Towards a better understanding of the precordial leads : an engineering point of view

This thesis provides comprehensive literature review of the electrocardiography evolution to highlight the important theories behind the development of the electrocardiography device. More importantly, it discusses different electrode placement on the chest, and their clinical advantages. This work presents a technical detail of a new ECG device which was developed at MARCS institute and can record the Wilson Central Terminal (WCT) components in addition to the standard 12-lead ECG. This ECG device was used to record from 147 patients at Campbelltown hospital over three years. The first two years of recording contain 92 patients which was published in the Physionet platform under the name of Wilson Central Terminal ECG database (WCTECGdb). This novel dataset was used to demonstrate the WCT signal characterisation and investigate how WCT impacts the precordial leads. Furthermore, the clinical influence of the WCT on precordial leads in patients diagnosed with non-ST segment elevation myocardial infarction (NSTEMI) is discussed. The work presented in this research is intended to revisit some of the ECG theories and investigate the validity of them using the recorded data. Furthermore, the influence of the left leg potential on recording the precordial leads is presented, which lead to investigate whether the WCT and augmented vector foot (aVF) are proportional. Finally, a machine learning approach is proposed to minimise the Wilson Central Terminal

The effects of oral sodium bicarbonate supplementation on anthropometric measures in patients with chronic kidney disease:A systematic review and meta‐analysis of randomized clinical trials

Abstract Metabolic acidosis (MA) may play a key role in the pathogenesis of protein‐energy wasting (PEW) in patients with chronic kidney disease (CKD). To present a comprehensive synthesis of the effect of oral sodium bicarbonate (SB) supplementation on anthropometric measures in patients with CKD, a systematic review was undertaken in PubMed/MEDLINE, Web of Science, Cochrane CENTRAL, and Google Scholar, of relevant articles published prior to September 2022. The summary statistics of effect size, nonstandardized weighted mean difference (WMD), and 95% confidence interval (CI) were used to compare the effects of SB supplementation on anthropometric parameters vs. control group. To detect probable sources of heterogeneity, a series of predefined subgroup analyses were conducted. In total, 17 studies with 21 treatment arms, including 2203 participants (1149 cases, 1054 controls), met our inclusion criteria and were included in the meta‐analysis. SB supplementation had no significant effect on body weight (BW), midarm muscle circumference (MAMC), or lean body mass (LBM) in patients with CKD. There was a significant increase in body mass index (BMI) (MD: 0.59 kg/m2, 95% CI: 0.25 to 0.93, p = 0.001) after SB supplementation in the overall analysis. In subgroup analysis, LBM was increased in studies that were ≥ 24‐week duration (MD: 1.81 kg, 95% CI: 0.81 to 2.81) and in participants with BMI lower than 27 kg/m2 (MD: 1.81 mg/L, 95% CI: 0.81 to 2.81). SB supplementation may yield increases in BMI in predialysis CKD patients. However, our findings did not support the beneficial effects of SB supplementation on other anthropometric outcomes. There is an evident need for long‐term high‐quality interventions to confirm these findings

Animal protein intake is directly associated with serum level of pentraxin 3 in hemodialysis patients

Inflammation plays an important role in Cardiovascular disease (CVD) pathogenesis as the main cause of mortality in hemodialysis (HD) patients. Despite the relevance of nutrition and dietary intakes for inflammation status, the role of dietary protein sources remains unclear. The aim of this study was to evaluate the association between the different types of dietary protein and pentraxin 3 (PTX3) levels in HD patients. In this multi-center cross-sectional study, 227 adult patients undergoing HD for a minimum 90 days were recruited. A validated 168-item food frequency questionnaire was used to assess dietary intakes. Also, 5 ml blood samples were collected from each patient to measure the concentration of serum PTX3. Overall, 227 patients, including 63 women and 164 men, with a mean age of 58 years, participated in this study. There was a greater intake of animal protein per kilogram dry weight among patients with higher levels of PTX3 (0.46 vs. 0.54 g/kg; P = 0.035). In contrast, consumption of total protein and plant protein per kilogram dry weight was not different across PTX3 levels. Moreover, the chance of increased PTX3 concentration was directly associated with a one-unit increase in animal protein intake per kilogram dry weight, after adjusting for confounders. We did not observe any association between one-unit increases in plant protein intake per kilogram dry weight and chance of increased PTX3. In conclusion, animal protein intake was directly associated with circulating PTX3

Towards real-time heartbeat classification : evaluation of nonlinear morphological features and voting method

Abnormal heart rhythms are one of the significant health concerns worldwide. The current state-of-the-art to recognize and classify abnormal heartbeats is manually performed by visual inspection by an expert practitioner. This is not just a tedious task; it is also error prone and, because it is performed, post-recordings may add unnecessary delay to the care. The real key to the fight to cardiac diseases is real-time detection that triggers prompt action. The biggest hurdle to real-time detection is represented by the rare occurrences of abnormal heartbeats and even more are some rare typologies that are not fully represented in signal datasets; the latter is what makes it difficult for doctors and algorithms to recognize them. This work presents an automated heartbeat classification based on nonlinear morphological features and a voting scheme suitable for rare heartbeat morphologies. Although the algorithm is designed and tested on a computer, it is intended ultimately to run on a portable i.e., field-programmable gate array (FPGA) devices. Our algorithm tested on Massachusetts Institute of Technology-Beth Israel Hospital(MIT-BIH) database as per Association for the Advancement of Medical Instrumentation(AAMI) recommendations. The simulation results show the superiority of the proposed method, especially in predicting minority groups: the fusion and unknown classes with 90.4% and 100%

Does Omega-3 supplementation decrease carotid intima-media thickening in hemodialysis patients?

Objective: A randomized, double-blind, placebo-controlled clinical trial was performed to assess the effect of omega-3 supplementation (3 g/day) on atherosclerosis progression by measuring carotid intima-media thickness (cIMT) in hemodialysis (HD) patients. Methods: A total of 54 HD patients were randomized into two groups: Intervention group (n = 27), in which patients were given 3 g/day omega-3 for 6 months and placebo group (n = 27), in which patients received placebo using the same administration protocol. All patients underwent a carotid artery ultrasound scan to measure cIMT at baseline and at 6 months. Findings: cIMT decreased significantly in omega-3 group (0.79 ± 0.21 mm at baseline vs. 0.65 ± 0.18 mm at 6 months, P< 0.001). On the other hand, a nonsignificant increase in cIMT was seen in placebo group (0.75 ± 0.17 mm at baseline vs. 0.79 ± 0.17 mm at 6 months, P = 0.12). Moreover, cIMT was statistically significantly different between omega-3 and placebo groups at 6 months (P < 0.001). After 6 months, a statistically significant increase was observed in high-density lipoprotein level in omega-3 group compared to placebo group (P = 0.03). Urea reduction ratio was also statistically significantly higher in omega-3 than placebo group at 6 months (P = 0.03). No significant difference was observed in terms of other variables between the two groups. Conclusion: These data suggested that omega-3 supplementation plays a protective role in the progression of atherosclerosis in HD patients

Association of alcohol consumption with the prevalence and various stages of chronic kidney disease

Background: Considering that the effect of alcohol consumption trend on the prevalence of kidney damage and its progression has not been determined yet, the study aimed at investigating the association between alcohol consumption and the risk of chronic kidney disease (CKD) prevalence and progression at various stages of the disease. Materials and Methods: This cross-sectional study was performed on 3374 participants that referred to health-care centers in Isfahan from 2017 to 2019. Participants' basic and clinical characteristics (such as sex, age, education level, marital status, body mass index, blood pressure, alcohol consumption, comorbidities, and laboratory parameters) were evaluated and recorded. The alcohol consumption trend was classified as never, occasional ( 0.05) and the odds of stage 2 CKD prevalence as compared to stage 1 CKD prevalence (OR: 0.93 and 0.47; P > 0.05). However, adjusting the confounding factors revealed that occasional drinking as compared to nondrinking increased the odds of stage 3 and 4 CKD prevalence as compared to stage 1 CKD prevalence by 3.35 folds, respectively (P < 0.05). Conclusion: According to the results of this study, occasional drinking as compared to nondrinking significantly increased the odds of stage 3 and 4 CKD prevalence as compared to stage 1 CKD prevalence

Metabolic health status and renal disorders: a cross-sectional study

Abstract Previous surveys suggests that body mass index (BMI) may be positively related to development of chronic kidney disease (CKD). However, this association might be altered by metabolic syndrome. Therefore, we aimed to evaluate the association of metabolic health status with CKD. The present cross-sectional study was carried out on 3322 representative sample of Iranian adults. Metabolic syndrome was identified based on the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) and BMI was assessed by anthropometric measurements. Estimated glomerular filtration rate (eGFR) was calculated by modification of diet in renal disease-Chronic Kidney Disease Epidemiology Collaboration (MDRD-EPI) formula. Subjects were categorized into four phenotypes: metabolically healthy normal weight (MHNW), metabolically healthy overweight and obesity (MHO), metabolically unhealthy normal weight (MUHNW), and metabolically unhealthy overweight and obesity (MUHO). Based on multivariate-adjusted models, the risk of CKD was significantly higher in MUHO compared with MHNW (OR: 1.48; p < 0.05). Although MUHNW and MUHO were associated with lower eGFR and albuminuria, the significant association was not observed in case of hematuria. Furthermore, subjects with kidney stones tended to be in MHO (OR: 1.42; p < 0.05) and MUHO phenotypes (OR: 1.64; p < 0.05), in comparison to the MHNW phenotype. The odds of kidney disorders were higher in adults with metabolic syndrome, regardless of BMI. However, this relationship might be strengthened by the concomitance of metabolic syndrome and obesity. To verify our findings, clarify the causality, and elucidate the underlying mechanisms, further research are warranted

On the “Zero of Potential of the Electric Field Produced by the Heart Beat”. A Machine Capable of Estimating this Underlying Persistent Error in Electrocardiography

Modern electrocardiography (ECG) uses a constructed reference potential for the majority of leads. This reference potential, named after its inventor as the Wilson central terminal, is assumed to have negligible value and to be stationary during the cardiac cycle. However, the problem of its variability during the cardiac cycle has been known almost since the inception of 12-lead electrocardiography. Due to the cumbersomeness of the measurement system required to fully appreciate these variations, this topic has received scant research attention during the last 60 years. Taking advantage of modern electronic amplifiers’ capability to detect small voltages, drawing only femtoamperes from physiological equivalent signal sources and of the right-leg connection availability, we developed a complete electrocardiography device that, aside from the eight independent signals of the standard 12-lead ECG, allows direct recording of the Wilson central terminal components. In this paper, we present details of the circuit together with its initial clinical evaluation. For this trial, we recorded data from 44 volunteer patients at Campbelltown Hospital (Campbelltown, Australia) and we found that the Wilson central terminal amplitude, as foreseen by Frank and others in the 1950s, is not negligible, its amplitude in relation to the lead II is, on average, 51.2%, and thus it may be clinically relevan

A modern Wilson's Central Terminal electrocardiography database

Wilson's Central Terminal (WCT) is an artificially constructed virtual reference potential for surface electrocardiography (ECG). It is derived by averaging the voltage of the right arm (ΦR), left arm (ΦL), and left leg (ΦF), and is assumed to be steady and with negligible amplitude during the cardiac cycle. In order to measure WCT, in 1954, Bayley and Kinard encased volunteers inside a metal structure that was immersed in water for the duration of the recording. Due to the impracticality in measuring WCT using this method, it is an accepted methodological error in modern ECG. This study employed a novel ‘15-lead ECG device’ in which the ‘right leg’ is used as the ground reference terminal for measuring all signals. It was able to record WCT components (ΦR, ΦL, and ΦF) and a 12-lead ECG. Data from 85 patients (35 (41%) patients were female) at Campbelltown Hospital were recorded. Patients with pacemakers were excluded from the dataset. The average age of the study population was 65.31 years (SD 11.59). The absolute average amplitudes of WCT components among all patients were (ΦR = 0.076 mV, ΦL = 0.070 mV, and ΦF = 0.044 mV). Ten-second periods of recording without any artefacts was selected, and 413 10-second periods were extracted. It was found that recorded WCT is highly individual, and has standard ECG characteristics, including a P-wave, QRS complex, and T-wave

Einthoven unipolar leads : towards a better understanding of Wilson Central Terminal

Einthoven unipolar leads include the potential of the right arm, left arm, and left leg which, by definition, are used to form the Wilson central terminal (WCT) as the average of these three limbs leads. In a traditional 12-lead ECG system, it is not possible to measure WCT directly. It is assumed to both be steady during the cardiac cycle with the assumed value most commonly being -2/3 of the augmented vector foot (aVF) lead. Using our novel ECG device that records Einthoven unipolar leads in addition to traditional 12-lead ECG signals, we investigate whether the WCT and aVF are proportional and the WCT can accurately be replaced by -2/3 of the aVF lead. We use the Einthoven unipolar leads features to evaluate both of the assumptions in regards to the WCT amplitude and value