patients.

Lead Contamination Differences in the Muscle of Wild Turkeys Harvested with Lead and Copper-Plated Lead Shot

Despite the known deleterious effects lead exposure can have on humans, lead remains the most common type of ammunition used to harvest big game and upland game birds. We sampled wild turkey Meleagris gallopavo breast muscle shot with standard lead and copper-plated lead pellets to quantify lead residue concentrations within the wound channel, and we sampled multiple adjacent locations to measure the extent lead contamination spreads through tissue of harvested turkeys. We found that samples taken from the wound channel contained more lead (mean = 3.76 μg/g dry weight) than both samples taken adjacent to the wound channel (mean = 0.20 μg/g dry weight) and samples taken from >5 cm away (mean = 0.15 μg/g dry weight). Additionally, we found that birds harvested with standard lead ammunition did not differ in lead concentrations from those shot with copper-plated lead, suggesting that copper plating does not aid in reducing lead exposure. Our findings suggest that wild turkeys harvested with either lead or copper-plated lead shot have the potential to expose consumers, especially children due to their lower tolerance, to low levels of lead that could exceed daily consumption limits set by the Food and Drug Administration and Centers for Disease Control. However, elevated lead levels were confined to the wound channel, and thus proper preparation of game to remove tissue surrounding wound channels may eliminate or substantially reduce lead exposure from harvested game birds.

A Paper-Based Ultrasensitive Optical Sensor for the Selective Detection of H2S Vapors

A selective and inexpensive chemical paper-based sensor for the detection of gaseous H2S is presented. The triggering of the sensing mechanism is based on an arene-derivative dye which undergoes specific reactions in the presence of H2S, allowing for colorimetric analysis. The dye is embedded into a porous cellulose matrix. We passively exposed the paper strips to H2S generated in situ, while the absorbance was monitored via an optic fiber connected to a spectrophotometer. The kinetics of the emerging absorbance at 534 nm constitute the sensor response and maintain a very stable calibration signal in both concentration and time dimensions for quantitative applications. The time and concentration dependence of the calibration function allows the extraction of unusual analytical information that expands the potential comparability with other sensors in the literature, as the limit of detection admissible within a given exposure time. The use of this specific reaction ensures a very high selectivity against saturated vapors of primary interferents and typical volatile compounds, including alkanethiols. The specific performance of the proposed sensor was explicitly compared with other colorimetric alternatives, including standard lead acetate strips. Additionally, the use of a smartphone camera to follow the color change in the sensing reaction was also tested. With this straightforward method, also affordable for miniature photodiode devices, a limit of detection below the ppm scale was reached in both colorimetric approaches.

Calibration and validation of the Dynamic Wake Meandering model Part I: Bayesian estimation of model parameters using SpinnerLidar-derived wake characteristics

In this first part of a two-part work, we study the calibration of the Dynamic Wake Meandering (DWM) model using high spatial and temporal resolution SpinnerLidar measurements of the wake field collected at the Scaled Wind Farm Technology (SWiFT) facility located in Lubbock, Texas, U.S.A. We derive two-dimensional wake flow characteristics including wake deficit, wake turbulence and wake meandering from the lidar observations under different atmospheric stability conditions, inflow wind speeds and downstream distances up to five rotor diameters. We then apply Bayesian inference to obtain a probabilistic calibration of the DWM model, where the resulting joint distribution of parameters allows both for model implementation and uncertainty assessment. We validate the resulting fully-resolved wake field predictions against the lidar measurements and discuss the most critical sources of uncertainty. The results indicate that the DWM model can accurately predict the mean wind velocity and turbulence fields in the far wake region beyond four rotor diameters, as long as properly-calibrated parameters are used and wake meandering time series are accurately replicated. We demonstrate that the current DWM-model parameters in the IEC standard lead to conservative wake deficit predictions. Finally, we provide practical recommendations for reliable calibration procedures.