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Administration of bicalutamide to LNCaP tumours induces a rapid and sustained hypoxia in the prostate. This treatment-induced hypoxia (> 14 days) promotes an increased synthesis of the CXC-chemokine Interleukin-8(CXCL8) co-incident with increasing oxygen tension and the restoration of tumour vascularisation. Consequently, the hypothesis under investigation was that hypoxia-induced CXCL8 signalling underpins resistance to bicalutamide-treated tumours and facilitates the adoption of more aggressive cancer cells. Culturing of22Rvl and cells under hypoxic conditions (mimicking the microenvironment effects resulting from bicalutamide treatment) increased the transcriptional activity of the AR, HIF-Ia and NF-KB, inducing expression of downstream target genes, associated with survival, metabolic adaptation and angiogenesis. The magnitude and duration of these increases was greater in LNCaP cells. Administration of bicalutamide or siRNA-mediated down-regulation of the AR failed to reduce expression of pro-angiogenic, pro-survival and metabolism-associated genes. However, concurrent knockdown of both HIF-Ia and NF-KB activity using gene-targeted siRNAs resulted in an effective repression of these hypoxia-induced disease-progressing genes. Expression of CXCL8 and its receptors, CXCRl and CXCR2, was also up-regulated in particularly in hypoxic LNCaP cells. CXCL8 signalling was shown to underpin hypoxiainduced AR, HIF -1 and NF-KB transcription in hypoxic LNCaP cell s, up-regulating genes associated with survival and metabolic adaptation. We have previously shown that HIF-l and NF-KB activity underpin the transcription of the CXCRI and CXCR2 receptors, suggesting that either suppression of the TFs or targeting of the CXCR1I2 receptors may provide strategies to enhance anti-tumour responses in hypoxic prostate cancer cells. The proteasome inhibitor Bortezomib was shown to attenuate hypoxia-induced AR- and HIF-l- activation but failed to reduce NF -KB activity. Instead, a direct targeting of CXCL8 signalling increased the sensitivity of LNCaP cells to bilcalutamide, and repressed hypoxia-induced transcription and expression of disease-promoting genes. Targeting CXCL8 signalling may therefore be a relevant strategy to enhance tumour response to anti-androgen strategies .

Heart failure (HF) is a clinical syndrome in which neurohormonal activation and cardiac remodelling occur in response to an index pathological event. Functional measures and biological markers of blood vessel function have been shown to be altered in HF, and abnormalities of microvascular function have been demonstrated in a variety of vascular beds. Treatment of HF involves medications which target abnormalities in the neurohormonal systems that regulate cardiovascular function, however the role of HMG Co-A reductase inhibitors (statins) in HF is unclear. Some observational and mechanistic studies have suggested benefit, however, results of prospective intervention trails have been disappointing. This thesis reports the vascular and biological abnormalities detectable in HF patients with systolic dysfunction compared to controls, and the vasular and biological effect of treatment with simvastatin in HF patients with systolic dysfunction. Treatment with simvastatin resulted in a significant reduction in Co Q IO levels in HF patients but not in coQ10ILDL ratio. There was a non-significant trend toward reduction in NT-proBNP levels. Other biomarkers studied were unchanged by treatment At baseline, differences between HF patients and controls were apparent in brachial artery flow mediated dilatation and doppler waveforms obtained from the retrobulbar circulation. No such differences were apparent in brachial artery waveforms. Treatment with simvastatin did not result in any change in doppler waveforms obtained from the retrobulbar circulation or brachial artery. Abnormalities in vascular function in HF are widespread and can be detected by novel wavelet analysis of doppler waveforms obtained from the retrobulbar circulation. 4 weeks of treatment with simvastatin did not produce improvements in measures of vascular function suggesting a lack of additional benefit over and above baseline treatment in this population at least over a short treatment period. Further research is required to see if longer periods of treatment may be effective .

Introduction: Monocytes play important roles in inflammation, thrombosis, angiogenesis and tissue repair and may contribute to the pathophysiology of heart failure (HF). Functional diversity is likely to stem from the presence of three distinct monocyte subsets, defined by flow cytometry (FC) as CD14++CD16-CCR2+ (Mon1), CD14++CD16+CCR2+ (Mon2) and CD14+CD16++CCR2- (Mon3). The aims of this thesis were to study the following parameters in patients with ischaemic HF: 1) monocyte subset numbers, 2) monocyte subset expression of surface receptors for inflammation, angiogenesis, cell adhesion molecules (CAM) and tissue repair, 3) cross-talk between monocytes and platelets in the formation of monocyte-platelet aggregates (MPAs). Methods: Monocyte subsets were analysed by FC on venous blood samples at baseline in 51 patients admitted with acute HF (AHF), 42 with stable HF (SHF), 44 with stable coronary artery disease (CAD) without HF and 40 healthy controls (HC). Plasma levels of inflammatory cytokines were also measured by flow cytometric bead array technology. In AHF, additional longitudinal samples were taken at discharge and 3 months. Results: Compared to CAD controls, patients with SHF had higher counts of Mon2 and MPAs associated with Mon2, alongside increased expression of inflammatory markers and CAM receptors on Mon2. Compared to SHF, those with AHF had higher counts of Mon1, Mon2 and MPAs associated with Mon1 and Mon2. Patients with AHF also had increased expression of angiogenic receptors on Mon1 and increased expression of angiogenic receptors, scavenger receptors and CAM receptors on Mon2. After adjusting for confounders, counts of Mon2, MPAs associated with Mon2 and expression of VCAM-1R on Mon2 were associated with clinical outcomes in AHF. Conclusions: Differences in monocyte subset numbers and cell surface receptor expression are seen in patients with HF. Mon2 appears to have a prognostic role in patients with AHF, however larger studies are required to confirm these findings.

This study investigated the role of prouroguanylin (ProUGN) and proguanylin (ProGN), members of a novel class of peptides with natriuretic activity in heart failure (HF), a disorder of declining cardiac output associated with disturbed sodium and water homeostasis. The hypothesis was that ProUGN and ProGN activity is dysregulated in chronic and acute HF. Plasma ProUGN and ProGN were measured in 243 patients with chronic stable HF and plasma ProUGN and cGMP, an intracellular mediator of ProUGN activity, measured in 336 patients admitted to hospital with acute HF using immunoassays. ProUGN and cGMP levels were repeated in acute HF patients prior to discharge. The primary endpoints were all cause mortality, HF readmission and either outcome at 180 days. ProUGN and ProGN were significantly greater in patients with chronic HF compared to controls and inversely correlated with eGFR. ProUGN and ProGN were significantly greater in patients with hypertension and in those taking diuretics, with higher levels associated with increased severity of HF as assessed by NYHA class. In multivariate analysis, eGFR was the only independent predictor of plasma ProUGN and ProGN level. ProUGN and cGMP were significantly lower in patients with acute HF compared to in controls. Pre-discharge ProUGN and cGMP were significantly greater than at admission, with pre-discharge ProUGN significantly greater than in controls. Admission ProUGN was significantly greater in patients who died and a greater pre-discharge ProUGN was significantly associated with increased risk of early mortality. Pre-discharge cGMP levels were significantly lower in those readmitted with HF compared to those not, with higher levels significantly associated with reduced risk of early HF readmission. A greater pre-discharge ProUGN/cGMP ratio was significantly associated with increased risk of mortality or HF readmission. These results suggest that adverse outcomes in HF may be associated with hyporesponsiveness to ProUGN.

This thesis describes the development of a framework for computational modelling of electromechanics in the mouse, with the purpose of being able to integrate cellular and tissue scale observations in the mouse and investigate physiological hypotheses. Specifically, the framework is applied to interpret electromechanical coupling mechanisms and the progression of heart failure in genetically modified mice. Chapter 1 introduces the field of computational biology and provides context for the topics to be investigated. Chapter 2 reviews the biological background and mathematical bases for electromechanical models, as well as their limitations. In Chapter 3, a set of efficient computational methods for coupled cardiac electromechanics was developed. Among these are a modified Newton method combined with a solution predictor which achieves a 98% reduction in computational time for mechanics problems. In Chapter 4, this computational framework is extended to a multiscale electromechanical model of the mouse. This electromechanical model includes our novel cardiac cellular contraction model for mice, which is able to reproduce murine contraction dynamics at body temperature and high pacing frequencies, and provides a novel explanation for the biphasic force-calcium relation seen in cardiac myocytes. Furthermore, our electromechanical model of the left ventricle of the mouse makes novel predictions on the importance of strong velocity-dependent coupling mechanisms in generating a plateau phase of ventricular pressure transients during ejection. In Chapter 5, the framework was applied to investigate the progression of heart failure in genetically modified 'Serca2 knockout' mice, which have a major disruption in mechanisms governing calcium regulation in cardiac myocytes. Our modelling framework was instrumental in showing for the first time the incompatibility between previously measured cellular calcium transients and ventricular ejection. We were then able to integrate new experimental data collected in response to these observations to show the importance of beta-adrenergic stimulation in the progression of heart failure in these knockout mice. Chapter 6 presents the conclusions and discusses possibilities for future work.

Heart failure is a common condition in the Western world, particularly among elderly persons, and, with an ever-aging population, the incidence is expected to increase. Diet in the setting of heart failure is important—patients with this condition are advised to consume a low-salt diet and monitor their weight closely. Nutritional status of patients with heart failure is also important—those with poor nutritional status tend to have a poor long-term prognosis. A growing body of evidence suggests an association between heart failure and micronutrient status. Reversible heart failure has been described as a consequence of severe thiamin and selenium deficiency. However, contemporary studies suggest that a more subtle relationship may exist between micronutrients and heart failure. A small intervention study has suggested potential benefits of multiple micronutrient supplementation in patients with heart failure. The aim of this thesis was to examine the effect of a multiple micronutrient supplement in a larger group of patients with chronic stable heart failure. This was performed by conducting a randomized, double-blind, placebo-controlled trial. Seventy-nine patients with chronic stable heart failure were randomized to treatment with a multiple micronutrient supplement (Table 2.1) or placebo. The primary end-point of the study was left ventricular ejection fraction (TVEF), assessed using cardiovascular magnetic resonance imaging or 3-dimensional echocardiography. The secondary end-points were: quality of life (assessed using the Minnesota Living With Heart Failure Questionnaire), physical functioning (assessed using six-minute walk test distance), blood levels of N-terminal prohormone of brain natriuretic peptide, blood levels of C-reactive protein, blood levels of pro- and anti-inflammatory cytokines (tumour necrosis factor-alpha, interleukin-6 and interleukin- 10) and urinary levels of a marker of oxidative stress (8-iso-prostaglandin F2 alpha). All end-points were assessed at baseline and after 12 months of treatment with the study medication. Compliance with the study medication was assessed by measuring blood levels of a number of micronutrients contained within the multiple micronutrient supplement. In addition, all patients completed the European Prospective Investigation into Cancer and Nutrition Food Frequency Questionnaire at baseline and after 12 months of treatment with the study medication. Analysis of the food frequency questionnaire, completed at baseline, revealed evidence of high intakes of protein, carbohydrate and fibre and sub-optimal intakes of the micronutrients riboflavin, vitamin A, vitamin D, calcium, magnesium, zinc and selenium in this population. However, there was evidence of bias in reporting of dietary intake within the sample. Ninety-one percent of the population had evidence of vitamin D deficiency of sub- optimal status. Blood levels of ferritin, vitamin D, vitamin B6, pyridoxal, vitamin B12, folate and vitamin A increased significantly in the active treatment group relative to placebo, indicating good compliance with the study medication. There was no evidence of a large change in dietary intake over the course of the study. With respect to the primary end-point, complete follow-up data were available for 68 subjects (35 patients in the placebo group and 33 patients in the multiple micronutrient supplement group). There was no evidence of a significant effect of multiple micronutrient supplementation on LVEF. In addition, there was no evidence of a significant effect of multiple micronutrient supplementation on any of the secondary end-points. This study, therefore, provides no evidence to support the routine treatment of such patients with chronic stable heart failure with a multiple micronutrient supplement.

Stress (Takotsubo) cardiomyopathy is a severe form of acute heart failure (HF) with rapid onset, characterized by hypocontraction of the heart from the mid-left ventricle to apex. It is precipitated by extreme stress and plasma levels of the catecholamines adrenaline and noradrenaline are significantly elevated. This thesis describes the development of a new model of Takotsubo cardiomyopathy through rapid intravenous injection of a supraphysiological dose of adrenaline into anaesthetised male Sprague- Dawley (SD) rats and real-time imaging of the heart using either 2D-echocardiography or cardiac magnetic resonance (CMR). This in vivo rat model was used, in conjunction with in vitro IonOptix video-edge detection of cardiomyocyte contractility, to firstly demonstrate that this syndrome results from an adrenaline-induced trafficking-switch of the coupling of the pleiotropic β2-adrenceptor (AR) from Gs-adenylyl cyclase (AC)-cyclic adenosine monophosphate (cAMP) cardiostimulant to Gi-activated cardiodepressant pathways. Cardiomyocyte β2AR:β1AR population ratios, determined by radioligand binding, suggested that an apical-basal gradient in β2AR expression accounted for the in vivo apical hypokinesis. Certain β-blockers can act as biased agonists of a Gi-coupled isoform of the β2AR in animal and human cardiomyocytes via a pathway that involves p38 MAPK. Administration of the clinical β-blockers propranolol and carvedilol 15 minutes after adrenaline either enhanced or failed to reverse apical hypocontractility. In vitro analysis demonstrated that β2AR-Gi signalling involves p38 MAPK activation. However, pre-treatment with either the p38 MAPK inhibitor SB203580 or the β2AR blocker ICI-118,551 prior to adrenaline resulted in significant mortality, which suggested that the β2AR-Gs/Gi coupling switch is a cardioprotective strategy. Gi-protein is upregulated in chronic HF, while β1ARs are down-regulated. In contractility studies of chronically failing human/rat cardiomyocytes, β2AR-Gs responses were present with minimal active Gi-protein component. This suggested that while in acute HF β2AR-Gs positively inotropic responses are impaired and β1ARs are preserved, the opposite may be true in chronic HF.

This thesis studies techniques for maximising the effects of Cardiac Resynchronisation Therapy (CRT) which is a modern therapy for chronic heart failure. The ability of echocardiographic parameters of mechanical dyssynchrony to identify suitable candidate patients for CRT, and subsequently to optimise the interventricular delay, is disputed. In this study, I initially perform a systematic review to clarify the nature and extent of this problem. I then perform detailed mathematical simulations to understand what is feasible in an ideal setting. I then evaluate the realistic potential of several non-invasive approaches of optimising CRT devices by formal evaluation head-to-head. A fundamental requirement for any marker in optimisation of CRT devices, or in selection of patients for implantation, is that the marker must be reproducible and must change when the amount of dyssynchrony changes. I perform detailed experiments in patients where I interrogated a panel of echocardiographic parameters to answer the questions relating to the sensitivity of each parameter and looked at methods to improve this. I look at the effect of spontaneous variability, and the impact on each echocardiographic method including 3D echocardiography, tissue Doppler imaging and pulsed Doppler techniques including velocity time integrals and pre-ejection times. Finally, I perform an invasive study of the beat to beat physiological changes which occur after intra cardiac timings are altered, to evaluate alternative approaches to changes in cardiac performance that might be easier to automate.

Sustained injury of the myocardium can lead ultimately to heart failure. The restricted ability of the heart to repair after injury is due to inherent limited regenerative capacity of the bi-nucleated adult cardiomyocyte. A long sought goal has therefore been to identify approaches that facilitate cardiomyocyte proliferation and regeneration. CDKN1A interacting zinc finger protein 1 (CIZ1) is an alternatively spliced gene that has been shown to play a role in mammalian DNA replication in vitro. Full length CIZ1 protein localises to dynamic sub-nuclear foci, with co-localisation experiments suggesting significant association with DNA replication factories and active DNA synthesis. CIZ1 interacts directly with key regulators of the cell cycle, including Cdk2, cyclin E, cyclin A, and Cdk2 inhibitor p21. CIZ1 (and many of its splice variants) have been linked to a number of proliferative disorders, ranging from rheumatoid arthritis to cancer. In addition to actively proliferating cells, CIZ1 foci can be detected in terminally differentiated cells including adult cardiomyocytes. However, expression of new Ciz1 product at the mRNA level is very low in these cells, compared to non-myocyte cells of the heart. It is currently unclear whether the remaining protein retains function or is a remnant of the final round of cardiomyocyte DNA replication leading to the quiescent bi-nucleated state. This study aimed to investigate whether CIZ1 is a suitable candidate molecule for stimulating cardiomyocyte regeneration to aid restoration of normal heart function through re-establishment of cardiomyocyte self- renewal capacity. A conditional transgenic mouse model, in which CIZ1 is over- expressed specifically in cardiomyocytes has been generated. Transgenic hearts are enlarged due to cardiomyocyte hyperplasia, although Millar catheter assessment showed no evidence of cardiac dysfunction. Individual cardiomyocytes isolated from transgenic hearts exhibit altered nuclear dynamics, with a significant increase in the number of mono-nucleated cells relative to bi-nucleated. Furthermore, preliminary data using in vivo EdU DNA replication assays showed evidence of cell cycle reactivation in the transgenic hearts. Up-regulation of genes involved in G1 and G1/S phase transition has also been indicated. The results suggest that CIZ1 may be a suitable novel candidate for therapeutic application in cardiac regeneration following injury.

Cardiovascular disease is a leading cause of death worldwide and becomes increasingly prevalent in the elderly population. Independent of etiopathogenesis, heart failure (HF) is the final common stage of numerous heart diseases. Cardiac stem cell (CSC) therapy has emerged as a promising cell-based strategy for treatment of HF. However, cell replacement is not able to fully restore a structurally damaged myocardium in advanced and end-stage HF. The objective of this project was to test the following hypotheses: that a bioengineered heart extracellular matrix (ECM) with preserved intact geometric structure could be generated using decellularization by coronary perfusion; and that autologous CSCs, to repopulate this ECM, could be isolated and expanded from the adult heart, with the caveat that autologous CSCs are depleted and impaired by both aging and chronic dilated cardiomyopathy. This will help to develop a possible therapeutic approach for advanced HF, using a combination of CSCs and engineering technique. Resident CSCs were isolated from explant-derived cells (EDCs) and expanded into cardiosphere-derived cells (CDCs) via cardiosphere formation. The CDCs expressed CSC markers (c-kit and Sca-1), pluripotent markers (Oct3/4 and Sox2), and the cardiac lineage-committed marker (Nkx2.5), and showed clonal expansion, self-renewal, and cardiomyogenic potential in vitro. In tissue engineering experiments, CDCs survived and proliferated within biomaterial alginate scaffolds for up to 7 weeks. An engineered bioartificial ECM scaffold was successfully produced from a whole rat heart using retrograde coronary perfusion and possessed an intact 3D architecture with functionally perfusable vascular network. Compared with ventricles, cultures derived from atria produced significantly higher number of c-kit+ and Sca-1+ CSCs (c-kit: 13% vs. 3.4%; Sca-1: 82% vs. 53%, respectively) and exhibited greater clonogenic and proliferative capacity. CDCs could be grown from young and aged mice, but the yield of CSCs significantly declined with age, as did cell migration and differentiation potential. In comparison to wild-type mice, atrial-CDCs from dystrophic mice showed no significant differences in CSC subpopulations and characteristics, despite confirmation of cardiac dysfunction using MRI. In conclusion, CDCs could be considered to be a viable cell candidate for cardiac therapy and may be used to treat HF at various stages, in combination with myocardial tissue engineering.

Heart failure (HF) is a common, disabling and deadly condition that causes high rates of morbidity and mortality worldwide. It is widely recognised that the failing heart is energy-starved, and that restoring energy homeostasis is a promising approach towards improving cardiac output. This thesis aims to address the role of energetics in the failing heart, by focussing on modulation of the creatine transporter (CrT). Creatine (Cr), together with the phosphocreatine shuttle, plays a vital role in maintaining energy supplies via ATP in times of high energy demand. Key to the regulation of intracellular [Cr] is the CrT, a Na+ and Cl- - dependent membrane transporter. Previous CrT genetic mouse models include a knockout model, found to still express cardiac CrT, and a cardiac-specific CrT overexpressing (OE) model with large variations in myocardial [Cr] between animals and Cr levels high enough to cause spontaneous hypertrophy. To overcome the shortfalls of this CrT-OE model, a novel in vivo model of temporal inducible expression of CrT is described, using a cardiac-specific tetracycline inducible (Tet-On) system. Ten transgenic lines (RCT) were created with a construct containing the CrT-HA (CrT cDNA with an haemagglutinin epitope tag), following successful doxycyline-inducibility in vitro. Eight lines showed germline transmission, with LV CrT OE achieved in an individual mouse that displayed double LV [Cr] compared to WT. Issues with the inducer line (rtTA) were ruled out by its use in the creation of a luciferase overexpressing mouse line; all mice tested demonstrated LV luciferase expression in response to doxycycline feeding. The failure to overexpress CrT could be attributed to position or copy number dependent suppression, or to position effect variegation in the case of the single OE mouse obtained. Subsequent work focussed on regulatory pathways in vitro in a cell line of mouse fibroblasts stably overexpressing CrT-HA. Post-translational modifications (PTMs) had been previously suggested to regulate CrT activity. Two N-linked glycosylation sites exist, in addition to the putative phosphorylation sites. Inhibition of glycosylation by tunicamycin led to decreased CrT activity, reflected by decreased Cr uptake capacity. Strategies to confirm the presence of phosphorylation were employed, including isolation of CrT-HA by immunoprecipitation and subsequent LC-MS / MS analysis to identify PTMs. Although the presence of CrT was confirmed in 5 different sized species- one previously unreported- inadequate sequence coverage prevented identification of any PTM sites. Tyrosine phosphorylation was not detected using a phosphospecific antibody on immunopurified CrT-HA. Candidate signalling pathways in vitro were then investigated to elucidate CrT regulation, namely the IGF 1R signalling pathway. This study included a cardiomyocyte-like mouse cell line (HL-1) in addition to 3T3-CrT-HA. Exposure of cells to extracellular insulin, growth hormone and IGF-1 led to increased Cr uptake of 125% - 300% of normal. Pharmacological inhibition of the downstream kinases PKA and PKC reduced the effect of insulin and GH, while PMA, sapintoxin (STX) and Gö 6976 induced CrT activity. The mammalian target of rapamycin (mTOR) is also a candidate regulator of CrT, as incubation with rapamycin decreased Cr uptake in 3T3-CrT-HA. Finally, a targeted approach on transcription factors in the 5'UTR region of mouse CrT identified HEY1 as a highly conserved site. In siRNA experiments, HEY1 was found to exert a mild effect on CrT activity, suggesting that regulation at the transcriptional level merits further investigation. Together, this work has provided novel insights into the modulation of CrT in vitro, identifying molecular and pharmacological targets in a known therapeutic signalling pathway. Further work could potentially develop these findings by identifying candidate compounds that would increase CrT activity, potentially in a tissue-specific manner.

Heart failure is a very common medical condition with significant mortality and morbidity. Patients hospitalised with heart failure are at high risk of death in the short term and patients with chronic heart failure in the community are also at a high risk of death in the medium to long term. It is difficult to accurately identify those at a higher risk of death as current methods of risk stratification lack both sensitivity and specificity. The available treatments for prevention of sudden death in patients with heart failure such as Implantable Cardioverter Defibrillators (ICD) are expensive and do not abolish the risk of sudden death completely. Hence it is necessary to improve risk stratification methods in patients with heart failure and identify factors predicting mortality in those patients with ICD protection. This thesis first describes a series of studies examining the clinical factors that predict increased risk of short-term mortality in patients with a recent hospitalisation for heart failure. These include examination of patient demographics, clinical history and examination, blood tests, electro-cardiographic and echo-cardiographic variables and medication. Based on these variables, I have formulated a simple scoring system to predict short term mortality in hospitalised patients with heart failure. This score was validated in a prospective study of contemporary heart failure population with a recent hospital admission. The relationship of cholesterol and risk of death in heart failure was examined in detail. Then, the utility of Holter monitoring and signal averaged electro cardiograms (SAECG) for risk stratification were examined based on the prognostic value of abnormalities found by these tests in patients with chronic heart failure. Finally patients with heart failure deemed at high risk of sudden death and had ICDs implanted were studied and factors predicting shocks and mortality were identified. Two separate studies were done, first in population who had ICDs mainly for secondary prevention and the second in patient population who had ICDs exclusively for primary prevention. From these studies, I have identified those clinical characteristics that are associated with high risk of death in patients with acute and chronic heart failure and those associated with death in patients with heart failure after ICD implantation.

Introduction: Robust epidemiological data on the incidence of myocardial infarction (MI) are hard to find, but synthesis of data from a number of sources indicates that the average hospital in the UK should admit about two patients with a first MI and one recurrent MI per 1000 population per year. Although age-adjusted incidence may be declining, this may be offset by greater longevity in the general population. The incidence of acute coronary syndromes (ACS) is much higher. The incidence and outcome of both ACS and of MI will depend greatly on how data are collected. The cumulative incidence, persistence and resolution of heart failure (HF) after an MI in the general population are poorly described. Cardiac dysfunction subsequent to MI is a common cause for morbidity and mortality, however, there are few data on what proportion of longterm survivors of MI has important cardiac dysfunction and/or HF. The aim of this thesis is to describe the incidence and outcome of MI in the general population and in different age groups, explain the natural history and prognosis of HF after an MI both during the index admission and long-term (6 year) follow-up in relationship to the presence of HF and also to determine the utility of amino-terminal pro-brain natriuretic peptide (NT-proBNP) alone and in conjunction with other clinical data, as a marker of left ventricular systolic dysfunction (LVSD) and subsequent prognosis in long-term survivors of MI. Subgroup data according to age and anaemia will also be reported. Methods: Patients with a death or discharge diagnosis of MI in 1998 were identified from records of hospitals providing services to a local community of 560,000 people. Records were scrutinized to identify the development of HF, defined as symptoms and signs consistent with that diagnosis and treated with loop diuretics. HF was considered to have resolved if diuretics could be stopped without recurrent symptoms. Analyses were done on the whole population and then sub-groups by age (75 years) and anaemia status. Anaemia was defined according to WHO criteria (men haemoglobin (Hb)1 g below threshold), borderline (within 1g of threshold) and (>1g above threshold). In 2004, surviving patients were invited to attend for clinical assessment, an echocardiogram and measurement of NT-proBNP and were subsequently followed until 31st December 2009 using medical records. Also in 2005, another group of patients admitted with ACS to cardiology or general medical wards were identified prospectively by trained nurses from 1st January to 31st December 2005. Patients with a death or discharge code of MI were also identified by the hospital information department and from Myocardial Infarction National Audit Project (MINAP) records. Results: For the first cohort, 896 patients were identified of whom 54% had died by December 2005. During the index admission, 199 (22%) patients died, many with HF, and a further 182 (20%) patients developed HF that persisted until discharge, of whom 121 died subsequent to discharge. Of 74 patients with transient HF that resolved before discharge, 41 had recurrent HF and 38 died during follow-up. After discharge, 145 (33%) patients developed HF for the first time, of whom 76 died during follow-up. Overall, of 281 deaths occurring after discharge, of which 235(84%) were amongst patients who first developed HF. Of 896 patients, 311 were aged 75 years of whom, respectively, 24%, 57% and 82% had died by December 2005. During the index admission, by age group, 24 (8%), 68 (23%) and 107 (37%) patients died in each group, many with HF, and a further 37 (12%), 63 (21%) and 82 (29%) developed HF that persisted until discharge. After discharge, 53 (24%), 55 (40%) and 37 (47%) patients developed HF for the first time. Overall, of 51, 102 and 128 deaths occurring after discharge, 35 (70%), 93 (91%) and 107 (85%) were among patients who first developed HF. Of 855 patients with an available hemoglobin during index admission, 103 were anaemic, 280 were borderline and 472 were not anaemic based on the first available haemoglobin during the index admission. 300 patients had more than one measurement of haemoglobin, of which 125 (85 unchanged status from first assessment) had definite, 289 (237 unchanged) had borderline and 441 (424 unchanged) had no anaemia on the last available measurement. During the index admission, 77 patients (75%) with definite, 130 (46%) with borderline and 196 (42%) who had no anaemia on the first available haemoglobin developed HF, of whom 41 (53%), 50 (38%) and 60 (31%) died during the admission compared, respectively, to 7 (27%), 14 (9%) and 9 (3%) deaths in patients who did not develop HF. During a six year follow-up, 543 (64%) patients developed HF and 456 (53%) died. Amongst patients with HF during the index admission, the six year mortality rates in those with definite, borderline and no anaemia (last available index admission measurement) were, 90%, 84% and 64% (P=0.0001). In patients without HF on the index admission, 6-year mortality rates were 62%, 42% and 24% (P=0.0001). Anaemia (last available index admission measurement) predicted all-cause mortality independent of the presence of HF (p=0.055). 451 had died by 2004 and only 414 were available for follow-up, of whom 175 patients attended and had NT-proBNP measured. Of these, 51 (29%) patients had LVSD, 66 (38%) had NT-proBNP >50pmol/L (423pg/ml), 86 (49%) had one or the other and 31 (18%) had both. Patients with higher NT-proBNP were more likely to have HF (and be treated with diuretics), LVSD (and therefore treatment with ACE inhibitors), a dilated atrium, substantial mitral regurgitation and atrial fibrillation (and therefore treatment with warfarin and digoxin) (p=0.0001). Thirty six patients died during follow-up; 28 (42%) with an NT-proBNP >50pmol/L (423pg/ml) (77% of all deaths). ROC curves suggested that NT-proBNP 56pmol/L (474pg/ml) had the highest sensitivity (78%) and specificity (77%) for predicting death (AUC 0.78). Echocardiography added little to the prognostic information provided by NT-proBNP alone. In 2005, the prospective survey identified 1,731 admissions (1,439 patients) with ACS, of which 764 (704 patients) were for MI. The hospital information department reported only 552 admissions (544 patients) with MI and only 206 admissions (203 patients) were reported to MINAP. Using all three data-bases, 934 admissions (873 patients) for MI were identified, for which TnT was >1ug/L in 443, 0.04 to 1.0 in 435, 0.03ug/L but did not have ACS ascertained by any survey method. Of 873 patients with MI, 146 died during admission (17% versus 22% in the 1998 cohort) and 218 by one year. Conclusion: The incidence of ACS/MI is highly dependent on the methodology for case-ascertainment and the method used to identify cardiac damage (for instance the sensitivity of the troponin assay used). The development of HF precedes death in most patients who die in the short- or longer-term following an MI. The risk of developing HF and dying after an MI increases progressively with age and anaemia. In patients with a remote history of MI, elevated NT-BNP identifies patients with a high prevalence of LVSD. Regardless of age, most deaths are preceded by the development of HF. Anaemia is associated with a high mortality even in the absence of HF. Prevention of HF, by reducing the extent of myocardial damage and recurrent MI and by subsequent good management could have a substantial impact on prognosis.

Coping is acknowledged to be an important factor in the process of adjustment to illness, and which has consistently been related to outcomes in chronic health conditions such as heart failure (HF). Despite this, to date coping has been poorly conceptualised which has limited the clarity and usefulness of research findings. A systematic review was conducted to examine the relationship between ways of coping, and dimensions of psychological wellbeing as important health outcomes in the HF population. Electronic databases (CINAHL, Medline, PsychINFO, Scopus and Web of Science) were searched and articles selected based on systematic search, inclusion and exclusion criteria. Sixteen studies were included in the review utilising a variety of designs and measures. Study findings suggested that coping by ignoring, minimising or denying HF is related to poorer outcomes of psychological wellbeing. However, more illness focused ways of coping did not consistently relate to better outcomes. Consistent with research in other populations, the conceptualisation of coping in the reviewed studies was inconsistent. It is argued that coping should be considered within a wider framework of transition and adjustment to more meaningfully examine HF patients‟ experience following diagnosis and inform more appropriate psychological support strategies.

People with heart failure frequently experience poor quality of life, often exacerbated by co-morbidities. This demands complex self-management activities, often supported by family members in care roles, and includes input from community Heart Failure Specialist Nurses (HFSNs) that is known to reduce hospital readmissions. There is, however, a paucity of knowledge about the perceptions of people living with heart failure concerning self-management strategies. Aim This thesis is a longitudinal study exploring emergent patterns and styles of self- management of persons with heart failure, the impact of family members and HFSNs. Method Thirty-one theoretically sampled participants with heart failure were recruited from a district general hospital between October 2004 and September 2006. The sample participated in home-based, audio-taped, semi-structured interviews prior to nurse intervention, describing how heart failure affected their lives, focusing on self-management strategies. The HFSNs conducted home visits and telephone contacts according to individual needs independent of the research. At five months, 23 participants completed a diary for 14 days. Twenty- seven participants (three died, and one withdrew) were interviewed at six 3 months to explore how self-management strategies had changed. The HFSNs participated in a focus group. Constructivist grounded theory and reflexive accounting informed data collection and analysis, leading to the inductive development of an explanatory framework for emergent themes, one of which, Informed Support, serves as an original and significant contribution to the literature. Results Successful management is a complex biopsychosocial activity, involving reconstructions of identity, symptom management, and relationship management, while living with a chronic and uncertain condition that severely compromises life activities. Central to successful management is Informed Support, where family members collaboratively develop a range of activities and attributes to augment self-management. This was perceived as most effective when the HFSNs were able to adopt a 'whole family' approach. Conclusion Heart failure self-management is a dynamic, complex and adaptive activity that can be positively and significantly shaped by Informed Support from family members. Community based HFSNs can influence, but need to recognise differing styles of, self-management.

Cardiac fibroblasts play an important role in the function of the myocardium by regulating the extracellular matrix of the heart. Changes in the function of cardiac fibroblasts are a feature of heart failure. A subset of patients with heart failure that receive Left Ventricular Assist Devices, in combination with pharmacological therapy, are able to recover cardiac function to the point that the devices can be explanted. The response of cardiac fibroblasts to a combination of unloading and the pharmacological therapy given to these patients, which includes the Β₂-adrenoceptor receptor (Β₂-AR) agonist Clenbuterol, may play an important role in the reverse remodelling process. This thesis focuses on the response of cultured cardiac fibroblasts to Clenbuterol and mechanical stretch.

CHF is a complex disease that results in the remodelling of the heart at every level, from the gross anatomy down to the levels of the ion channel resulting in aberrant signalling and contractile dysfunction. The QT interval of the cardiac ECG is frequently increased in heart failure, suggesting ion channel remodelling which has proarrhythmic consequences. One of the aims of this study was to determine the changes that occur from the in vivo level, down to the level of the ion channel that may contribute to arrhythmogenesis.

The role of the plasma membrane calcium ATPase (PMCA), a calcium extruding enzyme, in cardiac physiology is not yet entirely clear. Two isoforms of PMCA, PMCAl and 4, are expressed in the myocardium. In the heart PMCA had originally been thought to play a rather minor role in cardiac relaxation. However, our group has suggested a new function for PMCA4b as a modulator of signal transduction pathways through its interaction with neuronal nitric oxide synthase (nNOS) in a cellular model; however, the role of the PMCA4-nN0S complex in the heart is still unclear. In addition, the differential role of the isoforms 1 and 4 remained enigmatic. The aim of the current study was to investigate the molecular mechanisms by which PMCA isoforms (1 and 4) modulate cardiac contractility.

Aims: The main objective of this research was to determine if Type D personality predicts distress in Heart failure (HF) patients. The study also sought to examine whether there is a relationship between Type D personality, coping and psychological distress in this cardiac patient group. Method: A cross-sectional, quantitative design was used. 72 (58 %) with HF between September 2005 and March 2006 completed questionnaires in the outpatient clinic of a cardiology department. The DS14 questionnaire was used to measure Type D personality (predictor variable), the Hospital Anxiety and Depression Scale (HADS) measured psychological distress (outcome variable) and the Brief COPE inventory was the measure of coping used (mediator variable) of this HF patient sample. Main analyses: An ANOVA test investigated whether Type D predicted distress. The mediational regression model (National Institute for Clincial Excellence, 1986) was used to analyse the relationships between the three variables. Results: Type D significantly predicted depression (p

Characterisation of ventricular activation through conventional mapping techniques has always been limited by the need for sequential mapping which is unsuitable for non-sustained or poorly tolerated rhythms. Non-contact mapping, with its ability to generate simultaneous, high resolution. isopotential maps from an entire cardiac chamber, enables characterisation of cardiac activation in the intact human heart to a detail not previously attainable. Characterisation of properties of the excitable gap of ventricular tachycardia (VT) circuits was performed by analysing the response to single programmed extrastimuli in an attempt to reset the circuit. The temporal and spatial properties of the EGap vary at different sites of entry to the circuit. The effects of single ventricular extrastimuli (SVE) preexciting such circuits are dependent on the degree of interval dependent conduction slowing (conduction in partially excitable myocardium) within the diastolic pathway or modification of functional block defining the circuit. All circuits could be preexcited over a range of SVE's, therefore failure to reset a tachycardia does not indicate the absence of an excitable gap and failure of entry to the circuit. Mapping and ablation of VT circuits was performed in 40 patients all with previous myocardial infarction. Non-contact mapping identified an exit site in 100% and diastolic pathway activity in 56% of VT and guided successful ablation in 88% of patients. VT recurrence necessitating ICD therapy was significantly reduced but new VT is seen probably reflecting the evolving underlying substrate. Using non-contact mapping, VT, exit site location was identified in 121 VT and compared with 12 lead ECG morphology during VT. A correlation, a positive predictive value of ~70%, was seen with 8 different ECG patterns, accounting for 57% of mapped VT. An algorithm was developed and tested prospectively which led to correct identification of 93% of VT exit sites. Non-contact mapping was used to characterise the timing and patterns of activation in 41 patients with remote myocardial infarction and impaired left ventricular function. Eighteen patients had normal QRS duration and 23 had left bundle branch block (LBBB). In patients with LBSB, the principal cause of QRS prolongation is not due to increased interventricular conduction but to increased intraventricular LV conduction time. Lack of benefit from cardiac resynchronization seen in a subset of patients may be due to this intraventricular conduction delay. Although ECG characteristics of LSBS do not correlate with sites of earliest or latest endocardial ventricular activation, they do identify a subset of patients with the longest intraventricular conduction delay.

Objectives: To examine the impact of a specialist nursing intervention upon the illness representations, self-reported medication adherence, attitudes towards medication and psychological morbidity of heart failure patients. Design: A longitudinal study following a cohort of community based participants who had been previously hospitalised with heart failure over a three month time interval. Method: A total of 28 heart failure patients participated in the study. Participants completed a demographic questionnaire, the Illness Perception Questionnaire (IPQ), the Medication Adherence Report Scale (MARS), the Beliefs About Medicines Questionnaire-General Version (BMQ-G), the Beliefs About Medicines Questionnaire-Specific Version (BMQ-S), the Hospital Anxiety and Depression Scale (HADS) and the Significant Others Scale-Form B (SOS-B) at two interviews. Comparisons of data within the group at the two time points were undertaken. Results: Analysis revealed no statistically significant differences within the group from time one to time two of the nursing intervention in illness representation, self reported medication adherence, attitudes towards medication or physiological morbidity. The exception to this was a significant difference on the BMQ-S subscale, necessity. Between time one and time two participants' beliefs in the necessity of their medication had significantly reduced. Conclusions: Whilst specialist nursing interventions have significantly reduced hospital readmissions, no significant psychological impact of this programme was detected. The potential reasons for the lack of significant results as well as the clinical implications of the findings are explored. The value of routine assessment of psychological morbidity in this population is discussed.