Dissertations / Theses on the topic 'Heart Diseases Treatment Victoria'

The population of adolescent and adults with congenital heart disease (CHD) has grown rapidly. Right ventricular (RV) dysfunction remains an important issue of concern in the long-term follow up of these patients. While circulating biomarkers have shown promise in the assessment and monitoring of adult patients with left heart diseases, little is known of the role of biomarkers in reflecting RV performance in CHD patients. Emerging circulating biomarkers that reflect underlying pathophysiologic processes have gained increasing attention. These include inflammatory cytokines namely tumour necrosis factor (TNF)-α, a biomarker of apoptosis annexin A5 (AnxA5), carboxy-terminal propeptide of type I procollagen (PICP) and amino-terminal propeptide of type III procollagen (PIIINP) that reflects collagen synthesis and turnover, low circulating levels of cardiac troponin T as detected by highly sensitive assay (hs-cTnT) that may reflect subclinical myocardial injury, and microRNAs found to be involved in cardiac remodeling. The studies in this thesis aimed to test the hypothesis that circulating biomarkers may be altered in patients with volume-overloaded right ventricles after repair of tetralogy (TOF) and pressure-overloaded right ventricles after atrial switch operation for complete transposition of the great arteries (TGA), and are related to indices of RV function. In patients after TOF repair, increased circulating PICP and PIIINP levels were associated with worse subpulmonary RV and left ventricular (LV) function. In particular, these propeptides correlated positively with LV mechanical dyssynchrony, implicating a possible role of increased collagen synthesis in its pathogenesis. Increased plasma levels of hs-cTnT were further found in 30% of female, but not male patients. Female patients with elevated hs-cTnT levels compared to those without had greater RV volumes and LV mechanical dyssynchrony. Independent correlates of hs-cTnT in patients as determined from multivariate analysis were sex and RV ejection fraction. MicroRNA profiling following validation confirmed alteration of circulating levels of miR-99b and miR-766 in repaired TOF patients, a pattern distinct from that reported for left heart diseases. The miRNA expression was, however, not related to the cardiac functional indices. Patients after atrial repair for TGA had significantly higher circulating AnxA5 and TNF-αlevels, but similar PICP, PIIINP levels, compared with controls. Elevated AnxA5 level was associated with impaired systemic RV myocardial deformation, increased subpulmonary ventricular eccentricity, and increased TNF-αlevel. Elevation of hs-cTnT is found in 39% of the patients. The positive correlation between hs-cTnT level and systemic RV volume may suggest a role of hs-cTnT in reflecting RV remodeling. Circulating microRNA expression profiling and further validation identified 11 upregulated microRNAs (miR-16, miR-106a, miR-144*, miR-18a, miR-25, miR-451, miR-486-3p, miR-486-5p, miR-505*, let-7e and miR-93). Among them, miR-18a and miR-486-5p correlated negatively with systemic ventricular myocardial acceleration during isovolumic contraction, a relatively-load independent measure of systemic RV contractility. To conclude, these biomarkers reflect in varying extent the structural, functional, biological alteration of the subpulmonary and systemic right ventricles of the CHD patients late after surgical repair. These data may provide new perspectives in the understanding of progressive RV dysfunction in the adult CHD population and hopefully shed more lights on novel therapeutic interventions.
published_or_final_version
Paediatrics and Adolescent Medicine
Doctoral
Doctor of Philosophy

Mitral Valve Prolapse Syndrome (MVPS) is a benign psychosomatic cardiac condition that can severely impair one's quality of life. Symptoms targeted in this study include, atypical chest pain, palpitations, anxiety, panic, and shortness of breath.This study was undertaken to examine the effects of a diaphragmatic breathing intervention on the symptoms and underlying mechanism of dysautonomia in a small group of symptomatic females with MVPS. The intervention was based on both yoga theory and cardiorespiratory empirical studies.Seven of eight participant's completed the nine week study using a single subject multiple baseline design across subjects. Participant's began a respiratory retraining intervention, in a weekly staggered pair start, after the first week of baseline measurement. Respiratory training consisted of a four week training in diaphragmatic breathing with home practice three times a day.Autonomic, behavioral, and cognitive systems were assessed. Dependent measures included State and Trait Anxiety, Anxiety Sensitivity, a Symptom Checklist, and Respiratory Sinus Arrhythmia (RSA). RSA is a current noninvasive measure of parasympathetic tone. Data on thoracic and abdominal respiratory predominance, respiration rate, diet, exercise, and adherence were also gathered.Data were analyzed via visual inspection of trends and phase average changes. Treatment effect sizes were calculated for standardized measures to indicate the meaningfulness of change.Two of the seven participants demonstrated a decrease in total symptom frequencies over the course of intervention. One participant demonstrated a weekly progression of lowered state anxiety scores from baseline through intervention. In terms of phase averages, three participants showed a lowering of state anxiety. All seven participants demonstrated lowered trait anxiety scores from pre to post intervention. Two of the seven participants demonstrated a meaningful pre to post intervention decrease in anxiety sensitivity. Respiratory training was effective in stabilizing abdominal respiration. Results regarding vagal tone could not be determined due to unreliable ECG data.In general, results were poor with several inconsistencies. Adherence rates were low and it did not appear that a therapeutic level of change in respiration rate was achieved. Controlling respiration rate may be a critical factor in the therapeutic effectiveness of respiratory retraining interventions.
Department of Counseling Psychology and Guidance Services

Ischemic heart disease (IHD) is the most common cause of death around the world. The underlying cause of IHD is myocardial ischemia as a result of progressive narrowing of coronary arteries due to atherosclerosis with potential thrombotic complications mediated by platelets. In addition to the role in hemostasis, platelets are increasingly recognized as an important mediator in this atherothrombotic disease. Basic management of IHD lies on medical therapy and coronary revascularization procedures. Percutaneous coronary intervention (PCI) is a commonly used revascularization procedure in the treatment of IHD especially for relief and reduction of symptoms. On the other hand, antiplatelet therapy is often administrated to patients undergoing PCI in an attempt to prevent major adverse cardiac events (MACE) following the procedures. However not all patients respond to the same degree of the antiplatelet therapy and some still develop MACE or stent thrombosis in the presence of the treatment with antiplatelet drugs. Recently a flow cytometric-based assay has been developed to monitor the effect of the antiplatelet drug, particularly the P2Y12 receptor antagonist, in patients treated with this kind of drug. This assay measures the activity of platelets as platelet reactivity index (PRI) based on the phosphorylation state of an intracellular platelet protein called vasodilator stimulated phosphoprotein (VASP). The measured value of PRI is inversely related to the response of patient to the antiplatelet drug. In this study, the response of patients to the P2Y12 receptor antagonist Clopidogrel was investigated following PCI. The PRI of patients was found to be significantly lower than normal subjects without taking this drug, indicating the therapeutic effect of this drug on the patients. However nearly one-third of patients (17 out of 59) studied were found to be non-responsive to clopidogrel treatment based on a cut-off established in this study for classifying patients into responders or non-responders. Furthermore, significant difference between the two types of stents used in PCI procedure, namely bare metal stent (BMS) and drug eluting stent (DES), was observed in the study. Patients receiving DES had nearly three times higher percentage of being non-responsive to clopidogrel than the BMS counterpart (45% vs. 16%, p<0.028). This study provides evidence that DES may be implicated in the non-responsiveness or drug resistance of clopidogrel in patient undergoing PCI.
published_or_final_version
Pathology
Master
Master of Medical Sciences

Despite major advances in pharmacological and surgical treatments of cardiovascular diseases (CVDs), clinical outcomes of patients with severe CVDs remain very poor. Most of medication and interventions currently available are only playing roles of preventing further damage to myocardium, declining the risk of on-going cardiovascular events, lifting the cardiac pumping efficiency and lower early mortality rates, none of these treatments can regenerate or repair damaged cardiac tissue or restore heart function. As a result, several new strategies have been explored to overcome limitations of current therapeutic approaches. One prospective is to replace dead cardiac vascular cells with young and green cells to repair or regenerate damaged heart myocardium. Several types of stem cells, including bone marrow hematopoietic stem cells, mesenchymal stem cells (MSCs), embryonic stem cell (ESCs)and induced pluripotent stem cells (iPSCs),have been tested as the candidates for treatment of CVDs. Among a myriad of types of stem cells, bone marrow derived MSCs(BM-MSCs) has received great attention based on several unique properties such as easy isolation and expansion, stable genetic background and low immunogenicity. However, the therapeutic efficacy of BM-MSCs derived from aging or diseased donors is impaired. The differentiation potential of BM-MSCs is gradually reduced with the increased culture time. Thus, it is urgent to identify some novel alternative sources for MSCs. Moreover, the potential mechanisms of MSCs therapy have not been understood totally. This thesis is designed to investigate the therapeutic efficacy and potential mechanisms of several novel types of MSCs, including hESC-MSCs and hiPSC-MSCs and Rap1-/--BM-MSCson several types of CVDs, including pulmonary arterial hypertension (PAH), dilated cardiomyopathy (DCM)and myocardial infarction (MI). In Chapter 4, it disclosed that hESC-MSCs have a better therapeutic efficacy than BM-MSCs in attenuation of PAH induced by monocrotaline in mice. The greater therapeutic potential of hESC-MSCs on PAH was not only attributed to the higher capacity of differentiation into de-novo vascular cells, but also attributed to higher cell survival rate and greater paracrine effects post-transplantation. In Chapter 5, it demonstrated that compared with BM-MSCs, iPSC-MSCs have a better therapeutic effect on doxorubicin-induced cardiomyopathy. Several potential mechanisms of action were involved in iPSC-MSCs-based therapy for cardiomyopathy. It demonstrated that iPSC-MSCs transplantation not only attenuated the generation of reactive oxygen species(ROS)and the level of inflammation, but also restored depletion of cardiac progenitor cells and promoted endogenous myocardial regeneration against doxorubicin induced cardiomyopathy. Moreover, mitochondrial transfer and paracrine actions of iPSC-MSCs played critical roles in the rescue for doxorubicin-induced cardiomyopathy. In Chapter 6, it uncovered that compared with wild type BM-MSCs,Rap1-/--BM-MSCs transplantation achieved a better benefit to MI induced by ligation of left anterior descending (LAD)coronary artery. Rap1-mediated NF-κB activity plays a key role in regulation MSCscytokine secretion profiles. The absence of Rap1 in MSCs leads to reduced pro-inflammatory cytokines secretion and enhanced MSCs survival capacity, thus yielding a better therapeutic efficacy. In conclusion, findings presented in this thesis provide important new insights regarding different novel types of MSCs, including those derived from ESC and iPSC. They have distinct mechanisms of action from BM-MSCs and provide superior therapeutic efficacy in various form of severe CVDs, including PAH and DCM. The safety and efficacy of these novel types of MSCs for treatment of CVDs deserve further investigations.
published_or_final_version
Medicine
Doctoral
Doctor of Philosophy

The purpose of this research was to obtain information on the content of education within cardiac rehabilitation programs, methods of administering education, what the barriers are to providing education and which professionals administer education.To reach this goal, a questionnaire was modified from a previous study and a pilot study was undertaken to establish reliability of the questionnaire. The questionnaire was then sent to a sample of 100 directors of cardiac rehabilitation programs belonging to The American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR). The questionnaire focused on 13 established areas of education within cardiac rehabilitation programs.Once the questionnaires were completed, the information was transferred to a table format based upon the 13 content areas. The following conclusions were drawn from the research and the data gathered: 11 of the 13 content areas are offered at least 84% of the time, the major barriers for the 13 content areas were lack of time and lack of interest on the patient's behalf, the most frequent methods of education for all 13 content areas were individual education, print materials, and group education, and the primary educator overall for all 13 content areas was the nurse followed by the exercise physiologist and dietitian/nutritionist.
Department of Physiology and Health Science

The aims of the present study were threefold: firstly, to further the understanding of the psychological response to heart disease; secondly, to consider the differences in the ways in which doctors and patients perceive heart disease; and thirdly, to consider how the doctor, patient, and condition interact within the illness process over a period of time. The nature of coronary heart disease (CHD) was considered, and the influence of psychological variables in CHD was discussed. Psychological factors in illness were examined, with particular emphasis on health beliefs, illness behaviour, compliance, and the doctor-patient relationship. Conclusions were drawn that to understand the illness process in heart disease, doctor, patient, and condition must be considered together, in an interactional framework. Two pilot studies were performed. The first study found that heart patients' health beliefs differed from a normal population. The second pilot study, with raised cholesterol patients, suggested the existence of five major components of the illness process: illness perception, illness effect, health orientation, doctor-patient relationship, and compliance. The main study considered groups of heart and cholesterol patients (experimental groups) and a group of general outpatients (control group), over a four-to-six month period. Patients were interviewed and given a questionnaire concerning their feelings regarding their condition. Doctors and judges also completed similar questionnaires. Results indicate that cholesterol patients rate superior coping to the other groups, and both experimental groups were higher than controls with regard to patient understanding, responsibility for health, and communication with doctor. Findings suggests alterations should be made in current conceptualization of illness behaviour. and that patient and doctor assessment of condition severity were found to be unrelated to illness behaviour. Doctor and patient perception of patient behaviour were found to be discrepant. Modifications in the treatment of heart and cholesterol patients are suggested.

Objective - to assess possibilities and specific characteristics of pediatric cardiology in treatment of congenital heart diseases (CHD), to evaluate efficacy of curative per-catheter procedures by means of analysis of immediate and long-term results. Retrospective study. The data of 422 patients who underwent 467 CHD palliative-curative procedures during the period since 1971 till 2007 were analyzed. It was postulated that balloon atrial septostomy resulted in statistically significant increase of atrial septal defect, increase of arterial blood oxygen saturation and decrease of interatrial preasure gradient (PG). Balloon pulmonary valvulotomy (BPV) is one of the most common curative procedures; this procedure has an effect of marked decrease of pressure gradient between the right ventricle and right atrium; development of pulmonary artery valve insufficiency is the most common complication of this procedure. The long - term results of BPV are less positive when higher PG prior the procedure is present and residual PG after the procedure is 36mmHg and higher. It was postulated, that closure of small (less than 3 mm) persistent ductus arteriosus using Cook coils may compete with surgical treatment successfully. It was stated, that the efficacy of balloon angioplasties of aorta, caval veins and pulmonary artery branches is transient; treatment using stents is more effective. It was postulated, that closure of congenital and postsurgical anomalies connections using coils is... [to full text]
Disertacijos objektas yra nustatyti intervencinės pediatrinės kardiologijos galimybes ir ypatumus, gydant įgimtas širdies ydas (ĮŠY), įvertinti gydomųjų perkateterinių procedūrų efektingumą, remiantis ankstyvųjų ir vėlyvųjų rezultatų analize. Tai retrospektyvus tyrimas. Analizuoti 422 ligonių duomenys, kuriems 1971 - 2007 m. buvo atliekamos 467 įgimtų širdies ydų paliatyvinės - gydomosios procedūros. Nustatyta, kad po balioninės tarpprieširdinės pertvaros septostomijos, statistiškai reikšmingai padidėja prieširdžių pertvaros defektas, didėja arterinio kraujo įsotinimas deguonimi ir mažėja spaudimų skirtumas (SS) tarp prieširdžių. Balioninė plaučių arterijos valvuloplastika (BPV) yra viena iš dažniausiai taikomų gydomųjų procedūrų, jos efektas – ryškus SS tarp dešiniojo skilvelio ir plaučių arterijos (PA) sumažėjimas, o pagrindinė komplikacija – PA vožtuvo nesandarumo vystymasis. BPV vėlyvieji rezultatai blogesni, kai yra didelis SS prieš procedūrą, o po procedūros liekamasis SS ≥ 36mmHg. Nustatyta, kad mažų iki 3mm AAL kimšimas Cook spiralėmis gali sėkmingai konkuruoti su operaciniu gydymu. Rasta, kad aortos, tuščiųjų venų ir plaučių arterijos šakų balioninės plastikos efektas trumpalaikis, o gydymas stentais daug sėkmingesnis. Nustatyta, kad anomalinių įgimtų ir pooperacinių kraujagyslinių jungčių užkimšimas spiralėmis yra saugus ir efektyvus gydymo metodas.

Purpose The purpose of this study was to explore the beliefs people with heart failure hold about their illness and its treatment and to determine any relationships between these beliefs and self-care using the Common Sense Model (CSM) of illness cognitions and behaviour as the theoretical framework (Leventhal et al, 1980). Methods Using a mixed methodology (Creswell and Plano Clark, 2007), findings from patient interviews were used to adapt the Revised Illness Perception Questionnaire (IPQ-R) (Moss-Morris et al, 2002) and the Beliefs about Medicines Questionnaire (BMQ) (Horne et al, 1999) in order to make them illness-specific. A questionnaire assessing self-care was developed based on the European Heart Failure Self-care Behaviour Scale (EHFScBS) (Jaarsma et al, 2003), the interview findings and a nominal group technique with specialist heart failure nurses. These questionnaires were used to determine beliefs and the relationship to behaviour in a cross-sectional survey of 169 patients with heart failure. Results A number of statistically significant correlations were found between beliefs and self-care. Most notably, perceived medication knowledge (r = 0.51, p ≤ 0.01), beliefs about the necessity of medication (r = 0.45, p ≤ 0.01) and illness coherence (r = 0.39, p ≤ 0.01). Multiple regression analysis revealed that 46% of the variance in self-care could be explained by illness representations and treatment beliefs (Adj. R2 = 0.46, F = 9.93, p = 0.00). Three factors were significant predictors of self-care - medication knowledge (β = 0.319, p = 0.003), a belief in the illness having serious consequences (β = 0.258, p = 0.008) and the impact of medication use on lifestyle (β = -0.231, p = 0.03). Discussion The exploration of illness representations revealed a realistic picture of heart failure with a cluster of beliefs around a chronic illness with serious consequences and a high number of symptoms. There was a strong belief in the necessity of medication but for some, medication use had a negative impact on daily life. Patients were confident in their knowledge of medication but this was reduced when family members took control of medication management. A number of beliefs were predictive of self-care, suggesting that interventions designed to maximise these beliefs and correct any misconceptions may enhance self-care and potentially improve clinical outcomes in this population.

Objective: Chronic obstructive pulmonary disease (COPD) is a common comorbidity in patients with heart failure, yet little is known about the impact of this condition in patients with acute decompensated heart failure (ADHF), especially from a more generalizable, community-based perspective. The primary objective of this study was to describe the in-hospital and post discharge mortality and treatment of patients hospitalized with ADHF according to COPD status. Methods: The study population consisted of patients hospitalized with ADHF at all 11 medical centers in central Massachusetts during 4 study years: 1995, 2000, 2002, and 2004. Results: Of the 9,748 patients hospitalized with ADHF during the years under study, 35.9% had a history of COPD. The average age of this population was 76.1 years, 43.9% were men, and 93.3% were white. At the time of hospital discharge, patients with COPD were less likely to have received evidence-based heart failure medications, including beta-blockers and ACE inhibitors/angiotensin receptor blockers, than patients without COPD. Multivariable adjusted in-hospital death rates were similar for patients with and without COPD. However, among patients who survived to hospital discharge, patients with COPD had a significantly higher risk of dying at 1 (adjusted RR 1.10; 95% CI 1.06, 1.14) and 5-years (adjusted RR 1.40; 95% CI 1.28, 1.42) after hospital discharge than patients who were not previously diagnosed with COPD. Conclusions: COPD is a common co-morbidity in patients hospitalized with ADHF and is associated with a worse long-term prognosis. Further research is required to understand the complex interactions of these diseases and to ensure that patients with ADHF and COPD receive optimal treatment modalities.

Objective: Chronic obstructive pulmonary disease (COPD) is a common comorbidity in patients with heart failure, yet little is known about the impact of this condition in patients with acute decompensated heart failure (ADHF), especially from a more generalizable, community-based perspective. The primary objective of this study was to describe the in-hospital and post discharge mortality and treatment of patients hospitalized with ADHF according to COPD status. Methods: The study population consisted of patients hospitalized with ADHF at all 11 medical centers in central Massachusetts during 4 study years: 1995, 2000, 2002, and 2004. Results: Of the 9,748 patients hospitalized with ADHF during the years under study, 35.9% had a history of COPD. The average age of this population was 76.1 years, 43.9% were men, and 93.3% were white. At the time of hospital discharge, patients with COPD were less likely to have received evidence-based heart failure medications, including beta-blockers and ACE inhibitors/angiotensin receptor blockers, than patients without COPD. Multivariable adjusted in-hospital death rates were similar for patients with and without COPD. However, among patients who survived to hospital discharge, patients with COPD had a significantly higher risk of dying at 1 (adjusted RR 1.10; 95% CI 1.06, 1.14) and 5-years (adjusted RR 1.40; 95% CI 1.28, 1.42) after hospital discharge than patients who were not previously diagnosed with COPD. Conclusions: COPD is a common co-morbidity in patients hospitalized with ADHF and is associated with a worse long-term prognosis. Further research is required to understand the complex interactions of these diseases and to ensure that patients with ADHF and COPD receive optimal treatment modalities.

Thesis (Ph.D.)--Biomedical Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Oshinski, John N.; Committee Member: Fyfe, Derek A.; Committee Member: León, Angel R.; Committee Member: Skrinjar, Oskar; Committee Member: Taylor, W. Robert.

Heart failure resulting from different forms of cardiomyopathy is defined as the inability of the heart to pump sufficient blood to meet the body's metabolic demands. It is a major disease burden worldwide and the statistics show that 50% of the people who have the heart failure will eventually die from sudden cardiac death (SCD) associated with an arrhythmia. The central cause of disability and SCD is because of ventricular arrhythmias. Genetic mutations and acquired modifications to RyR2, the calcium release channel from sarcoplasmic reticulum, can increase the pathologic SR Ca2+ leak during diastole, which leads to defects in SR calcium handling and causes ventricular arrhythmias. The mechanism of RyR2 dysfunction includes abnormal phosphorylation, disrupted interaction with regulatory proteins and ions, or altered RyR2 domain interactions. Many pharmacological strategies have shown promising prospects to modulate the RyR2 as a therapy for treating cardiac arrhythmias. Here, we are trying to establish a novel approach to designing new drugs to treat heart failure and cardiac arrhythmias. Previously, we demonstrated that all pharmacological inhibitors of RyR channels are electron donors while all activators of RyR channels are electron acceptors. This was the first demonstration that an exchange of electrons was a common molecular mechanism involved in modifying the function of the RyR. Moreover, we found that there is a strong correlation between the strength of the electron donor/acceptor, and its potency as a channel inhibitor/activator, which could serve as a basis and direction for developing new drugs targeting the RyR. In this study, two new potent RyR inhibitors, 4-methoxy-3-methyl phenol (4-MmC) and the 1,3 dioxole derivative of K201, were synthesized which are derivatives of the known RyR modulators, 4-chloro-3-methyl phenol (4-CmC) and K201. The ability of K201, 1,3 dioxole derivative of K201 and 4-MmC to inhibit the cardiac calcium channel is examined and compared at the single channel level. All of these compounds inhibited the channel activity at low micromolar concentrations or sub-micromolar concentrations.

This thesis explores the issue of men's access to chronic illness self management programs from a social constructionist perspective. A combination of research methodologies was used; a quantitative analysis to confirm gender differences in levels and patterns of service use; a qualitative analysis to gain an increased understanding of the factors affecting men's access; and a trial to test the application of the research findings. The clients and services of Arthritis Victoria were chosen as the setting for this research. The quantitative analyses were conducted on contingency tables and odds ratios and confirmed that men were under-represented as service users. The analyses also identified gender differences in patterns of service use. The qualitative analysis was based on a series of in-depth, semi-structured interviews. It was undertaken from a grounded theory approach to allow for the development of theoretical explanations grounded in the data. It was found that men's decisions to access chronic illness self management programs were strongly influenced by dominant social constructions of masculinity which constrained help-seeking and health management behaviour. However, the restrictive influence of hegemonic masculinity was progressively undermined by the increasing severity of the chronic condition until a crisis point was reached in terms of the severity of the condition or its impact on lifestyle. This resulted in a reformulation or rejection of hegemonic masculinity. The described conceptual framework was consistent for men from diverse social groupings, although it appeared less prominent in both younger and older men, suggesting that dominant social constructions of masculinity have the greatest influence on health decisions during the middle stage of adulthood when work and family obligations are greatest. The thesis findings informed the development of some guiding principles for reviewing the structure and delivery of chronic illness self management services for men. The guiding principles will have direct application in the planning of Arthritis Victoria programs, and implications for other chronic illness self management programs in Australia, and also in Western countries with a similar health and sociocultural setting to Australia.

Diseases of the heart and blood vessels - one of the leading causes of death and disability among the population all over the world. According to the World Health organization, cardiovascular disease is causes death of 16.7 million people per year. In Ukraine, during the last 15 years there has been increase in mortality in this pathology. In general the structure of mortality in Ukraine, cardiovascular diseases account for more than half. New technologies such as endovascular procedures and coronary artery shunting are becoming widely applied in Ukraine. The introduction of the new methods of myocardial revascularization expanded treatment options for patients with coronary artery diseases

Thesis (MSc)--University of Stellenbosch, 2007.
ENGLISH ABSTRACT: Introduction Cardiovascular disease is one of the leading causes of death in the world. Formation of harmful reactive oxygen species (ROS) is associated with several pathological conditions, and contributes to ischaemia/reperfusion injury. Antioxidants can be added to the diet in an attempt to decrease the prevalence of cardiovascular disease by decreasing the harmful effects of ischaemia/reperfusion injury. Red Palm Oil (RPO) consists of saturated, monounsaturated and polyunsaturated fatty acids and is rich in antioxidants such as -carotene, tocopherols and tocotrienols. It has previously been shown that RPO-supplementation improved reperfusion mechanical function. In these studies it was found that RPO might exert its beneficial effects during reperfusion through increased PKB/Akt pathway activity, which may lead to inhibition of apoptosis and improved mechanical function. Aims The aims of this study were: 1) to determine whether RPO-supplementation protected against ischaemia/reperfusion injury in the isolated perfused rat heart, 2) to confirm RPO-supplementation’s effect on the PKB/Akt pathway activity and, 3) to elucidate the regulators in the PKB/Akt pathway that RPOsupplementation influenced. Methods Male Wistar rats were divided into 4 groups, 2 control groups and 2 experimental groups. The 2 control groups were fed a standard rat chow (SRC) for 4 weeks. The two experimental groups received SRC and RPOsupplementation for 4 weeks. Hearts were excised and transferred to a Langendorff perfusion apparatus and perfused with Krebs-Henseleit buffer. Mechanical functional recovery was measured after 25 min of total global noflow ischaemia. The following parameters were also measured during various time points in the protocol: left ventricular develop pressure, heart rate, coronary flow, rate pressure product. Hearts were also freeze-clamped for biochemical analysis at 10 min during reperfusion. The biochemical analysis was aimed at determining PKB/Akt involvement. In a second protocol, hearts were subjected to the same perfusion protocol, but wortmannin was also added to the perfusion fluid, in order to inhibit PI3- kinase. Results Hearts from the RPO-supplemented rats showed an improved RPP recovery (92.26 ± 5.89 % vs 63.86 ± 7.74 %) after 10 min of reperfusion. This finding corroborated the findings of previous studies. Hearts of the RPOsupplemented rats perfused with wortmannin, showed increased RPP recoveries at several time points. Biochemical results showed that wortmannin did indeed inhibit PI3-K phosphorylation in the RPO-supplemented group, as was expected. The RPO-supplemented group that was perfused with wortmannin had an increased PKB/Akt (Ser473) phosphoyrylation, when compared to the wortmannin control group. It was also found that the combination of RPO and wortmannin had prosurvival effects. Discussion This study showed that RPO-supplementation offered protection against ischaemia/reperfusion injury in the Langendorff-perfusion apparatus at 10 min into reperfusion. Thereafter the significance of the protection was lost. This protection has been confirmed in several previous studies and several mechanisms have been proposed for this protection. Since no conclusive evidence exists on the precise mechanism of protection, our investigation focused on the regulators of the pro-survival PKB/Akt pathway. An improved functional recovery was also seen in the RPO-supplemented group that was perfused with wortmannin. This was an unexpected finding, because Wortmannin is a known PI3-kinase inhibitor (as was confirmed by our biochemical data). PI3-kinase phosphorylation leads to PKB/Akt phosphorylation and therefore, activation of a pro-survival pathway. It would be expected that wortmannin would inhibit PKB/Akt and thus decrease the survival of the cells. The RPO-supplementation thus reversed wortmannin’s detrimental effect to such an extent that the functional recovery was far better than RPO-supplementation alone. In the RPO + wortmannin group, PKB/Akt (Ser473) phosphorylation was increased, contrary to previous findings. This is an indication that RPO may have the ability to override wortmannin’s inhibitory effect on PI3-kinase, or that PKB/Akt (Ser473) may be phosphorylated independently of PI3-kinase.
AFRIKAANSE OPSOMMING: Inleiding Kardiovaskulêre siektes is een van die hoof oorsake van sterftes in die wêreld. Die vorming van skadelike reaktiewe suurstof spesies word geassosieer met verskeie patologiese kondisies en dra ook by tot isgemie/reperfusie skade. ‘n Moontlike manier om die voorkoms van isgemie/herperfusie skade asook kardiovaskulêre siektes te voorkom, is om antioksidante by die dieet te voeg. Rooi Palm Olie (RPO) bevat versadigde, mono-onversadigde en polionversadigde vetsure. RPO bevat ook ‘n oorvloed van antioksidante soos β- karoteen en tokoferole en tokotriënole. Dit is bewys in vorige studies dat RPO-aanvulling verbeter funksionele herstel. Hierdie voordelige effekte mag dalk wees agv verhoogde PKB/Akt pad aktiwiteit. Die PKB/Akt pad word geassosieer met die inhibisie van apoptose en verhoogde meganiese funksie. Doelwitte Die doelwitte van hierdie studie was om te bepaal of 1) RPO-aanvulling beskermende effekte teen isgemie/herperfusie skade in die geisoleerde rotharte het, 2) Bevestig of RPO-aanvulling wel die PKB/Akt pad beïnvloed 3). om die effekte wat RPO-aanvulling het op die reguleerders van die PKB/Akt pad te onthul. Metodes Manlike Wistar rotte is in 4 groepe verdeel. 2 Groepe kontrole rotte is ‘n standaard rotkosmengsel gevoer vir 4 weke. Die 2 eksperimentele groepe het ook ‘n standaard rotkosmengsel gekry plus ‘n RPO-aanvulling vir 4 weke. Harte is uitgesny en op ‘n Langendorff perfusie sisteem gemonteer en met Krebs-Henseleit buffer geperfuseer. Meganiese funksie herstel is gemeet na 25 min totale globale geen-vloei isgemie. Linker ventrikulêre ontwikkelde druk, harttempo, koronêre vloei en tempo druk produk is gemeet by verskillende tydpunte. Sommige harte is na 10 min herperfusie vir biochemiese analiese gevriesklamp. Die biochemiese analisiese was beoog om die PKB/Akt pad betrokkenheid te bepaal. ‘n Tweede stel harte is aan dieselfde perfusie protokol blootgestel, maar wortmannin (PI3-kinase inhibitor) is ook bygevoeg by die perfusie vloeistof. Resultate Die groep wat met RPO aangevul is, het na 10 min herperfusie, ‘n verbeterde tempo druk produk herstel getoon (92.26 ± 5.89 % vs 63.86 ± 7.74. Hierdie bevinding is ook met ander studies bevestig. ‘n Interessante bevinding was dat die groep wat met RPO aangevul is en met wortmannin geperfuseer is, ‘n verbeterde meganiese funksionele herstel getoon het. Biochemiese resultate het getoon dat wortmannin wel PI3-K fosforilering geinhibeer het. Die harte van die rotte in die groep wat aangevul is met RPO en daarna met wortmannin geperfuseer is, het ‘n toename in PKB/Akt (Ser473) fosforilering getoon, relatief tot die wortmannin geperfuseerde harte van die rotte in die kontrole groep. Hierdie groep (RPO-aanvulling en wortmannin perfusie) het beskermende effekte getoon. Bespreking Hierdie studie het getoon dat RPO-aanvulling beskerming gebied het teen isgemie/herperfusie skade in die Langendorff geperfuseerde rothart na 10 min herperfusie. Daarna is die beduidenheid van die beskerming verloor. Hierdie bevindings ondersteun die resultate van vorige studies. Verskeie moontlike meganismes is voorgestel vir die beskerming, maar die presiese meganisme is nog nie duidelik nie. In hierdie studie is daar gekyk na die reguleerders van die PKB/Akt pad. Geen vorige studies het al gefokus op RPO-aanvulling en sy effek op die reguleerders van die PKB/Akt pad nie. ‘n Onverwagte bevinding is dat harte van die rotte in die RPO + wortmannin groep ‘n verbeterde funksionele herstel getoon het. Wortmannin is ‘n PI3- kinase inhibitor. PI3-K fosforilering lei tot PKB/Akt fosforilering, wat tot sel beskerming lei. Dus, aangesien wortmannin PI3-K inhibeer, sou dit verwag word dat wortmannin sel beskerming sal verminder. Die RPO het egter die wortmannin se nadelige effekte tot so ‘n mate oorskrei dat die funksionele herstel baie beter was as die RPO-aanvulling alleen. Die verhoogde PKB/Akt (Ser473) fosforilering, wat gesien is in die RPO + wortmannin groep kan toegeskryf word aan RPO se vermoë om wortmannin se nadelige effekte te oorskrei. ‘n Moontlike verduideliking vir hierdie bevinding mag wees dat rooi palm olie PKB/Akt (Ser473) op ‘n PI3-K onafhanklike manier fosforileer.

Submitted in fulfillment of the requirements for the Degree of Masters in Technology: Cardiology, Durban University of Technology, 2012.
Cardiomyopathies and their resultant heart failure (HF) remain a major cause of cardiovascular morbidity and mortality (Wood and Picard, 2004). Idiopathic dilated cardiomyopathy (IDCMO) is a primary myocardial disease of unknown cause, characterized by left ventricular (LV) or biventricular dilatation and impaired myocardial contractility. Dilated cardiomyopathy (DCMO), along with rheumatic heart disease and hypertension (HPT), is one of the leading causes of HF in Africa. In fact, in an epidemiology study of 884 patients in Soweto, IDCMO was the second major cause of HF. Thirty five percent of patients in the study, with HF, had IDCMO (Sliwa, Damasceno, Mayosi, 2005). Methodology: Patients referred to the cardiomyopathy (CMO) clinic at Chris Hani Baragwanath hospital, situated in the echocardiographic lab, were recruited, provided they satisfied the exclusion and inclusion criteria and were enrolled after obtaining voluntary informed consent. From May 2009 to September 2010, 70 patients with IDCMO were recruited for this trial. Patients with DCMO were identified by means of echocardiographic criteria which included a left ventricular ejection fraction (LVEF) of less than 45% and an end diastolic dimension (EDD) of greater than of 52 mm (2D in long parasternal axis). Results: In the present study the prevalence of left ventricular (LV) thrombus in patients with IDCMO was 18.6%. When using Univariate logistic regression, the only independent predictors of LV thrombus formation was LVEF and age. However, when multivariate logistic regression analysis was applied to the data, the only predictor with a significant association was age. The reason for this is not clear. It is postulated that perhaps younger patients have differences in the pathophysiology of their disease such as a greater smoldering inflammatory component which may therefore predispose them to thrombus formation. For example the presence of IL-6 may be important in the formation of LV clot in cases of LV dysfunction (Sosin, Bhatia, Davis, Lip, 2003). The association between LVEF and LV thrombus was borderline significant. Conclusion: The prevalence of LV thrombus formation in this cohort of patients with IDCMO was 18.6%. Echocardiographic parameters alone cannot predict which patients are more likely to develop thrombus formation.
National Research Foundation

Heart failure is a cause of significant burden to both individuals and society. Individuals live with a disease where there is a decline in physical functioning, the experience of a range of symptoms including breathlessness and pain, frequent hospitalisations and death. The frequent hospital admissions that are usually precipitated by shortness of breath places an economic burden on the current health system. This burden of heart failure is expected to increase in the coming years due to factors such as the ageing population and improved survival from acute cardiac events. This current and predicted continuing burden has been recognised by the health system and has resulted in significant improvement in the pharmacotherapy and nonpharmacotherapy treatment of heart failure. Despite this improvement and with the exception of those few who receive cardiac transplantation, there is no cure for heart failure. Whist the advances in therapy have promoted significant improvements in heart failure management, symptoms including breathlessness (dyspnoea) remain a major issue. The Management of Dyspnoea in Advanced Heart Failure project explored and assessed the current therapeutic management of dyspnoea in advanced heart failure and examined two potential therapeutic options namely nebulised frusemide and long-term oxygen therapy. Following a comprehensive review of the nebulised frusemide literature, The Haemodynamic Effects of Nebulised Frusemide in Heart Failure study showed that nebulised frusemide did have an impact on the haemodynamic parameters of participants. Whilst many consider oxygen therapy as a common sense approach for breathlessness, the lack of scientific evidence for its use in chronic breathlessness with people who have normal or mildly low oxygen levels has prevented funding to supply oxygen therapy to this group of patients. The O2 Breathe Study is a palliative care study that is testing long-term home oxygen therapy versus medical air in patients who do meet the current funding arrangements. The analysis of the screening data showed that the symptom burden as a result of dyspnoea is similar to that seen in cancer and respiratory patients, and heart failure patients had lower levels of physical functioning than the respiratory group. Whilst the design of the studies in this thesis will not allow conclusions to be made regarding their efficacy for dyspnoea management in heart failure, they have provided preliminary data and hypotheses to be tested in the future.
Doctor of Philosophy (PhD)

Yes
Developing new methods to treat heart diseases is always a focus for basic research and clinical applications. Existing drugs have strong side-effects and also require lifetime administration for patients. Recent attempts of using nanoparticles (NPs) in treating atherosclerosis in animals and some heart diseases such as heart failure and endocarditis have provided hopes for better drug delivery and reducing of drug side-effects. In this mini-review, we summarize the present applications of using gold nanoparticles (GNPs) as a new drug delivery system in diseased hearts and of the assessment of toxicity in using GNPs. We suggest that conjugating existing clinical drugs with GNPs is a favorable choice to provide “new and double-enhanced” potentiality to those existing drugs in treating heart diseases. Other applications of using NPs in the treatment of heart diseases including using drugs in nano-form and coating drugs with a surface of relevant NP are also discussed.

Heart disease is the leading cause of death globally. Early diagnosis is the key to successful treatment. By providing noninvasive, non-ionizing, and real-time imaging, echocardiography plays a critical role in identifying heart disease. Compared to other imaging modalities, ultrasound has unparalleled temporal resolution. High frame-rate imaging has enabled the development of new metrics to characterize myocardial mechanics. Strain imaging measures the heart's deformation throughout the cardiac cycle, providing a quantitative assessment of cardiac health. The intention of this dissertation is to bring Myocardial Elastography (ME) closer to clinical realization. ME is a high frame-rate strain imaging technique for transthoracic and intracardiac echocardiography. This work consists of four Aims. There is a fundamental trade-off between spatial and temporal resolution in strain imaging. In Aim 1, the optimal transmit sequence that generates the most accurate and precise strain estimate was determined. Two common approaches to coherent compounding (full and partial aperture) were compared in simulation and in transthoracic imaging of healthy human subjects (n=5). The optimized subaperture compounding sequence (25-element subperture, 90° angular aperture, 10 virtual sources, 300 Hz frame rate) was compared to the optimized steered compounding sequence (60° angular aperture, 15° tilt, 10 virtual sources, 300 Hz frame rate) and was found to measure strain in healthy human subjects with equivalent precision. The optimal compounding configuration was then evaluated against two other high-frame rate transmit strategies, ECG-gated focused imaging, and wide-beam imaging, in simulation and in healthy subjects (n=7). Achieving the highest level of strain precision, ECG-gated focused imaging was determined to be the preferred imaging approach in patients capable of sustaining a breath hold, with compounding preferred in those unable to do so. Rapid diagnosis is essential to successful treatment of myocardial infarction. In Aim 2, ME's ability to track infarct formation and recovery, and localize infarct using regional strain measurments, was investigated in a large animal survival model (n=11). Infarcts were generated via ligation of the left anterior descending, imaging regularly for up to 28 days. A radial strain-based metric, percentage of healthy myocardium by strain (PHM_ε), was developed as a marker for healthy myocardial tissue. PHM_ε was strongly linearly correlated with actual infarct size as determined by gross pathology (R2 = 0.80). ME was capable of diagnosing individual myocardial segments as non-infarcted or infarcted with high sensitivity (82%), specificity (92%), and precision (85%) (ROC AUC = 0.90), and tracked infarct recovery from collateral reperfusion through time. Noninvasive strain imaging at rest can improve pre-test probability accuracy, and reduce unnecessary stress testing. In Aim 3, ME's potential to provide early diagnosis of coronary artery disease was investigated in an ongoing study. Patients undergoing myocardial perfusion imaging were recruited (n=126). Perfusion scores were used as the reference standard. Morphological transformations were integrated into the processing pipeline to reduce variability in the strain measurements. PHM_ε was reintroduced and used to differentiate between patients with and without coronary artery disease. ME was capable of distinguishing between normal patients and those with significant ischemia or infarct (subjects with perfusion defects at rest) with statistical significance (p < 0.05), although a greater sample size is needed to confirm the results. One of the most common treatments for arrhythmia, catheter ablation, can fail if the lesion line intended to terminate the abnormal rhythm is non-contiguous. In Aim 4, the gap resolution and clinical feasibility of Intracardiac Myocardial Elastography (IME) strain imaging, an ablation monitoring technique, was investigated. Lesion size estimation and gap resolution was evaluated in an open chest canine model (n=3), wherein lesion lines consisting of three lesions and two gaps were generated in each canine left ventricle via epicardial ablation. All gaps were resolvable. Average lesion and gap areas were measured with high agreement (33 ± 14 mm2 and 30 ± 15 mm2, respectively) when compared against gross pathology (34 ± 19 mm2 and 26 ± 11 mm2, respectively). Gaps as small as 11 mm2 (3.6 mm on epicardial surface) were identifiable. Patients undergoing ablation to treat typical cavotricuspid isthmus atrial flutter (n=5) were imaged throughout the procedure. In all patients, strain decreased in the cavotricuspid isthmus after ablation (mean paired difference of -17 ± 11 %, p < 0.05). Together, these Aims intend to translate a promising imaging method from research to clinical reality.

Despite successful education campaigns through the media, and the evolution of numerous treatments, ischaemic heart disease remains one of the biggest causes of morbidity and mortality in the Western World. Development of anti-arrhythmic drugs was largely halted in the late'80s and early '90s prior to the discovery of the myocardial persistent sodium current and in particular, prior to the discovery that the myocardial persistent sodium current is considerably enhanced by hypoxia. We hypothesised that persistent sodium current blockade may reduce the extent of myocardial damage and the incidence of arrhythmias, and in particular lethal arrhythmias, arising from ischaemic heart disease. METHODS: Patch clamping and fluorescence studies were performed to determine whether Riluzole blocked persistent sodium currents and calcium influx during hypoxia and reperfusion. Isolated heart studies were performed to determine whether Riluzole provided cardioprotection during ischaemia-reperfusion. Whole animal studies were performed to determine whether Riluzole reduced the extent of myocardial damage and the incidence of arrhythmias from ischaemia and/or from ischaemia-reperfusion. Whole animal studies were also performed to determine whether Riluzole reduced the extent of skeletal muscle damage from ischaemia and/or reperfusion. RESULTS: Riluzole was found to: block persistent but not transient sodium currents, inhibit calcium influx and enhance cell shortening, enhance recovery from global ischaemia, not affect monophasic action potentials, reduce the extent of ischaemic myocardial damage, reduce the extent of reperfusion myocardial damage, halve the number of animals developing sustained arrhythmias, not alter the phases of arrhythmias, reduce the incidence of all types of ischaemic Phase 2 arrhythmias, reduce the incidence of all types ofreperfusion Phase 2 arrhythmias, be a more selective persistent sodium current blocker and better antiarrhythmic and anti-ischaemic than Lidocaine, not possess class 1 antiarrhythmic properties, be positively inotropic, be positively lusitropic, reduce the extent of ischaemic damage in skeletal muscle, reduce the extent of reperfusion damage in skeletal muscle, and most importantly, be safe for administration at doses similar to those used for treating Amyotrophic Lateral Sclerosis. CONCLUSIONS: Riluzole appears to be extremely potent for treating ischaemic heart disease and for providing cardioprotection in the current setting where there are no other satisfactory drugs. Riluzole also appears to have potential in treating skeletal muscle ischaemic and reperfusion.

Cardiovascular disease remains the leading cause of death worldwide. A lack of curative treatments and a shortage of transplant hearts necessitate new approaches to cardiac repair. Recent advances, including the advent of pluripotent stem cell-derived cardiomyocytes and the development of tissue engineering techniques, represent promising new directions to remuscularize the heart or induce endogenous regeneration. However, these approaches are currently limited by the immaturity of differentiated cardiomyocytes and the inability of cardiomyocytes to functionally integrate with the damaged myocardium. Mimicking the cardiomyocyte niche, the myriad signals surrounding the cardiomyocyte, may enhance the utility of these cells. In this dissertation, each of the three aspects of the cardiomyocyte niche: physical signals, the extracellular matrix, and soluble factors, are examined for their ability to guide cardiomyocyte growth and function. We first explore the effect of electrical stimulation, a physical signal pervasive in the heart, on pluripotent stem cell-derived cardiomyocyte development and function. Stimulated cardiomyocytes are more mature, show greater cell-cell connectivity, and are more resistant to tachycardic stress. Cardiomyocytes adapt their beating rate to the stimulation frequency, an effect mediated by the emergence of a rapidly depolarizing cell type and ion channel expression. We next engineer cardiovascular tissue architecture, critical components of the extracellular matrix, using a micromolding approach and determine geometric parameters necessary for the induction of cardiomyocyte alignment and tissue synchrony. We finally test pluripotent stem cell-derived cardiomyocyte exosomes, soluble nanovesicles specifically packaged and secreted by the cell, in vitro and in vivo, demonstrating functional improvement and reduction of arrhythmia in the heart. Therefore, the use of the cardiomyocyte niche supports the interrogation of cellular function to enable new cell-based approaches for the reduction of arrhythmia or induction of repair in the heart.

Until now, the role of cyclin dependent kinase 5 (CDK5) in cardiac pathophysiology has not been explored. While CDK5 has been well studied in the neuroscience/Alzheimer’s field as a cyclin-independent kinase, there is currently no investigation into the cardiac-specific role of CDK5. Recently, it was established that inhibition of CDK5 in stem cell derived cardiomyocytes from individuals with Timothy Syndrome (TS) rescued the delayed inactivation phenotype; TS is a fatal genetic long QT syndrome (LQTS) caused by delayed inactivation of the L-type voltage gated Ca2+channel CaV1.2. While it is evident that CDK5 plays an important role in regulating CaV1.2 function, its role in cardiac tissue remains to be elucidated. To determine whether CDK5 is essential for cardiac function, two separate mouse models were established—a cardiac-deficient Cdk5 mouse model (Cdk5 flox x αMHC-MerCreMer+) and a Cdk5 activation mouse model via overexpression of Cdk5’s known activator, p35 (Cdk5r1/p35 OE x αMHC-MerCreMer+). Immediately after spatiotemporal induction of deficiency/activation of Cdk5 in adult mice, echocardiography, histology and proteomic analysis were performed to examine effects on cardiac structure and function. Analysis of cardiac function and morphology in Cdk5 deficient mice revealed severe systolic dysfunction and a dilated cardiomyopathy-like phenotype. These results were further validated by a pathway analysis of quantified global proteome changes. Conversely, mice with an activation of Cdk5 displayed only minor changes in cardiac function with a modest reduction in fractional shortening and ejection fraction. Notably, these mice did not have any significant changes in cardiac chamber morphology, nor any significant changes to their global proteome. Interestingly, however, phosphoproteomic analysis revealed over 3,000 differentially phosphorylated proteins. Pathway and gene ontology analysis of proteome changes revealed significant hits related to cell adhesion. Evidence for the extensively studied role of CDK5 in the brain has demonstrated a critical role for CDK5 kinase activity in the regulation of cell adhesion. Alterations in cell adhesion are observed in a number of cardiac pathologies including heart failure and dilated cardiomyopathy; it is therefore plausible that CDK5 potentially regulates cardiac function via cell adhesion mechanisms. A comparison of the phospho-proteome acutely after Cdk5 depletion vs the phospho-proteome acutely after Cdk5 activation, allowed for the identification of a novel cardiac-specific Cdk5 substrate, beta taxilin (Txlnb). Validation of this potential phospho-substrate with an in situ proximity ligation assay demonstrated the co-localization of Cdk5-Txlnb in wildtype mouse cardiac tissue sections. When looking at co-localization in Cdk5 deficient tissue sections, no signals were observed. Lastly, our lab obtained donor cardiac tissue samples from individuals who passed away due to either heart failure or non-cardiac causes (serving as control cardiac tissue). Analysis of cardiac tissue samples revealed a significant increase in both CDK5 and p35 expression in heart failure samples. Dysregulation of phosphorylation has been implicated in cardiac dysfunction, with known contribution to contractile failure and a number of cardiac pathologies including cardiomyopathies. These findings further support a role for CDK5 in cardiac function. In conclusion, it appears that CDK5 is imperative for the maintenance of healthy cardiac function. Cardiac-specific homozygous and heterozygous Cdk5 deficiency revealed severe systolic dysfunction along with a dilated cardiomyopathy-like phenotype. While the effects of Cdk5 activation in the heart need to be further investigated, initial findings report significant downstream effects on the phosphorylation of a number of proteins, including Txlnb. Moreover, Txlnb was identified as a potential novel cardiac-specific substrate of Cdk5. The importance of identifying a role for CDK5 in the heart extends beyond this study. CDK inhibitors have been at the forefront of drug development for cancer therapeutics and immunotherapy. While modulation of CDK5 activity may be beneficial in one physiological system, it may prove deleterious in another. It is therefore imperative that the full range of molecular and physiological roles of each CDK be fully elucidated prior to therapeutic application. Furthermore, outcomes from this study have the potential to be translational for drug discovery and the development of new therapeutic avenues for heart disease.

Tese de mestrado integrado em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2017
De acordo com os dados de 2017 da Organização Mundial da Saúde, as doenças cardiovasculares são a principal causa de morte a nível mundial. Se estes tipos de doenças não forem diagnosticadas e tratadas atempadamente, podem levar a insuficiências cardíacas ou outras complicações irreversíveis. As duas doenças cardiovasculares congénitas estudadas neste trabalho são a coarctação aórtica (CoA), caracterizada por uma estenose, habitualmente, na zona do arco da artéria aorta, e a doença da válvula aórtica (AvD), uma malformação ao nível da válvula aórtica. Estas doenças são responsáveis por cerca de 50,000 intervenções por ano. Deste modo, a melhoria métodos de diagnóstico e de intervenção adequados e eficientes é uma prioridade e pode levar ao decréscimo no número das intervenções, bem como reduzir a morbilidade e a mortalidade. A área de imagiologia médica de diagnóstico tem tido uma evolução significativa ao longo dos anos e é de extrema importância nas tentativas de substituição de métodos de diagnóstico invasivos. As imagens médicas são adquiridas e posteriormente processadas e analisadas, com recurso a programas adequados. Atualmente, é possível obter os valores de gradientes de pressão relativa a partir de Ecocardiografia Doppler e Ressonância Magnética. Contudo, os gradientes de pressão medidos no cateterismo cardíaco, o método gold standard para o diagnóstico de CoA e AvD, são gradientes de pressão absoluta. Nesta dissertação desenvolveu-se um método de diagnóstico de CoA e AvD, a partir dos mapas de pressão relativa no estreitamento da aorta e na válvula aórtica, respectivamente. O método matemático desenvolvido tem por base as equações de Poisson, resolvida com a condição de fronteira de Neumann utilizando os métodos de elementos finitos, e a de Navier Stokes para a conservação do momento. O método desenvolvido também tem em conta a informação proveniente da função de Windkessel da artéria aorta, uma artéria distensível. Esta função dá-nos o comportamento da propagação do pulso de pressão com uma velocidade de pulso de propagação. Deste modo, é observado um desfasamento temporal entre as curvas de fluxo da pressão e da velocidade, entre as duas regiões de interesse escolhidas. Deste modo, o método, denominado de Time-shift Corrected Pressure Maps (TCPM, sigla em inglês), permite obter os mapas de pressão absoluta, isto é, mapas de pressão que têm em conta o intervalo de tempo entre os picos de pressão na aorta descendente e ascendente, no caso do primeiro estudo, e antes e depois da válvula aórtica, no caso do segundo estudo. Os pacientes de ambos os estudos tinham indicação clínica para cateterismo cardíaco e foram submetidos a ressonância magnética cardiovascular de contraste de fase em tempo real (4D PC MRI, em inglês), para recolher as imagens ao nível da aorta e da válvula aórtica e os respectivos campos de velocidade da corrente sanguínea. O primeiro estudo tem como objetivo a aplicação do método TCPM a 27 pacientes de CoA (n=16 masculinos, n=11 femininos, faixa etária de 4 a 52 anos, idade média de 20±15 anos). Após aquisição das imagens, estas foram processadas usando programas específicos. Em primeiro lugar foi necessário segmentar a aorta, seguiu-se a seleção das regiões de interesse e, finalmente, a obtenção dos campos de velocidade e dos mapas de pressão relativa entre as duas regiões de interesse selecionadas. Após aplicação do método TCPM, foram aplicados testes estatísticos (correlação, teste t e Bland-Altman) para comparar os valores obtidos a partir de TCPM com os valores obtidos no cateterismo cardíaco. Após processamento das imagens dos 27 pacientes, 6 pacientes foram retirados do estudo. N=3 pacientes foram retirados porque a percentagem de fluxo que passa pelo estreitamento é insuficiente para calcular o gradiente de pressão a partir de TCPM e N=3 pacientes foram retirados porque a aorta não estava inserida por completo no FOV. As medições obtidas a partir de TPCM e cateterismo cardíaco têm uma correlação linear significante (R²=0,90; p<0,001). A partir dos gráficos Bland-Altman é possível verificar uma boa concordância entre as medições de ambos os métodos, com bias de -2,69 mmHg e os limites de concordância de ±4,74 mmHg. O teste de equivalência mostrou uma relação significante entre os métodos (p=0,007). O segundo estudo tem como objetivo a aplicação do método TPCM e o método da Área de Gorlin a 4 pacientes de AvD (n=4 masculinos, faixa etária 17 a 36 anos, idade média 27±7 anos). O método da Área de Gorlin permite obter o gradiente de pressão absoluta a partir da área geométrica da válvula e do fluxo total que passa nessa área. Após a aquisição das imagens, foi feito o processamento das mesmas. Numa primeira fase, as imagens foram segmentadas na região da válvula aórtica. Depois, as imagens segmentadas foram analisadas em dois programas distintos. O primeiro foi utilizado de forma a obter os campos de velocidade e os mapas de pressão relativa entre dois pontos antes e depois da válvula aórtica. O segundo permitiu definir a região da válvula como região de interesse e exportar os valores de velocidade, área, pressão relativa e fluxo absoluto nessa região. Os resultados mostram uma correlação linear significativa entre os valores de cateterismo cardíaco e de TCPM (R²=0,99; p<0,001). Os gráficos de Bland-Altman mostram uma boa concordância entre os valores de TCPM (24,75±22,50 mmHg) e de cateterismo (20,88±19,51 mmHg), com um bias de -3,87 mmHg e limites de concordância de ±3,64 mmHg. Os resultados também sugeriram uma ligeira subestimação dos valores do cateterismo cardíaco a partir do método da Área de Gorlin (14,47±13,00 mmHg), com um bias de 6,41 mmHg e limites de concordância de ±7,15 mmHg. Este estudo foi feito com uma amostra diminuta de 4 pacientes, o que não é suficiente para retirar conclusões com significância. Contudo, foi uma primeira abordagem positiva, que mostra a potencialidade que este método pode vir a apresentar. O método TCPM proposto neste projeto permite a medição não invasiva de gradientes de pressão absoluta a partir de mapas de pressão relativa em pacientes de CoA e AvD. Vários aspectos têm que ser tidos em conta de forma a garantir a eficácia deste método. Por exemplo, as regiões de interesse escolhidas têm que se cuidadosamente selecionadas de forma a serem perpendicular à direção do fluxo naquele local. Só desta maneira é possível obter o fluxo, os campos de velocidade e as pressões relativas corretas. Também, se o raio da estenose for menor que 2 voxéis, a relação sinal-ruído aumenta substancialmente, e a resolução especial da aquisição é insuficiente. Contudo, a aplicação do método TPCM a casos de grande estreitamento não é necessária visto que estes casos já são tipicamente identificados em imagens anatómicas de ressonância magnética e que o paciente segue automaticamente para intervenção quando a área do estreitamente representa cerca de 50% do valor de área típico da aorta. O método não invasivo TCPM apresenta uma boa concordância com o cateterismo cardíaco em termos da medição dos gradientes de pressão em CoA e AvD. Os bias e os limites de concordância entre cateterismo e TCPM foram substancialmente mais pequenos que os bias e os limites de concordância entre cateterismo e ecocardiografia Doppler e entre o cateterismo e o método da Área de Gorlin. Com os resultados apresentados já é possível ver o potencial desta técnica no processo de diagnóstico e decisão de intervenção em casos de CoA e AvD. Contudo, estudos com populações maiores será extremamente benéfico para validar clinicamente este método.
This dissertation aims to validate MRI-based time-shift corrected pressure mapping (TCPM) against cardiac catheterization in CoA and AvD patients. Also, in AvD patients, catheterization will be compared against Gorlin Area method. This project is divided in two independent studies: the first one for CoA patients and the second one for AvD patients, all with clinical indication for cardiac catheterization. In both CoA and AvD, clinical guidelines recommend treatment in the presence of a relevant pressure gradient. While reliable non-invasive measurement approaches would be crucial, the accuracy of currently available methods has been limited. In both studies, 4D PC-MRI was performed to compute relative pressure maps via Pressure-Poisson equation. To consider the patient-specific peak pressure time-shift from the ascending to the descending aorta and before and after the aortic valve, relative pressure gradient maps were corrected by the inertial term. Comparison between TCPM and invasive peak-to-peak measurements was performed using correlation, Bland-Altman plots and mean-equivalence t-test. In the first study, with a cohort of 21 patients with CoA, TCPM and catheter measurements showed significant linear correlation (R²=0.90; p<0.001). Bland-Altman plots demonstrated good agreement between TCPM and catheter derived pressure gradients with mean differences of -2.69 mmHg and 95% limits of agreement between -6.38 and 1.00 mmHg between methods. The mean-equivalence test was significant (p=0.007). In the second study, with a cohort of 4 patients with AvD, the catheterization measurements were compared against TPCM measurements. The results showed significant linear correlation (R²=0.99; p<0.001). Bland Altman plots showed a good agreement between TCPM (24.75±22.50 mmHg) and catheter derived peak-to-peak pressure gradients (20.88±19.51 mmHg), and suggested slight underestimation of the pressure gradients by the Gorlin Area method (14.47±13.00 mmHg). Non-invasive TCPM showed equivalence to pressure gradients from invasive heart catheterization in patients with CoA and AvD. However, in the AvD study, they were obtained for a very small cohort of patients and do not have sufficient statistical significance to validate the method for AvD patients.

For cardiotonic actions, DF caused a transient increase in contractility and a transient decrease in contraction rate in an isolated rat heart perfusion system. The positive inotropic effect and the negative chronotropic effect were generated by the dose-dependent inhibitions of Na+/K +-ATPase and Ca2+-ATPase respectively in rat heart homogenate. In both assays, Danshen exhibited more potent inhibitions than DF, while Fenge showed negligible inhibitory actions.
In vivo study on Spontaneously Hypertensive Rats (SHR) showed that DF could not restore the established high blood pressure to the normal level. Earlier DF treatment attenuated, but could not prevent, hypertension development. In aorta, DF improved endothelium-dependent vasodilation by potentiating acetylcholine-induced relaxation and basal nitric oxide (NO) production, and inhibiting endothelial Ca2+ATPases. Relaxation of vascular smooth muscle cells (VSMC) towards NO donors was also enhanced. For anti-oxidation, upon DF treatment, mRNA levels of superoxide dismutase (SOD), extracellular superoxide dismutase (ecSOD), catalase and glutathione peroxidase (GPx) were elevated in heart and aorta. However, studies on SOD and catalase demonstrated insignificant changes in the protein expression levels in both organs. For vasodilation, mRNA level of endothelial nitric oxide synthase (eNOS) in the aorta was upregulated, but no change on eNOS and phosphorylated eNOS (peNOS) proteins were detected. A parallel study showed that DF did not cause hypotension or improve antioxidant defense in normotensive Wistar Kyoto rats (WKY). These findings suggest the use of the Danshen and Fenge 7:3 (w/w) formulation on the comprehensive cardiovascular protection.
Previously established Danshen and Fenge 7:3 (w/w) formulation (DF) was shown to exhibit antioxidative activity by preventing oxidant-induced red blood cell hemolysis and H9c2 rat myoblast cell death in a dose-dependent manner, in which Danshen was demonstrated to be a more potent antioxidant than DF. Fenge showed no antioxidative property. The effect of in vivo ischemia-reperfusion was mimicked by the hypoxia-reoxygenation model of primary culture of neonatal rat heart cardiomyocytes. Danshen could protect cardiomyocytes against hypoxiareoxygenation damage.
Reactive oxygen species attack on cardiovascular system can lead to atherosclerosis and finally cardiac ischemia. Reperfusion, allowing the restoration of blood flow in treating atherosclerosis, in turn generates free radicals which irreversibly damage cardiomyocytes and endothelial cells. Endothelial cell damage eventually leads to hypertension. Radix Salviae Miltiorrhizae (Danshen) and Radix Puerariae Thomsonii (Fenge) have long been used together to treat various heart diseases in China. This project was focused on the antioxidative, cardiotonic and vasodilative effects of the aqueous extracts of Danshen and Fenge.
Lam Hung Ming.
"September 2006."
Adviser: Miu Yee Mary Waye.
Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1381.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (p. 218-230).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.

Indiana University-Purdue University Indianapolis (IUPUI)
Autonomic innervation of the heart begins in utero and continues during the neonatal phase of life. A balance between the sympathetic and parasympathetic arms of the autonomic nervous system is required to regulate heart rate as well as the force of each contraction. Our lab studies the development of sympathetic innervation of the early postnatal heart in a conditional knockout (cKO) of Src homology protein tyrosine phosphatase 2 (Shp2). Shp2 is a ubiquitously expressed non-receptor phosphatase involved in a variety of cellular functions including survival, proliferation, and differentiation. We targeted Shp2 in post-migratory neural crest (NC) lineages using our novel Periostin-Cre. This resulted in a fully penetrant mouse model of diminished cardiac sympathetic innervation and concomitant bradycardia that progressively worsen. Shp2 is thought to mediate its basic cellular functions through a plethora of signaling cascades including extracellular signal-regulated kinases (ERK) 1 and 2. We hypothesize that abrogation of downstream ERK1/2 signaling in NC lineages is primarily responsible for the failed sympathetic innervation phenotype observed in our mouse model. Shp2 cKOs are indistinguishable from control littermates at birth and exhibit no gross structural cardiac anomalies; however, in vivo electrocardiogram (ECG) characterization revealed sinus bradycardia that develops as the Shp2 cKO ages. Significantly, 100% of Shp2 cKOs die within 3 weeks after birth. Characterization of the expression pattern of the sympathetic nerve marker tyrosine hydroxylase (TH) revealed a loss of functional sympathetic ganglionic neurons and reduction of cardiac sympathetic axon density in Shp2 cKOs. Shp2 cKOs exhibit lineage-specific suppression of activated pERK1/2 signaling, but not of other downstream targets of Shp2 such as pAKT (phosphorylated-Protein kinase B). Interestingly, restoration of pERK signaling via lineage-specific expression of constitutively active MEK1 (Mitogen-activated protein kinase kinase1) rescued TH-positive cardiac innervation as well as heart rate. These data suggest that the diminished sympathetic cardiac innervation and the resulting ECG abnormalities are a result of decreased pERK signaling in post-migratory NC lineages.

Dissertation
The aim of this study was to determine the knowledge of persons with hypertension in a selected geographical area regarding cardiovascular risk factors in order to make recommendations for patient education. A quantitative, non-experimental, descriptive study was done in the form of a survey using a questionnaire as measuring instrument. The population was hypertensive patients from selected private medical practices in the western part of KwaZulu-Natal and the bordering eastern part of the Free State. Convenience sampling was used and 46 respondents participated in the study. Only 16 (35%) of the respondents achieved a percentage on or above the competency indicator of 50%. Respondents performed worst in questions where definitions, for example hypertension, were assessed. Recommendations for a patient education document, nursing practice and further research were made.
Health Studies
M.A. (Health Studies)