Siana Jones

University College London | UCL · Institute of Cardiovascular Sciences

Purpose of review: Continuous wave near infrared spectroscopy (CW NIRS) provides non-invasive technology to measure relative changes in oxy- and deoxy-haemoglobin in a dynamic environment. This allows determination of local skeletal muscle O2 saturation, muscle oxygen consumption ([Formula: see text]) and blood flow. This article provides a brief...

Background Exercise interventions are increasingly recognised to help reduce depressive symptoms; however, fatigue and perception of increased energy expenditure, which are often associated with depression, may be barriers to adherence. Although depression has been associated with a blunted cardiovascular stress response, little evidence exists des...

Aims/hypothesis The aim of this study was to compare exercise capacity, strength and skeletal muscle perfusion during exercise, and oxidative capacity between South Asians, African Caribbeans and Europeans, and determine what effect ethnic differences in the prevalence of type 2 diabetes has on these functional outcomes. Methods In total, 708 part...

Having the physical function to undertake activities of daily living (ADLs) is essential in order to maintain independence. The aim of this study is to investigate factors associated with physical function in older adults and determine if these associations differ in men versus women. In total, 726 participants (57% men; 73±7 years old) from a popu...

Background: An exaggerated blood pressure (BP) response to exercise and low exercise capacity are risk factors for cardiovascular disease (CVD). The effect of pharmacological antihypertensive treatment on exercise BP in older adults is largely unknown. This study investigates these effects accounting for differences in exercise capacity. Methods:...

3D-speckle tracking echocardiography(3D-STE) allows simultaneous assessment of ejection fraction(EF) and multidirectional strains, but its prognostic utility in the general population is unknown. We investigated if 3D-STE strains predicted a composite of major cardiac endpoints(MACE) beyond cardiovascular risk factors(CVDRF), and whether they were...

Background Three-dimensional echocardiography (3DE) measures of the left ventricle (LV) predict outcomes in high risk individuals, but their prognostic value in the general population is unknown. We aimed to establish whether 3DE was associated with mortality and morbidity in a multi-ethnic community-based sample, if associations differed by sex, a...

Measuring local haemodynamics in skeletal muscle has the potential to provide valuable insight into the oxygen delivery to tissue, especially during high demand situations such as exercise. The aim of this study was to compare the skeletal muscle microvascular response during post-occlusive reactive hyperaemia (PORH) with the response to exercise,...

There is an increasing body of evidence suggesting that vascular disease could contribute to cognitive decline and overt dementia. Of particular interest is atherosclerosis, as it is not only associated with dementia, but could be a potential mechanism through which cardiovascular disease directly impacts brain health. In this work, we evaluated th...

[This corrects the article DOI: 10.3389/fcvm.2020.591946.].

Background Both left ventricular (LV) ejection fraction (EF) and Global Longitudinal Strain (GLS) by 2D-echocardiography predict mortality and cardiac events, and GLS may be superior to EF. 3D-speckle tracking echocardiography (3D-STE), a recently validated method, allows simultaneous assessment of EF, GLS and principal tangential strain (PTS), but...

Purpose: To define and compare cardiovascular (CV) health scores (CHS) from adolescence (17 yrs) to emerging adulthood (24 yrs) using longitudinal data from a large British birth cohort. Methods: 3142 participants from the Avon Longitudinal Study of Parents and Children (ALSPAC) study attended clinical investigations at 17.8 ± 0.4 yrs and 24.0 ± 0....

Background: People of South Asian and African Caribbean ethnicities living in UK have a high risk of cardiometabolic disease. Limited data exist regarding detailed cardiometabolic phenotyping in this population. Methods enabling this are widely available, but the practical aspects of undertaking such studies in large and diverse samples are seldom...

The commonest causes of dementia are Alzheimer's disease and vascular cognitive impairment. Although these conditions have been viewed as distinct entities, there is increasing evidence that neurodegenerative and vascular pathologies interact or overlap to cause cognitive decline, and that at least in some cases individuals at risk of cognitive dec...

Background: People of South Asian and African Caribbean ethnicities living in UK have a high risk of cardiometabolic disease. Limited data exist regarding detailed cardiometabolic phenotyping in this population. Methods enabling this are widely available, but the practical aspects of undertaking such studies in large and diverse samples are seldom...

This chapter was inadvertently published as an open access chapter. However, the open access for this chapter has now been reverted.

Aims: Remodelling of the cardiovascular system (including heart and vasculature) is a dynamic process influenced by multiple physiological and pathological factors. We sought to understand whether remodelling in response to a stimulus, exercise training, altered with healthy ageing. Methods: A total of 237 untrained healthy male and female subjects...

Background Marathon running in novices represents a natural experiment of short-term cardiovascular remodeling in response to running training. We examine whether this stimulus can produce exercise-induced left ventricular (LV) trabeculation. Methods Sixty-eight novice marathon runners aged 29.5 ± 3.2 years had indices of LV trabeculation measured...

AimsMarathon running is a popular ambition in modern societies inclusive of non-athletes. Previous studies have highlighted concerning transient myocardial dysfunction and biomarker release immediately after the race. Whether this method of increasing physical activity is beneficial or harmful remains a matter of debate. We examine in detail the re...

Introduction: In adults, aging is associated with a rise in blood pressure (BP) and a disproportionate increase in central systolic blood pressure (cSBP) relative to brachial SBP (bSBP) (i.e. reduced aortic to radial pulse pressure amplification (PPamp)). But changes in brachial and central BP have not been studied in the transition from adolescenc...

Background: Participation in structured exercise training may improve microvascular function. Post occlusive reactive hyperaemia (PORH) is a measure of microvascular function in skeletal muscle and can be assessed using near-infrared spectroscopy (NIRS). We examined PORH following a short and a long arterial occlusion to test whether individuals wh...

Introduction: Adult obesity is associated with greater arterial stiffness however in youth the relationship is unclear. We investigated associations between arterial stiffness and adiposity and explored the contribution of blood pressure from adolescence to emerging adulthood (17–24 yrs). Methods: 3885 individuals (2152 female) had measurements of...

Background: Functional capacity declines with age leading to disability and increased cost of health and social care. In older adults, factors that influence the ability to sustain sub-maximal exercise (a marker of functional capacity) are not well defined. We aimed to determine the contribution of cardiac function, skeletal muscle oxygen desaturat...

Background: Aging increases aortic stiffness, contributing to cardiovascular risk even in healthy individuals. Aortic stiffness is reduced through supervised training programs, but these are not easily generalizable. Objectives: The purpose of this study was to determine whether real-world exercise training for a first-time marathon can reverse...

Skeletal muscle metabolic function is known to respond positively to endurance exercise interventions, such as marathon training. Studies investigating skeletal muscle have typically used muscle biopsy samples or magnetic resonance spectroscopy (MRS) to interrogate metabolic function. We aimed to non-invasively detect exercise-training-induced impr...

Skeletal muscle metabolic function is known to respond positively to endurance exercise interventions, such as marathon training. Studies investigating skeletal muscle have typically used muscle biopsy samples or magnetic resonance spectroscopy (MRS) to interrogate metabolic function. We aimed to non-invasively detect exercise-training-induced impr...

Introduction Body mass index (BMI) is independently associated with increased left ventricle mass (LVM) and remodeling in children. However associations from adolescence to emerging adulthood are unknown. Purpose To investigate associations between the change (Δ) in BMI to Δ in cardiac structure from 17 to 25 yrs using a large population-based sam...

Background: Wave intensity analysis (WIA) in the aorta offers important clinical and mechanistic insight into ventriculo-arterial coupling, but is difficult to measure non-invasively. We performed WIA by combining standard cardiovascular magnetic resonance (CMR) flow-velocity and non-invasive central blood pressure (cBP) waveforms. Methods and re...

PURPOSE: This case-report characterised the respiratory, cardiovascular, and nutritional/gastrointestinal (GI) responses of a trained individual to a novel ultra-endurance exercise challenge. METHODS: A male athlete (age 45 y, mass 80.7 kg, stature 1.71 m, V̇O2max 54.8 mL∙kg-1∙min-1) summited 100 mountains on foot (all elevations >600 m) in 25 con...

Background: This case-report characterized the respiratory, cardiovascular, and nutritional/gastrointestinal (GI) responses of a trained individual to a novel ultra-endurance exercise challenge. Case Presentation: A male athlete (age 45 years; V ˙ O2max 54.0 mL⋅kg-1⋅min-1) summited 100 mountains on foot in 25 consecutive days (all elevations >60...

Background Ageing is strongly associated with aortic stiffening, contributing to increased cardiovascular risk even in healthy individuals. Aortic stiffness is reduced in lifelong athletes, but whether training in novice runners can modify this process remains unclear. We hypothesized that exercise training for a first-time marathon would have bene...

Background: Physical activity interventions are increasingly recognised to help reduce depressive symptoms; however, fatigue and perception of increased energy expenditure, often associated with depression, may be barriers to compliance. Whether this association differs between different ethnicities is unknown. This analysis investigates associatio...

Cardiovascular structure by sex.

Pre-exercise and delta systolic BP and cardiovascular structure (sex-pooled analyses).

Unlike in older people, it has been suggested that elevated blood pressure (BP) in young people is because of high cardiac output accompanied by normal total peripheral resistance (TPR)-a hyperkinetic/hyperdynamic circulation. We investigated this in a large, United Kingdom-based birth cohort of adolescents. The study was conducted on 2091 17-year-...

Purpose Dynamic exercise results in increased systolic blood pressure (BP). Irrespective of resting BP, some individuals may experience exaggerated rise in systolic BP with exercise, which in adulthood is associated with risk of hypertension, and cardiovascular (CV) disease. It is unknown if exercise BP is associated with markers of CV structure du...

It is uncommon for cardio-respiratory fitness and skeletal muscle metabolic function to be assessed independently within an exercise test. Exercise capacity may require adaptation of one or other of these systems to a greater or lesser extent and the presence of disease may affect them to different extents. The physiological mechanisms underpinning...

Introduction Exercise training has beneficial effects on blood pressure (BP), however the physiological mechanisms remain unclear, and the impact on regional aortic haemodynamics is unexplored. We studied the effects of exercise training on central BP (cBP) and regional aortic stiffness using cardiovascular magnetic resonance (CMR). Methods Untrai...

Skeletal muscle metabolic function is known to respond positively to exercise interventions. Developing non-invasive techniques that quantify metabolic adaptations and identifying interventions that impart successful response are ongoing challenges for research. Healthy non-athletic adults (18-35 years old) were enrolled in a study investigating ph...

It is often necessary to assess physical function in older adults to monitor disease progression, rehabilitation or decline in function with age. However, increasing frailty and poor balance that accompany aging are common barriers to exercise testing protocols. We investigated whether a 6-min stepper test (6MST) was acceptable to older adults and...

Aims Cardiac resynchronization therapy (CRT) may exert its beneficial haemodynamic effect by improving ventricular synchrony and improving atrioventricular (AV) timing. The aim of this study was to establish the relative importance of the mechanisms through which CRT improves cardiac function and explore the potential for additional improvements wi...

Introduction: Wave intensity analysis (WIA) has found particular applicability in the coronary circulation where it can quantify travelling waves that accelerate and decelerate blood flow. The most important wave for the regulation of flow is the backward-travelling decompression wave (BDW). Coronary WIA has hitherto always been calculated from in...

Objectives: Ethnic minority groups in the UK experience marked differences in cardiovascular disease risk. We investigated differences in arterial central haemodynamics, stiffness, and load in a tri-ethnic population-based cohort. Methods: A total of 1312 participants (70 ± 6 years) underwent echocardiography and measurement of brachial and cent...

In this study, we designed and tested a new algorithm, which we call the 'restricted parabola', to identify the optimum atrioventricular (AV) delay in patients with biventricular pacemakers. This algorithm automatically restricts the hemodynamic data used for curve fitting to the parabolic zone in order to avoid inadvertently selecting an AV optimu...

Whether adjusting interventricular (VV) delay changes haemodynamic efficacy of cardiac resynchronization therapy (CRT) is controversial, with conflicting results. This study addresses whether the convention for keeping atrioventricular (AV) delay constant during VV optimization might explain these conflicts. Twenty-two patients in sinus rhythm with...

Background: Manufacturers have each implemented manufacturer specific methods for electrogram based optimization of AV delay in CRT devices. Agreement between manufacturer algorithms has never been formally tested. Where the algorithms are fully published and available, we tested agreement between different device based AV optimisation scheme, and...

Background The term “resynchronisation” indicates restoration of simultaneity, which by implication refers to ventricular timings (VV delay) rather than atrioventricular (AV) delay. However, while AV delay adjustment causes large haemodynamic effects, different laboratories have reported contradictory results concerning the strength of the effect o...

In clinical practice, echocardiographers are often unkeen to make the significant time investment to make additional multiple measurements of Doppler velocity. Main hurdle to obtaining multiple measurements is the time required to manually trace a series of Doppler traces. To make it easier to analyze more beats, we present the description of an ap...

To investigate whether discrepancies in trials of use of bone marrow stem cells in patients with heart disease account for the variation in reported effect size in improvement of left ventricular function. Identification and counting of factual discrepancies in trial reports, and sample size weighted regression against therapeutic effect size. Meta...

Echocardiographic optimization of pacemaker settings is the current standard of care for patients treated with cardiac resynchronization therapy. However, the process requires considerable time of expert staff. The BRAVO study is a non-inferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular (VV) dela...

Objective Diabetes is associated with left ventricular diastolic and systolic dysfunction. South Asians may be at particular risk of developing LV dysfunction due to a high prevalence of diabetes. We investigated the role of diabetes and hyperglycaemia in LV dysfunction in a community-based cohort of older South Asians and White Europeans.Research...

AimsFull-disclosure study describing Doppler patterns during iterative atrioventricular delay (AVD) optimization of biventricular pacemakers (cardiac resynchronization therapy, CRT).Method and resultsDoppler traces of the first 50 eligible patients undergoing iterative Doppler AVD optimization in the BRAVO trial were examined. Three experienced obs...

Changes in ventricular rotation measured by two-dimensional speckle tracking echocardiography (2DSTE) are early indicators of cardiac disease. Data on the clinical feasibility of this important measure are scarce and there is no information on the comparability of different software versions. We assessed the feasibility, reproducibility and within...

Background: In adults central blood pressure has stronger associations with cardiovascular outcomes than peripheral blood pressure, with some evidence that this difference is greater in mid- than older-aged adults. The relationship of central blood pressure to cardiovascular structure and function in adolescence is unclear. Aim: To compare associat...