Cardiovascular disease (CVD) is the leading cause of death for people of most ethnicities on a global scale, and countless research efforts on the pathology of CVD has been well-characterized over the years. However, advancement in modern technologies, such as nanotechnology, has generated environmental and occupational health concerns within the scientific community. Current investigation of nanotoxicity calls into question the negative effects nanomaterials may invoke from their environmental, commercial, and therapeutic usage. As a result, further research is needed to investigate and characterize the toxicological implications associated with nanomaterial-exposure and CVD. We investigated the toxicity of multi-walled carbon nanotubes (MWCNT) and titanium dioxide (TiO2), which are two prominently used nanomaterials that have been previously linked to upregulation of inflammatory and atherogenic factors. However, the mechanistic pathways involved in these nanomaterials mediating detrimental effects on the heart and/or coronary vasculature have not yet been fully determined. Thus, we utilized two different routes of exposure in rodent models to assess alterations in proinflammatory and proatherogenic signaling pathways, which are represented in contrast throughout the dissertation. In our MWCNT study, we used C57Bl/6 mice exposed to MWCNTs (1 mg/m3) or filtered air (FA-Controls), via inhalation, for 6 hr/d for 14d. Conversely, intravenous TiO2 was administered to F344 male fisher rats, following 24h and 28d post-exposure to a single injection of TiO2-NPs (1 mg/kg), compared to control animals. MWCNT-exposed endpoints investigated the alterations in cholesterol transport, such as lectin-like oxidized low-density lipoprotein receptor (LOX)-1 and ATP-binding cassette transporter (ABCA)-1, inflammatory markers [tumor necrosis factor (TNF)-α], interleukin (IL)-1β/IL-6, nuclear-factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signaling factors involved in activation of the pathway, as well as intracellular/vascular adhesion molecule(s) (VCAM-1, ICAM-1), and miRNAs (miR-221/-21/-1), associated with CVD, were analyzed in cardiac tissue and coronary vasculature. Cardiac fibrotic deposition, matrix-metalloproteinases (MMP)-2/9, and reactive oxygen species (ROS) were also assessed. TiO2-exposure endpoints also involved alterations on cholesterol transport proteins via LOX-1 and ABCA-1, factors of inflammation, namely intracellular macrophages and interleukin (IL)-1β, MMP-2/9 activity and protein expression, fibrotic deposition, and ROS generation were analyzed via quantitative detection or histologically in both cardiac tissue and coronary vasculature. Results from both studies found alterations in fibrotic deposition, upregulation in LOX-1 expression and MMP-2/9 activity, and ROS generation; with a concurrent decrease in ABCA-1 expression in cardiac tissue and coronary vasculature. Individually, MWCNT-exposed endpoints had shown induction of cardiac TNF-α, MMP-9, IκB Kinase (IKK)-α/β, and miR-221 mRNAs; as well as increased coronary expression of TNF-α and VCAM-1. TiO2 studies found increases in IL-1β and MMP-9 protein expression, as well as intracellular macrophage induction. Both studies also found, through pre-treatment of NADPH oxidase inhibitor, apocynin, resulted in attenuation of nanomaterial-exposure mediated ROS production; with nitric oxide synthase inhibitor, L-NNA, also showing attenuation, but only in our MWCNT-exposed inhalation study. The results from both studies have demonstrated, through different routes of administration, exposures, and rodent models; that exposure to nanomaterials can mediate signaling pathways involved in initiation and/or progression of CVD.

Thesis (Ph.D. (Health Sciences)) -- University of Limpopo, 2022 / Background: Cardio Vascular Diseases(CVD) are presently the main cause of high mortality rate around the world. In sub-Saharan Africa, CVDs contributes to about 13% of deaths, with 80% deaths being recorded from developing countries. Behavioural and metabolic risk factors contribute to high mortality rate related to development of CVD which self-management strategies and practices could effectively prevent. Objective: To explore and develop ―self-management strategies‖ to prevent the development of CVD among patients living with chronic conditions at Ga Molepo Area clinics in the Limpopo Province, South Africa. Methods: “A mixed method exploratory sequential design study was conducted in four primary health care settings in a rural setting.‖ A semi structured one-on-one interviews were conducted with 43 patients selected by non-probability homogenous purposive sampling for a qualitative strand. Qualitative findings that was obtained with thematic ―Tesch‘s open coding data analysis method guided the quantitative strand‖. A simple random sampling was used to sample 347 respondents for the quantitative strand.Descriptive statistics and chi-square were applied to analyze data from the quantitative strand. ``Results: The qualitative results revealed that there is different self management strategies used by patients living with hypertension and Diabetes Mellitus as risk factors of CVDs. The self-management strategies include engaging in physical activity, eating a healthy balanced diet, drinking a lot of water and adhering to treatment. The quantitative revealed majority of participants(74%) perform mild exercises with 26% performing moderate exercis.On the other hand 7% are having stress and depression and while 7% are smoking.`` Conclusions:The findings indicated that by adopting self-management strategies could be an effective way of preventing the development of CVD which complicates to hypertension and diabetic mellitus .Therefore are encouraged to adhere to strategies adhere to treat,healthy diet and perform mild exercises Recommendations Hence, the government needs to appoint CHW permanently to strengthen the guidelines on the prevention of CVD and also the risk factors that put the communities at risk of developing CVD. Communities need to adhere to preventative strategies ti order prevent CVD. / SPICES Project - (Scaling -up Packages of Interventions for CVD prevention in Europe and sub-Saharan)

The purpose of this study was to verify the efficiency of McDowell's leisure counseling model for potential use with cardiac rehabilitation and intervention programs in effecting leisure attitudes, work attitudes, work self-concept, leisure self-concept and leisure satisfaction. To test the effectiveness of McDowell's model, an experimental research design, utilizing a pretest-posttest control group design, was used. The independent variable was counseling and the dependent variables, stated as alternative research hypotheses, were a positive effect on leisure self-concept, work self-concept, leisure attitudes, work attitudes and leisure satisfaction. Over a three month period, 24 adult subjects from an Adult Fitness Intervention Program volunteered for leisure counseling and were randomly assigned to one of two groups after which treatment was also randomly assigned. A test for homogeneity of regression revealed the subjects to be representative of the population on all variables except Work Self-Concept. In the study, a client typically was married, middle-aged, white-collar male worker. To measure the dependent variables, five instruments designed to be used with McDowell's model were used. The data obtained from the leisure counseling sample was first subject to a test for homogeneity of regression after which hypotheses one, two, three and five, were subjected to an analysis of covariance. The findings of the analysis of data allowed for the rejection of the null hypotheses and the acceptance of the research hypotheses for hypotheses two and five. For hypotheses one and three, the researcher failed to reject the null hypothesis, and rejected the research hypothesis. An interpretation of these findings suggested that leisure counseling using McDowell's model can affect one's leisure self-concept and leisure satisfaction. From the study it was concluded that for the sample studied McDowell's leisure counseling model can be said to have positively increased the clients' leisure self-concept and leisure satisfaction on a short term basis. It was also concluded that leisure counseling as a component of cardiac rehabilitation/intervention programs using McDowell's model was said to be neither effective or ineffective for the sample studies. These results must account for the fact that the research methodology was not able to identify the possible reactive effect of the pretest. / Ed. D.

Fine particulate matter (PM2.5) exposure is associated with increased risk of adverse cardiovascular health outcomes. Prior research shows that PM2.5 is disproportionately concentrated in communities of low socioeconomic status and with higher proportions of underrepresented ethnic and racial groups. However, little is known about the levels and trends in PM2.5 in American Indian (AI) communities. Prior work has estimated the risk of CVD outcomes from exposure to total PM2.5 and PM2.5 constituents in white, Black, Asian, and Hispanic populations; however, AI populations have been historically excluded from many of these studies. While certain behavioral and environmental CVD risk factors have been extensively studied in AI populations, the CVD health impacts of air pollution have not been previously characterized. In Chapter 2, we aimed to compare PM2.5 concentrations in AI- vs. non-AI-populated counties over time (2000 – 2018) in the contiguous US. We used a multi-criteria approach to classify counties as AI- or non-AI-populated. We ran linear mixed-effects models to estimate the difference in county-wide annual PM2.5 concentrations from monitoring sites and well-validated prediction models (measured and modeled PM2.5, respectively) in AI- vs. non-AI-populated counties, adjusting for population density and median household income. We estimated whether differences in AI- vs. non-AI-populated counties varied over time using interaction terms with calendar year. On average, adjusted measured PM2.5 concentrations in AI-populated counties were 0.79 μg/m3 (95%CI: 0.33, 1.26) lower than in non-AI-populated counties. However, this association was not constant over time; while in 2000, adjusted concentrations in AI-populated counties were 1.83 μg/m3 (95%CI: 1.53, 2.13) lower, by 2018, they were 0.84 μg/m3 (95%CI: 0.53, 1.15) higher than in non-AI-populated counties. Over the study period, measured PM2.5 mean concentrations in AI-populated counties decreased by 2.49 vs. 5.18 μg/m3 in non-AI-populated counties. Results were similar for satellite-based, modeled PM2.5. This study highlights disparities in PM2.5 trends between AI- and non-AI-populated counties over time, underscoring the need to strengthen air pollution regulations in tribal territories and areas where AI populations live. In Chapter 3, we further interrogate what components of PM2.5 could be contributing to the trends in total PM2.5. We estimated that adjusted concentrations of all six PM2.5 components in AI-populated counties were significantly lower than in non-AI-populated counties. However, component-specific trends varied over time. Sulfate and ammonium levels were significantly lower in AI- vs. non-AI-populated counties in 2000 but higher after 2011. Nitrate levels were consistently lower in AI- counties, while black carbon, organic matter, and soil levels showed inconsistent differences in AI- vs. non-AI-populated counties. This study highlights how differences in time trends of certain components by AI-populated county type, namely sulfate and ammonium, are driving steeper declines in total PM2.5 in non-AI vs. AI-populated counties, providing potential directives for air pollution regulations of key emissions sources on tribal and AI-populated lands. In Chapter 4, we estimated the effects of long-term PM2.5 exposure on CVD incidence, CVD mortality, and all-cause mortality in the Strong Heart Study (SHS), a longitudinal cohort of American Indian adults enrolled from centers in Arizona, Oklahoma, and North Dakota and South Dakota. We followed 2,115 participants from 2000–2019. Adjusted hazard ratios (95%CI) per 1μg/m3 increase in PM2.5 with CVD incidence, CVD mortality, and all-cause mortality were 1.09 (0.91, 1.30), 1.11 (0.91, 1.36), and 1.10 (0.96, 1.25), respectively. Center-specific models identified positive associations between PM2.5 and incident CHD (2.24 (1.40, 3.56)) and CVD (1.55 (1.05, 2.31)) in Arizona, marginally positive association between PM2.5 and CVD mortality in Oklahoma (1.29 (0.99, 1.68)), and null associations in North Dakota and South Dakota. This study assesses PM2.5 exposure and cardiovascular health effects in American Indian communities—addressing a critical gap in the representation of evidence in air pollution regulation. Further research on underlying mechanisms driving the unique associations observed across regions is needed.

Cardiovascular disease is the leading cause of death in the United States and the world. Progress in the development of new therapeutic strategies is hindered by shortcomings in our understanding of human myocardial pathophysiology and limitations in the ability of preclinical models to accurately predict successful clinical translation. The development of engineered models of the myocardium comprised of human cells derived from induced pluripotent stem cells has emerged as a promising strategy to overcome these problems. This dissertation builds on this work by developing a new engineered cardiac tissue platform and then utilizing it to investigate three distinct myocardial pathologies: (1) genetic restrictive cardiomyopathy, (2) autoimmune mediated myocardial injury, and (3) myocardial ischemia and reperfusion injury. Results from these studies provide new insights into therapeutic strategies for the first two conditions and describe substantial progress towards the creation of an innovative model of the third.

Submitted in fulfillment of the requirements of the degree of Doctor of Technology: Health Sciences, Durban University of Technology, Durban, South Africa, 2015. / Background: In a vulnerable low-income group with a confirmed high risk of cardiovascular disease, like the elderly in the Sharpeville care centre, an acute intervention is needed in order to improve their health profile. Previous studies suggested homocysteine lowering by vitamin B12, B6 and folate supplementation. The effect of vitamin B12, B6 and folate supplementation on the inflammatory response, thrombotic risk, lipid profile, hypertension, risk of metabolic syndrome and homocysteine metabolism in an elderly, black South African population has never been reported. Objectives: The main aim of this interventional study was to assess the effect of vitamins B12, B6 and folate supplementation at 200% RDA for six months on cardiovascular risk markers of an elderly semi-urbanised black South African community. Design: This study was an experimental intervention non-equivalent control group study design in 104 purposively selected samples of all the elderly attending the day-care centre. Setting and participants: A homogeneous group of respondents was included in the study. All subjects were equivalent in age (>60 years), race (black), unemployed/pensioners (socio-demographic) and 60 years and older attending a day care centre in Sharpeville, situated in the Vaal region, Gauteng, SA. Measurements: The distinctiveness of this study lies in the broad panel of parameters evaluating the CVR in correlation with the increased nutritional intake of vitamin B6, B12 and folate. These included: weight, height, waist, serum cholesterol, high density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, blood pressure, fibrinogen, high-sensitivity C-reactive protein (HS–CRP), homocysteine, vitamin B12, folate, glucose, insulin, adiponectin and fibronectin. Results: A very high incidence (66.36%) of hyperhomocysteinaemia is present in the sample. The mean serum homocysteine level in hyperhomocysteinaemic individuals decreased statistically significantly from 25.00±8.00 umol/l to 18.80±12.00 umol/l after the intervention. The number of respondents with an increased homocysteine level decreased from 100% (baseline) to 67% (follow-up). The supplementation was beneficial (statistically significant changes) to the glucose levels, fibrinolytic status, vitamin B6 serum levels, fibronectin levels and haemopoeiesis (decreased macrocytosis) of all the individuals (regardless of their homocysteine status). Conclusion: It is concluded that supplementation of vitamins B6, B12 and folate at 200% RDA for six months is an effective homocysteine-lowering approach as a strategy to reduce hyperhomocysteinaemia in an elderly population and thereby reduce cardiovascular risk (CVR). The supplementation intervention mentioned is not an effective multifactorial strategy to decrease CVR although beneficial effects were found with other CVR markers independent of homocysteine status.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007. / This thesis is concerned with the testing of an “auscultation jacket” as a means of recording heart sounds and electrocardiography (ECG) data from patients. A classification system based on Neural Networks, that is able to discriminate between normal and abnormal heart sounds and murmurs, has also been developed . The classification system uses the recorded data as training and testing data. This classification system is proposed to serve as an aid to physicians in diagnosing patients with cardiac abnormalities. Seventeen normal participants and 14 participants that suffer from valve-related heart disease have been recorded with the jacket. The “auscultation jacket” shows great promise as a wearable health monitoring aid for application in rural areas and in the telemedicine industry. The Neural Network classification system is able to differentiate between normal and abnormal heart sounds with a sensitivity of 85.7% and a specificity of 94.1%.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The research presented in this thesis serves to provide a tool to autonomously screen for cardiovascular disease in the rural areas of Africa. Vital information thus obtained from patients can be communicated to advanced medical centres by Telemedicine. Cardiovascular disease is then detected in its initial stages, which is essential to its effective treatment. The system developed in this study uses recorded heart sounds and electrocardiogram signals to distinguish between normal and abnormal heart conditions. This system improves on standard diagnostic tools in that it does not require cumbersome and expensive imaging equipment or a highly trained operator. Heart sound- and electrocardiogram signals from 62 volunteers were recorded with the prototype Precordialcardiogram device as part of a clinical study to aid in the development of the autonomous auscultation software and to screen patients for cardiovascular disease. These volunteers consisted of 28 patients of Tygerberg Hospital with cardiovascular disease and, for control purposes, 34 persons with normal heart conditions. The autonomous auscultation system developed during this study, interprets data obtained with the Precordialcardiogram device to autonomously acquire a normal or abnormal diagnosis. The system employs wavelet soft thresholding to denoise the recorded signals, followed by the segmentation of heart sound by identifying peaks in the electrocardiogram. Novel frequency spectral information was extracted as features from the heart sounds, by means of ensemble empirical mode decomposition and auto regressive modelling. These features proved to be particularly significant and played a major role in the screening capability of the system. New time domain based features were identified, established on the specific characteristics of the various cardiovascular diseases encountered during the study. These features were extracted via the energy ratios between different parts of ventricular systole and diastole of each recorded cardiac cycle. The respective features were classified to characterise typical heart diseases as well as healthy hearts with an ensemble artificial neural network. Herein the decisions of all the members were combined to obtain a final diagnosis. The performance of the autonomous auscultation system used in concert with the Precordialcardiogram device prototype, as determined through the leave-one-out crossvalidation method, had a sensitivity rating of 82% and a specificity rating of 88%. These results demonstrate the potential benefit of the Precordialcardiogram device and the developed autonomous auscultation software in a Telemedicine environment. / AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die navorsing van 'n outonome toetsing en sifting stelsel vir kardiovaskulêre siektes in landelike dele van Afrika, vanwaar mediese inligting per telefoon versend kan word. Die apparaat maak vroeë opsporing van kardiovaskulêre siektes moontlik, wat essensieel is vir effektiewe behandeling daarvan en ook die koste-effek van hierdie siektes verminder. In die huidige ontwikkelde stelsel word normale sowel as abnormale hart-toestande getipeer met opnames van hartklanke sowel as elektrokardiogram-seine. Voordele wat hierdie stelsel bo standaard diagnostiese metodes het, sluit die hanteerbare formaat van die hele apparaat sowel as die nie-noodsaaklikheid van duur beeldskeppende apparaat, of hoogs opgeleide personeel. Hartklank- en elektrokardiogramseine van 62 vrywilligers is met die prototipe "Precordialcardiogram" apparaat opgeneem om by te dra tot die ontwikkeling van die rekenaar sagteware vir die outonome auscultatsie stelsel en om die pasiëntsiftingsvermoë daarvan te toets. Die vrywilligers het 28 pasiënte van Tygerberg hospitaal met abnormale harttoestande ingesluit, sowel as ‘n kontrolegroep van 34 persone met normale harttoestande. Die outonome auskultasie-stelsel wat tot stand gekom het deur hierdie ondersoek maak gebruik van “wavelet” sagte drempeling om geraas uit die opgeneemde seine te verwyder. Daarna word die hartklanke gesegmenteer deur die pieke van die elektrokardiogram te identifiseer. Deur middel van "ensemble empirical mode decomposition" en outoregressiewe modellering, is nuwe inligting aangaande die frekwensie spektra van hartklanke, aanwysend van spesifieke harttoestande, verkry. Die beduidendheid van hierdie eienskappe is bewys en het 'n belangrike rol in die siftingsvermoë van die stelsel gespeel. Hierbenewens is nuwe tyd-gebaseerde eienskappe van die onderskeie kardiovaskulêre siektes wat tydens die ondersoek bestudeer is, geïdentifiseer. Hierdie eienskappe is geëien deur die energie-verhoudings tussen verskillende dele van die ventrikulêre sistolie en diastolie van elke opgeneemde hartsiklus te ontleed. 'n "Ensemble artificial neural network" is gebruik om die geïdentifiseerde eienskappe van hartsiektes sowel as normale harttoestande, te klassifiseer. Hierin is besluite van al die lede van die netwerk gekombineer, ten einde ‘n finale diagnose te maak. Die klassifiseerder se geldigheid is kruis-bevestig deur middel van die laat-een-uit kruisbevestigings-metode. Deur middel van die kruis-bevestigingsmetode is die bedryfsvermoëns van die outonome auskultasie-stelsel, toegerus met die "Precordialcardiogram" apparaat, repektiewelik op 82% vir sensitiwiteit en 88% vir spesifisiteit vasgestel. Hierdie resultate demonstreer die benuttingspotensiaal van die apparaat in 'n Telemedisyne omgewing.

Thesis (MScMedSc (Biomedical Sciences. Medical Physiology))--University of Stellenbosch, 2006. / Introduction: Obesity, which is implicated in the development of the metabolic syndrome (MS) is reaching epidemic proportions worldwide. MS significantly increases the risk of developing cardiovascular disease, which includes coronary artery disease. The current absence of animal models of diet induced obesity and the MS makes the investigation of the cardiovascular consequences of MS virtually impossible. As a result the effects of the MS on cardiac function, morphology and susceptibility to ischaemia are not well understood. Aims: We set out to: 1) develop and characterize a rodent model of dietinduced obesity and the MS, 2) investigate the susceptibility of hearts from these animals to ischaemia/reperfusion induced injury and, 3) determine whether angiotensin II (Ang II) and endothelin-1 (ET-1) plays a role in cardiac remodelling and/or the severity of ischaemia and reperfusion injury in this model. Methods: Male Wistar rats were fed a standard rat chow diet or cafeteria diet (CD) for 16 weeks. After the feeding period rats were sacrificed and blood and myocardial tissue samples were collected to document biochemical changes in these animals. Hearts were perfused on the isolated working rat heart perfusion apparatus to assess myocardial mechanical function before and after ischaemia. In a separate series of experiments, hearts underwent coronary artery ligation to determine the incidence and duration of ventricular arrhythmias during ischaemia and reperfusion, using electrocardiography. To assess a possible link between myocardial remodelling and ischaemia/reperfusion injury and myocardial Ang II and ET-1 content, we also measured these peptides under basal conditions and during ischaemia. Two-dimensional targeted Mmode echocardiography was used to assess in vivo myocardial mechanical function in control and obese rats. Results: After 16 weeks on the CD, obese rats satisfied the World Health Organization (WHO) criteria for the MS by having visceral obesity, insulin resistance, dyslipidaemia and an elevated systolic blood pressure, compared to control rats. Circulating Ang II levels, but not ET-1 levels, were elevated in CD fed rats. Obese rats had cardiac hypertrophy and ex vivo basal myocardial mechanical function was depressed in the CD fed rat hearts compared to control rat hearts. CD fed rat hearts had poorer aortic output (AO) recoveries compared to hearts from control rats. These hearts also had a higher incidence and duration of reperfusion arrhythmias. No such functional differences were seen in the in vivo experiments. No differences in basal or ischaemic myocardial Ang II and ET-1 levels were seen in either group. Conclusion: We have developed and characterized a model of diet-induced obesity and the MS. Obesity is associated with cardiac hypertrophy and an increased myocardial susceptibility to ischaemia and reperfusion injury in our model. The hearts from obese rats were also more prone to reperfusion ventricular arrhythmias. As myocardial function was only poorer in the ex vivo obese animal experiments, our data suggests that the obesity associated changes in function observed in the ex vivo studies may be related to the absence of circulating substrates or factors, which are essential for their normal mechanical function.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: This thesis investigates the feasibility of the laser Doppler vibrometer (LDV) for use in the autonomous auscultation of the human heart. As a non-contact measurement device, the LDV could become a very versatile biomedical sensor. LDV, stethoscope, piezoelectric accelerometer (PA) and electrocardiogram (ECG) signals were simultaneously recorded from 20 volunteers at Tygerberg Hospital. Of the 20 volunteers, 17 were confirmed to have cardiovascular disease. 3 patients with normal heart sounds were recorded for control data. The recorded data was successfully denoised using soft threshold wavelet denoising and ensemble empirical mode decomposition. The LDV was compared to the PA in common biomedical applications and found to be equally accurate. The heart sound cycles for each participant were segmented using a combination of ECG data and a simplicity curve. Frequency domain features were extracted from each heart cycle and input into a k-nearest neighbours classifier. It was concluded that the LDV can form part of an autonomous, non-contact auscultation system. / AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die haalbaarheid daarvan om die laser Doppler vibrasiemeter (LDV) vir die outonome beluistering van die menslike hart te gebruik. As 'n kontaklose meettoestel kan die LDV werklik 'n veelsydige biomediese sensor word. Twintig vrywilligers by die Tygerberg Hospitaal se LDV-, stetoskoop-, piësoelektriese versnellingsmeter (PV)- en elektrokardiogram (EKG) seine is gelyktydig opgeneem. Uit die 20 vrywilligers was daar 17 bevestigde gevalle van kardiovaskulêre siektes. Die data van drie pasiënte met normale hartklanke is as kontroledata opgeneem. Geraas is suksesvol uit die opgeneemde data verwyder deur 'n kombinasie van sagtedrempelgolf en saamgestelde empiriese modus ontladingstegnieke. Die LDV was vergelyk met die PV vir algemene biomediese gebruike en daar was gevind dat dit vergelykbare akkuraatheid het. Die hartklanksiklusse van elke deelnemer is gesegmenteer deur EKG data en 'n eenvoudskromme te kombineer. Frekwensiegebiedskenmerke is uit elke hartsiklus onttrek en in 'n k-naastebuurpunt klassifiseerder ingevoer. Daar is tot die gevolgtrekking gekom dat die LDV deel van 'n outonome, kontaklose beluisteringstelsel kan uitmaak.