Cardiomyopathies are heart muscle diseases associated with cardiac dysfunction and fibrosis. [1, 2] Formation of scar tissue increases the likelihood of ventricular arrhythmia (VT/VF), the final common pathway in the majority of sudden cardiac death (SCD). Diagnosis of inherited cardiomyopathies can be challenging particularly in the early stages of disease. Although implantable cardioverter defibrillator (ICD) therapy reduces SCD due to VT/VF, risk stratification in both acquired and inherited cardiomyopathies is imperfect. [3, 4,5,6] There are up to 100,000 SCDs each year in the UK.[7] Ventricular ectopic beats (VEB) are conducted through myocardium with limited participation of specialized conduction tissue and may therefore provide an index of the state of the myocardium, extent of fibrosis and risk of SCD.[8] Aims: to develop novel VEB electrocardiographic indices to aid cardiomyopathy diagnosis and risk stratification. Methods: 12 lead Holter monitoring to examine novel VEB indices: the ventricular ectopic QS interval (VEQSr); the number of VEB morphologies; and VEB fragmentation in cohorts of normal controls and patients with inherited and acquired cardiomyopathies. Relationship of the novel VEB indices with structural heart disease was assessed using echocardiographic and cardiac magnetic resonance imaging. Novel VEB indices were compared between cohorts and in patients with and without prior cardiac arrest. These indices were compared with conventional diagnostic and risk stratification criteria using multivariate analysis. Results: Normal ranges for novel VEB indices were defined in normal controls with good interobserver reproducibility. Novel VEB indices were significantly greater in patients with cardiomyopathy than normal controls and VEQSI in particular correlated with structural abnormalities. VEQSI appears more useful than VEB morphologies and VEB fragmentation in providing incremental information in the diagnosis of arrhythmogenic right ventricular cardiomyopathy and risk stratification of ischaemic cardiomyopathy. Novel VEB indices and myocardial deformation imaging suggest subtle underlying biventricular structural disease in Brugada syndrome. Conclusions: These novel VEB electrocardiographic indices are promising markers for diagnosis and risk stratification in inherited and acquired cardiomyopathies and require further assessment with larger patient numbers and prospective follow up.

BACKGROUND: Sudden cardiac death (SCD) in any young person is a tragic event with a significant number of life-years lost. Previous data from Italy suggest that pre-participation screening using an electrocardiogram (ECG) reduces the incidence of SCD in competitive athletes. However, the majority of SCD occurs in non-athletes within the general population. In the United Kingdom, state sponsored screening for cardiac disorders is confined to symptomatic individuals or those with a family history of inherited cardiac conditions or premature cardiac death. AIMS: To assess the feasibility and efficacy of screening, incorporating an ECG and point-ofcare echocardiography, in young individuals from the general population for cardiovascular conditions associated with SCD. METHODS: Between 2008-2012, 10,359 young individuals aged 14-35 years underwent screening by an attending cardiologist comprising a health questionnaire, physical examination and ECG. ECGs were analysed in accordance with the European Society of Cardiology (ESC} recommendations for ECG interpretation in athletes for Group-1 (trainingrelated) and Group-2 (potentially pathological) patterns. Group-2 ECG patterns warrant further cardiac evaluation. Individuals with findings raising suspicion of cardiomyopathy underwent on-site echocardiography. Individuals with abnormalities from the screening episode were referred for further evaluation for conditions associated with SCD and followed up annually to assess outcomes. Based on these data comparisons of the efficacy of different screening strategies were made and costs and cost effectiveness were calculated. RESULTS: Symptoms of a cardiovascular nature were reported in 44.2% of individuals, a family history of SCD or condition associated with SCD was reported in 3.8% and an abnormal physical examination occurred in 0.3% of individuals. ECG patterns suggestive of cardiac pathology were identified in 22.4% of individuals, predominantly due to abnormalities of QTc measurement. Male gender and black ethnicity demonstrated the strongest association with ESC Group-2 ECG patterns. Point-of-care echocardiography for individuals with suspicion of cardiomyopathy significantly reduced the number of patients requiring further evaluation as only 14.8% of these individuals demonstrated abnormal echocardiographic findings. Positive diagnosis of a cardiovascular condition associated with SCD was identified in 0.3% of individual;; (cardiomyopathy, n=6; primary electrical disease, n=17; Marfan syndrome, n=4). This screening strategy demonstrated a sensitivity of 100%, specificity of 93.2% and false-positive rate of 6.8% with an estimated cost of £106,141 per diagnosis made. CONCLUSIONS: Screening for conditions associated with SCD in the general population is feasible. A screening strategy incorporating the ECG and point-of-care echocardiography is associated with a high sensitivity and specificity and low false-positive rate as well as favourable cost analyses.

Sudden cardiac death is the second biggest cause of death in the UK and at least 12 young people aged 14 to 35 die each week from undetected cardiac conditions. Cardiac screening, 12-led ECG test, has been speculated to have 90% effectiveness for illness detection. The UK National Screening Committee does not mandate population screening because there is not enough evidence for the cost-effectiveness and psychological costs to the individual. Yet, measuring the effectiveness of a screening relies on its participants. Literature to date offers some explanations for participation and non-participation; however, there is no literature for parents' decision-making processes for cardiac screening for adolescents aged 14-17. Therefore, this research has emerged from the need to understand the cognitive and affective processes that explain the decisions whether or not to take part in cardiac. screening. In pmiicular, Weinstein's (1988) Precaution Adoption Process Model (P APM) is used to identify of the stages of engagement for a non-apparent, a relatively unknown health risk, and investigated role of affect in decision-making. Initially, we explored retrospective accounts of non-pmiicipant families with a qualitative study and found that parents m·e primary decision-makers and organisations providing screening have a fundamental role for communicating credibility, task impOliance and salience under unceliainty. FUlihelIDore, we have explored decision-making with a concurrent think aloud study and found that "feelings-of-risk" provide a first step in engagement with health risk. Collectively, we assessed these findings with a prospective mixed methods study in which parents of adolescents were staged according to P APM. The results indicate that the respondents' trust and confidence in the organisation and the screening procedure provides the first steps from being unaware, unengaged and needing more information whilst "feelings-of-risk" is integral for deciding whether or not to have screening. The reasons for non-pmiicipation is characterised as being unfamiliar (unaware), having low trust in the processes of the organisation (unengaged), low decisional certainty (need info), low concern (not intend) and having practical baniers (non-pmiicipant intenders). The implications ofthe results are considered for theory, research and practice.

Introduction Cardiovascular disease remains the commonest cause of death in the western world with an estimated 50% of deaths occurring suddenly. Efforts to improve survival from sudden cardiac arrest (SCA) have focused on dissemination of automated external defibrillators (AEDs) and improvements in cardiopulmonary resuscitation (CPR). However survival from SCA remains poor (5- 10%) and new developments to refine and improve defibrillation strategy and CPR are required. Aims To investigate the impedance cardiogram (ICG) measured via defibrillator pads as a marker of chest compression efficacy during cardiac arrest and as a haemodynamic indicator during cardiac arrhythmia To investigate ventricular fibrillation (VF) waveform characteristics for prediction of defibrillation success Method A porcine model of cardiac arrest was performed with simultaneous measurement of ICG, mechanical and physiological indicators of efficacious CPR. A subsequent pilot study of cardiac arrest patients was performed with simultaneous ICG and compression depth measurements. Two studies of the ICG during cardiac catheterisation and electrophysiology studies were performed with simultaneous measurement of ECG, ICG and arterial blood pressure. A retrospective analysis of VF waveform characteristics in 44 patients suffering VF cardiac arrest was also performed Results The pre-clinical study confirmed strong correlations between ICG amplitude and mechanical and physiological indicators of chest compression efficacy. The subsequent pilot study confirmed the ICG as an accurate measure of compression rate but not depth. Analysis of the ICG during catheterisation studies confirmed circulatory and ventilatory waveform components but no feature accurately differentiated haemodynamic status. VF waveform analysis confirmed that AMSA and Slope most accurately predicted shock success with improved predictive performance using a Support Vector Machine (SVM) approach. Conclusion The combined studies investigated novel impedance and electrocardiogram analysis during cardiac arrest and demonstrated their potential to enhance AED functionality, improve CPR performance and optimise defibrillation to improve resuscitation outcome

Although traditionally vjewed as separate disease entities that increase in prevalence with aging, accumulating evidence indicates that similar pathophysiological mechanisms underlie cardiovascular disease and osteoporosis. This evidence has both clinical and biochemical foundations, however the complex interaction of common risk factors and genetic or molecular determinants; requires further research to clearly define these mechanisms. Nitrogen containing bisphosphonates inhibit the isoprenoid biosynthetic enzyme, farnesyl diphosphate (FFP) synthase, in the same cholesterol biosynthesis pathway as statins. Inhibition of FFP synthase leads to loss of farnesylation and geranylation of small GTPase proteins. Statins have been shown to exert cholesterol-independent vaso-protective effects mediated, through inhibition of these small GTPase proteins, Rho and Rac. By inhibIting both Rho and Rac GTPase activity via inhibition of geranylgeranylation, endothelial nitric oxide synthase (a vasodilator) is up-regulated and superoxide (a vasoconstrictor) production is decreased. Although it has been previously been considered that current dosing regimens and low absorption have resulted in a low body "burden" of N-BPs, an expanding body of evidence would suggest that considerable work is still required to fully elucidate the effect of these drugs beyond the bone matrix. Endothelial dysfunction is the initial step in the atherosclerotic process. This thesis aims to determine if women with post-menopausal osteoporosis have impaired endothelial function and if treatment with Risedronate over a 24 week period has an influence on non-invasive vascular measures of endothelial function. We examine both peripheral and central arterial beds, using well established non-invasive methods to obtain a global measure of endothelial function. We employ novel methods of flow velocity waveform analysis to extract potentially meaningful differences in arterial flow waveforms that would indicate subclinical vascular disease.

The transient receptor potential (TRP) Ca2+ permeable cation channels enable cells to respond directly to a variety of changes in their local environment. There is a growing body of evidence implicating TRPs in a variety of diseases, including endothelial dysfunction and cardiovascular disease. However, the expression profile and functional roles of TRPs in the human vasculature remain poorly characterised. This thesis was split into two main chapters to investigate expression and function of two separate TRP channels in endothelial cells. The first part concentrated on the evidence for a functional role for TRPM8 in endothelial cells and the second part investigated changes in expression and functional roles of TRPV4 in endothelial cells in hyperglycaemic conditions and in diabetic blood vessels from streptozotocin (STZ) injected rats. Patch-clamp, Ca2 + imaging and cell growth ass;3ys revealed functional expression and an important role for TRPM8 in endothelial physiology; immunocytochemistry and Western blot also confirmed plasma membrane and perinuclear bound TRPM8 protein expression ih these cells. However conventional PCR and qRT-PCR were unable to confirm TRPM8 mRNA expression. Hyperglycaemia in human aortic endothelial cells (HAoEC) lead to down-regulation of TRPV4 mRNA which was also seen in whole aorta, mesenteric artery, renal artery and retinal arterioles from STZ injected diabetic rats, as examined by qRT-PCR. Ca2+ Microfluorimetry studies revealed that TRPV4 mediated Ca2+ entry was down-regulated in HAoEC after 72 hour exposure to high D-glucose. Further work is required to elucidate the functional expression of TRP channels in the vasculature and to determine their role in the pathogenesis of endothelial dysfunction and associated cardiovascular disease.

Diet is recognised as a modifiable risk factor for cardiovascular disease (CVD). Dietary exposure can be examined through assessment of dietary intake or examination of nutrient status. The relationship between dietary intake and disease has traditionally studied individual foods or nutrients but this approach does not allow examination of the synergistic or antagonistic effects of nutrients/foods, as they are consumed in the diet. This has led to a complementary approach to the study of diet and disease: dietary pattern analysis. This thesis aimed to explore the association between two dietary pattern (DP) approaches, 'a priori' and 'a posteriori', with chronic disease risk in two prospective studies (PRIME and Caerphilly). Secondly, it aimed to investigate associations between antioxidant micronutrient status and CVD Incidence and overall mortality risk in PRIME. Genetic variation may influence the absorption, metabolism and uptake of nutrients in the body. A final aim of this thesis was to examine if the status of vitamin C, retinol and carotenolds varied by genotype for a number of single-nuqleotide-polymorphisms (SNPs) In the PRIME study. Both a priori and a posteriori DP approaches supported the importance of broadly healthy dietary patterns and, importantly, dietary variety for health, particularly for mortality outcome~: Strong correlations between some micronutrients make it difficult to determine independent effects, however, mortality risk decreased linearly with increasing status of vitamin C, retinol, a-tocopherol and all carotenoids. CVD incidence was significantly inversely associated with retinol and (3-carotene status. Some evidence existed of an influence of genotype on AO micronutrient status for two out of the four examined SNPs. Phenotype is based on both genotype and environmental exposures and this thesis illustrates the value of examining both of these influencing factors, in a number of ways, In order to gain a better understanding of the complexities of the diet-disese relationship.

Observational and intervention evidence indicates that polyphenol-rich foods, in particular berries and dark chocolate, may influence cardiovascular disease risk. However, there are few polyphenol-specific dietary intervention studies. The aim of this thesis was to test the hypothesis that increasing overall polyphenol dietary intake, through increasing fruit and vegetable, berries, and dark chocolate intake, would improve microvascular function and other markers of cardiovascular risk. The primary endpoint was endothelium-dependent arterial vasodilator responses, assessed by venous occlusion plethysmography. Compliance was assessed using food diaries and biochemical markers of nutritional status. Other measures of cardiovascular risk included lipids, hsCRP, PAI-1, 11-dehydrothromboxane B2 and heart rate variability. A total of 99 volunteers completed the study. The intervention was well-tolerated and markers of compliance indicated good adherence to the diet. Between-group comparison of maximum % response to Ach was significantly improved in the high polyphenol group (p<0.001), with a trend towards a reduction in systolic blood pressure (p=0.059) and 11- dehydrothromboxane B2 (p=0.066), and a significant decrease in total cholesterol (p=0.042). There was no significant effect of the intervention on inflammatory markers and heart rate variability indices. Results were reanalysed with polyphenol-rich foods as a continuous variable. An extra portion of fruit and vegetables and dark chocolate was predicted to promote an absolute increase in the maximum response to acetylcholine of 14.0% and 112.5% respectively.

Cardiovascular complications are the leading cause of morbidity and mortality in the global epidemic of diabetes mellitus and despite current diabetic treatment strategies being effective for glycaemic control, the incidence of cardiovascular complications remains significant. Exceptionally, glucagon-like peptide-1 (GLP-1) targeted therapies, which are widely used in the treatment of hyperglycaemia, have been shown to elicit wide-ranging basal physiological cardiovascular effects, and more importantly, they may confer cardioprotective actions against acute myocardial infarction and chronic heart failure in both the presence and absence of hyperglycaemia/diabetes. However, few studies have investigated potential beneficial cardiac actions of GLP-1 targeted therapies in diabetes, due to the inherent difficulty of separating direct effects from those occurring secondary to established metabolic/glucose-lowering actions. Therefore, the aim of this thesis was to study the effects of GLP-1 mimetic, exendin-4, in experimental diabetic cardiomyopathy, with a specific focus on inflammation and the ECM. The findings of this thesis clearly demonstrate that exendin-4 attenuates experimental diabetic cardiac remodelling, at least in part, independently of its established glucose lowering actions, via reduction of myocardial macrophage infiltration and modulation of associated cytokines and chemokines. Specifically, the in vitro findings of this thesis provide strong evidence that the observed beneficial effects of exendin-4 in the diabetic heart may occur secondary to direct actions on infiltrating macrophages, which exert specific paracrine effects on ECM remodelling. These developments are clearly exciting and may have significant implications for the clinical management of both metabolic and cardiovascular diseases.

Late gadolinium enhancement (LGE) imaging is a widely used cardiovascular MRI technique. My work focused on developing new LGE MRI sequences to; identify plaque in the aortic vessel wall, to visualize areas of ventricular scar after myocardial infarction and pulmonary vein and atrial wall lesions after radiofrequency (RF) ablation for atrial fibrillation (AF). The double inversion recovery (DIR) sequence is traditionally used for vessel wall imaging. It however requires a Look Locker scan to choose the correct inversion time (TI) to achieve post-contrast blood suppression. The quadruple inversion recovery (QIR) sequence was later developed to suppress blood before and after contrast using identical imaging parameters. ECG-triggering was not required for the carotid arteries as there is adequate blood flow during the entire cardiac cycle to achieve sufficient blood exchange for blood suppression. I designed a new ECG-triggered QIR implementation for vessel wall imaging of the aorta which has variable flow during the cardiac cycle. I found it improved blood suppression, vessel wall sharpness and image quality scores compared to the un-triggered QIR implementation. The inversion recovery (IR) technique is the gold standard for imaging ventricular and atrial wall scar. It also requires a Look Locker scan to define the TI that suppresses normal myocardium in order to detect regions of scar. However, there is also often high IR blood signal that can hamper the detection of small sub-endocardial infarcts and scar size and transmurality measurements. I developed a novel dual-IR sequence that achieves suppression of normal myocardium and also reduces the blood signal. I found this improved blood suppression and inter-observer variability of scar size measurement and allowed imaging at an earlier time point compared to IR imaging for both ventricular and atrial wall scar. For ventricular scar, I also found improved expert confidence and inter-observer variability for transmurality assessment.