Characterizing the influence of cardiorespiratory fitness on left atrial size and function in the general population

Increased left atrial (LA) size and reduced LA function have been associated with heart failure and atrial fibrillation (AF) in at-risk populations. However, atrial remodeling has also been associated with exercise training and the relationship between fitness, LA size, and function has not been defined across the fitness spectrum. In a cross-sectional study of 559 ostensibly healthy participants, comprising 304 males (mean age, 46 ± 20 yr) and 255 females (mean age, 47 ± 15 yr), we sought to define the relationship between cardiorespiratory fitness (CRF), LA size, and function. We also aimed to interrogate sex differences in atrial factors influencing CRF. Echocardiographic measures included biplane measures of LA volumes indexed to body surface area (LAVi) and atrial deformation using two-dimensional speckle tracking. CRF was measured as peak oxygen consumption (V̇o2peak) during cardiopulmonary exercise testing (CPET). Using multivariable regression, age, sex, weight, and LAVi (P < 0.001 for all) predicted V̇o2peak (P < 0.001, R2 = 0.66 for combined model). After accounting for these variables, heart rate reserve added strength to the model (P < 0.001, R2 = 0.74) but LA strain parameters did not predict V̇o2peak. These findings add important nuance to the perception that LA size is a marker of cardiac pathology. LA size should be considered in the context of fitness, and it is likely that the adverse prognostic associations of increased LA size may be confined to those with LA enlargement and low fitness.NEW & NOTEWORTHY Left atrial (LA) structure better predicts cardiorespiratory fitness (CRF) than LA function. LA function adds little statistical value to predictive models of peak oxygen uptake (V̇o2peak) in healthy individuals, suggesting limited discriminatory for CRF once LA size is factored. In the wider population of ostensibly healthy individuals, the association between increased LA volume and higher CRF provides an important counter to the association between atrial enlargement and heart failure symptoms in those with cardiac pathology.

Use of Clinical and Echocardiographic Evaluation to Assess the Risk of Heart Failure

BACKGROUND

Clinical and echocardiographic features predict incident heart failure (HF), but the optimal strategy for combining them is unclear.

OBJECTIVES

This study sought to define an effective means of using echocardiography in HF risk evaluation.

METHODS

The same clinical and echocardiographic evaluation was obtained in 2 groups with HF risk factors: a training group (n = 926, followed to 7 years) and a validation group (n = 355, followed to 10 years). Clinical risk was categorized as low, intermediate, and high using 4-year ARIC (Atherosclerosis Risk In Communities) HF risk score cutpoints of 9% and 33%. A risk stratification algorithm based on clinical risk and echocardiographic markers of stage B HF (SBHF) (abnormal global longitudinal strain [GLS], diastolic dysfunction, or left ventricular hypertrophy) was developed using a classification and regression tree analysis and was validated.

RESULTS

HF developed in 12% of the training group, including 9%, 18%, and 73% of low-, intermediate-, and high-risk patients. HF occurred in 8.6% of stage A HF and 19.4% of SBHF (P < 0.001), but stage A HF with clinical risk of ≥9% had similar outcome to SBHF. Abnormal GLS (HR: 2.92 [95% CI: 1.95-4.37]; P < 0.001) was the strongest independent predictor of HF. Normal GLS and diastolic function reclassified 61% of the intermediate-risk group into the low-risk group (HF incidence: 12%). In the validation group, 11% developed HF over 4.5 years; 4%, 17%, and 39% of low-, intermediate-, and high-risk groups. Similar results were obtained after exclusion of patients with known coronary artery disease. The echocardiographic parameters also provided significant incremental value to the ARIC score in predicting new HF admission (C-statistic: 0.78 [95% CI: 0.71-0.84] vs 0.83 [95% CI: 0.77-0.88]; P = 0.027).

CONCLUSIONS

Clinical risk assessment is adequate to classify low and high HF risk. Echocardiographic evaluation reclassifies 61% of intermediate-risk patients.

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Associations between symptoms and functional capacity in patients after COVID-19 infection and community controls

BACKGROUND

Post-acute sequelae of COVID-19 (PASC or 'long COVID') reflect ongoing symptoms, but these are non-specific and common in the wider community. Few reports of PASC have been compared with a control group.

AIMS

To compare symptoms and objective impairment of functional capacity in patients with previous COVID-19 infection with uninfected community controls.

METHODS

In this community-based, cross-sectional study of functional capacity, 562 patients from Western Melbourne who had recovered from COVID-19 infections in 2021 and 2022 were compared with controls from the same community and tested for functional capacity pre-COVID-19. Functional impairment (<85% of the predicted response) was assessed using the Duke Activity Status Index (DASI) and 6-min walk distance (6MWD) test. A subgroup underwent cardiopulmonary exercise testing before and after exercise training.

RESULTS

Of 562 respondents (age 54 ± 12 years, 69% women), 389 were symptomatic. Functional impairment (<85% predicted metabolic equivalent of tasks) was documented by DASI in 149 participants (27%), and abnormal 6MWD (<85% predicted) was observed in 14% of the symptomatic participants. Despite fewer risk factors and younger age, patients with COVID-19 had lower functional capacity by 6MWD (P < 0.001) and more depression (P < 0.001) than controls. In a pilot group of seven participants (age 58 ± 12 years, two women, VO2 18.9 ± 5.7 mL/kg/min), repeat testing after exercise training showed a 20% increase in peak workload.

CONCLUSIONS

Although most participants (69%) had symptoms consistent with long COVID, significant subjective functional impairment was documented in 27% and objective functional impairment in 14%. An exercise training programme might be beneficial for appropriately selected patients.

Too Little of a Good Thing: Strong Associations Between Cardiac Size and Fitness Among Women

BACKGROUND

Cardiorespiratory fitness (CRF) is associated with functional impairment and cardiac events, particularly heart failure (HF). However, the factors predisposing women to low CRF and HF remain unclear.

OBJECTIVES

This study sought to evaluate the association between CRF and measures of ventricular size and function and to examine the potential mechanism linking these factors.

METHODS

A total of 185 healthy women aged >30 years (51 ± 9 years) underwent assessment of CRF (peak volume of oxygen uptake [Vo2peak]) and biventricular volumes at rest and during exercise by using cardiac magnetic resonance (CMR). The relationships among Vo2peak, cardiac volumes, and echocardiographic measures of systolic and diastolic function were assessed using linear regression. The effect of cardiac size on cardiac reserve (change in cardiac function during exercise) was assessed by comparing quartiles of resting left ventricular end-diastolic volume (LVEDV).

RESULTS

Vo2peak was strongly associated with resting measures of LVEDV and right ventricular end-diastolic volume (R2 = 0.58-0.63; P < 0.0001), but weakly associated with measures of resting left ventricular (LV) systolic and diastolic function (R2 = 0.01-0.06; P < 0.05). Increasing LVEDV quartiles were positively associated with cardiac reserve, with the smallest quartile showing the smallest reduction in LV end-systolic volume (quartile [Q]1: -4 mL vs Q4: -12 mL), smallest augmentation in LV stroke volume (Q1: +11 mL vs Q4: +20 mL) and cardiac output (Q1: +6.6 L/min vs Q4: +10.3 L/min) during exercise (interaction P < 0.001 for all).

CONCLUSIONS

A small ventricle is strongly associated with low CRF because of the combined effect of a smaller resting stroke volume and an attenuated capacity to increase with exercise. The prognostic implications of low CRF in midlife highlight the need for further longitudinal studies to determine whether women with small ventricles are predisposed to functional impairment, exertional intolerance, and HF later in life.

Measurement of Stroke Volume With Echocardiography Compared to Gold Standard Cardiac Magnetic Resonance Imaging: An Observational Study

OBJECTIVES

The authors aimed to compare the assessment of left ventricular (LV) stroke volume with transthoracic echocardiography (TTE) using 2- and 3-dimensional (2D and 3D) Doppler and volumetric techniques with gold standard cardiac magnetic resonance imaging (CMR).

DESIGN

An observational study.

SETTING

A medical research institute.

PARTICIPANTS

A total of 187 volunteer participants free of known structural heart disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

LV stroke volume was measured with TTE using the following 4 techniques: LV outflow tract (LVOT) pulsed wave Doppler with 2D LVOT area, LVOT pulsed wave Doppler with 3D LVOT area, 2D volumetric (Simpson's biplane), and 3D volumetric techniques. This was compared with gold standard CMR. Stroke volume measured with echocardiography underestimated stroke volume compared to CMR by all techniques (p < 0.001 for all values compared to CMR). The LVOT Doppler stroke volume with a 3D area most closely agreed with CMR, with a bias of 6.35%. This bias progressively increased with 3D volumetric (13.4%), LVOT Doppler with a 2D area (15.1%), and 2D volumetric (18.3%) stroke volume techniques, with wider limits of agreement.

CONCLUSION

Of the 4 echocardiographic LV stroke volume measurement methods the authors assessed, stroke volume with LVOT Doppler using 3D measurement of LVOT area most closely approximates gold standard CMR.

A membrane-free microfluidic approach to mucus permeation for efficient differentiation of mucoadhesive and mucopermeating nanoparticulate systems

The gastrointestinal mucus barrier is a widely overlooked yet essential component of the intestinal epithelium, responsible for the body's protection against harmful pathogens and particulates. This, coupled with the increasing utilisation of biological molecules as therapeutics (e.g. monoclonal antibodies, RNA vaccines and synthetic proteins) and nanoparticle formulations for drug delivery, necessitates that we consider the additional absorption barrier that the mucus layer may pose. It is imperative that in vitro permeability methods can accurately model this barrier in addition to standardised cellular testing. In this study, a mucus-on-a-chip (MOAC) microfluidic device was engineered and developed to quantify the permeation kinetics of nanoparticles through a biorelevant synthetic mucus layer. Three equivalently sized nanoparticle systems, formulated from chitosan (CSNP), mesoporous silica (MSNP) and poly (lactic-co-glycolic) acid (PLGA-NP) were prepared to encompass various surface chemistries and nanostructures and were assessed for their mucopermeation within the MOAC. Utilising this device, the mucoadhesive behaviour of chitosan nanoparticles was clearly visualised, a phenomenon not often observed via standard permeation models. In contrast, MSNP and PLGA-NP displayed mucopermeation, with significant differences in permeation pattern due to specific mucus-nanoparticle binding. Further optimisation of the MOAC to include a more biorelevant mucus mimic resulted in 5.5-fold hindered PLGA-NP permeation compared to a mucin solution. Furthermore, tracking of PLGA-NP at a single nanoparticle resolution revealed rank-order correlations between particle diffusivity and MOAC permeation. This device, including utilisation of biosimilar mucus, provides a unique ability to quantify both mucoadhesion and mucopenetration of nano-formulations and elucidate mucus binding interactions on a microscopic scale.

Echocardiographic detection of heart valve disease in a community cohort of asymptomatic Australians > 65 years with cardiovascular risk factors

BACKGROUND

Valvular heart disease is becoming an increasingly prevalent with population ageing. We sought to define the current prevalence of valvular heart disease in Australia.

METHODS

The TasELF and VicELF studies prospectively recruited 962 asymptomatic participants ≥65 years, with at least one cardiovascular risk factor, from the Tasmanian and Victorian communities. People were excluded if they had a previous diagnosis of heart failure, or a life expectancy <1 year. All underwent baseline echocardiography. Those with moderate or severe valvular disease were identified. The current prevalence of clinically significant valve disease was applied to the Australian Bureau of Statistics population projections.

RESULTS

Echocardiograms were interpretable in 943 participants (98%). Clinically significant valve disease was present in 5% of the population, and mitral regurgitation was the most common overall valvular lesion, present in 36% of the population. The projected numbers of people with clinically significant valvular disease is expected to increase significantly across all age groups by the year 2060.

CONCLUSIONS

Clinically significant yet asymptomatic valvular disease was prevalent in a large community cohort of participants with at least one risk factor. The total burden of valvular heart disease is expected to increase dramatically over the coming decades.

Exercise for the Prevention of Anthracycline-Induced Functional Disability and Cardiac Dysfunction: The BREXIT Study

BACKGROUND

Breast cancer survivors treated with anthracycline-based chemotherapy (AC) have increased risk of functional limitation and cardiac dysfunction. We conducted a 12-month randomized controlled trial in 104 patients with early-stage breast cancer scheduled for AC to determine whether 12 months of exercise training (ExT) could attenuate functional disability (primary end point), improve cardiorespiratory fitness (VO₂peak), and prevent cardiac dysfunction.

METHODS

Women 40 to 75 years of age with stage I to III breast cancer scheduled for AC were randomized to 3 to 4 days per week aerobic and resistance ExT for 12 months (n=52) or usual care (UC; n=52). Functional measures were performed at baseline, at 4 weeks after AC (4 months), and at 12 months, comprising: (1) cardiopulmonary exercise testing to quantify VO₂peak and functional disability (VO₂peak ≤18.0 mL·kg^-1·min^-1); (2) cardiac reserve (response from rest to peak exercise), quantified with exercise cardiac magnetic resonance measures to determine changes in left and right ventricular ejection fraction, cardiac output, and stroke volume; (3) standard-of-care echocardiography-derived resting left ventricular ejection fraction and global longitudinal strain; and (4) biochemistry (troponin and BNP [B-type natriuretic peptide]).

RESULTS

Among 104 participants randomized, greater study attrition was observed among UC participants (P=0.031), with 93 women assessed at 4 months (ExT, n=49; UC, n=44) and 87 women assessed at 12 months (ExT, n=49; UC, n=38). ExT attenuated functional disability at 4 months (odds ratio, 0.32 [95% CI, 0.11-0.94]; P=0.03) but not at 12 months (odds ratio, 0.27 [95% CI, 0.06-1.12]; P=0.07). In a per-protocol analysis, functional disability was prevented entirely at 12 months among participants adherent to ExT (ExT, 0% versus UC, 20%; P=0.005). Compared with UC at 12 months, ExT was associated with a net 3.5-mL·kg^-1·min^-1 improvement in VO₂peak that coincided with greater cardiac output, stroke volume, and left and right ventricular ejection fraction reserve (P<0.001 for all). There was no effect of ExT on resting measures of left ventricular function. Postchemotherapy troponin increased less in ExT than in UC (8-fold versus 16-fold increase; P=0.002). There were no changes in BNP in either group.

CONCLUSIONS

In women with early-stage breast cancer undergoing AC, 12 months of ExT did not attenuate functional disability, but provided large, clinically meaningful benefits on VO₂peak and cardiac reserve.

REGISTRATION

URL: https://www.anzctr.org.au/; Unique identifier: ACTRN12617001408370.

Current Applications of Robot-Assisted Ultrasound Examination

Despite advances in miniaturization and automation, the need for expert acquisition of a full echocardiogram, including Doppler, has restricted access in remote areas. Recent developments in robotics, teleoperation, and upgraded telecommunications infrastructure may provide a solution to this deficiency. Robot-assisted teleoperated ultrasound examination can aid medical diagnosis in remote locations and may improve health inequalities between rural and urban settings. This review aimed to analyze the status of teleoperated robotic systems for ultrasound examinations, evaluate clinical and preclinical applications, identify limitations, and outline future directions for clinical use. Overall, robot-assisted teleoperated ultrasound is feasible and safe in the reported clinical and preclinical studies, with the robots able to follow the hand movements performed by sonographers and researchers from a distance or in local networks. Moreover, multiple types of ultrasound examinations have been performed in remote areas, with a high success rate nearly comparable to that of conventional sonography. The studies showed that although a low-bandwidth link can be used to control a robot, the bandwidth requirements for real-time transmission of video and ultrasound images are significantly higher. Furthermore, if haptic feedback is implemented, the bandwidth requirements are increased. Haptically enabled systems that improve robotic control are necessary for accelerating the introduction to clinical use. Haptic feedback and enhanced front-end interface control for remote users are vital aspects required for clinical application. The incorporation of artificial intelligence through either aiding in window acquisition (knowledge of anatomical landmarks to adjust scanning planes) or through measurement and disease identification is yet to be researched. However, it has the potential to lead to dramatic advances. A new generation of robots is in development, and several projects in the preclinical stage reveal a promising future to overcome the shortage of health professionals in remote areas.

Three-dimensional echocardiography of the athlete's heart: a comparison with cardiac magnetic resonance imaging

Three-dimensional echocardiography (3DE) is the most accurate cardiac ultrasound technique to assess cardiac structure. 3DE has shown close correlation with cardiac magnetic resonance imaging (CMR) in various populations. There is limited data on the accuracy of 3DE in athletes and its value in detecting alterations during follow-up. Indexed left and right ventricular end-diastolic volume (LVEDVi, RVEDVi), end-systolic volume, ejection fraction (LVEF, RVEF) and left ventricular mass (LVMi) were assessed by 3DE and CMR in two-hundred and one competitive endurance athletes (79% male) from the Pro@Heart trial. Sixty-four athletes were assessed at 2 year follow-up. Linear regression and Bland-Altman analyses compared 3DE and CMR at baseline and follow-up. Interquartile analysis evaluated the agreement as cardiac volumes and mass increase. 3DE showed strong correlation with CMR (LVEDVi r = 0.91, LVEF r = 0.85, LVMi r = 0.84, RVEDVi r = 0.84, RVEF r = 0.86 p < 0.001). At follow up, the percentage change by 3DE and CMR were similar (∆LVEDVi r = 0.96 bias - 0.3%, ∆LVEF r = 0.94, bias 0.7%, ∆LVMi r = 0.94 bias 0.8%, ∆RVESVi r = 0.93, bias 1.2%, ∆RVEF r = 0.87 bias 0.4%). 3DE underestimated volumes (LVEDVi bias - 18.5 mL/m², RVEDVi bias - 25.5 mL/m²) and the degree of underestimation increased with larger dimensions (Q1vsQ4 LVEDVi relative bias - 14.5 versus - 17.4%, p = 0.016; Q1vsQ4 RVEDVi relative bias - 17 versus - 21.9%, p = 0.005). Measurements of cardiac volumes, mass and function by 3DE correlate well with CMR and 3DE accurately detects changes over time. 3DE underestimates volumes and the relative bias increases with larger cardiac size.

Association of biomarkers and risk scores with subclinical left ventricular dysfunction in patients with type 2 diabetes mellitus

BACKGROUND

Subclinical LV dysfunction (LVD) identifies heart failure (HF) risk in type 2 diabetes mellitus (T2DM). We sought the extent to which clinical scores (ARIC-HF, WATCH-DM), natriuretic peptides (NTpBNP) and troponin (hs-TnT) were associated with subclinical LV dysfunction (LVD). These associations could inform the ability of these tests to identify which patients should undergo echocardiography.

METHODS

Participants with T2DM were prospectively recruited from three community-based populations. ARIC-HF risk at 4 years and WATCH-DM scores were calculated from clinical data. NTpBNP and hs-TnT were measured using an electro-chemiluminescence assay. All underwent a comprehensive echocardiogram. We calculated the sensitivity and specificity of clinical scores and biomarkers to identify abnormal global longitudinal strain (GLS ≥ -16%)), diastolic function (E/e' ≥ 14 or e' < 8 cm/s), left atrial volume index (LAV > 34 ml/m²) and LV hypertrophy (LV mass index > 88 g/m² (F) > 102 g/m²(M)).

RESULTS

Of 804 participants (median age 69 years [inter-quartile range (IQR) 65-73], 36% female), clinical scores suggested significant HF risk (median ARIC-HF 8% [IQR 4-12]; WATCH-DM 10 points [IQR 8-12]), and the median NTpBNP was 50 pg/mL [IQR 25-101] and hs-TnT 9.6 pg/mL [IQR 6.8-13.6]. Abnormal GLS was present in 126 (17%), elevated E/e' in 114 (15%), impaired e' in 629 (78%), increased LAV in 351 (44%) and LV hypertrophy in 113 (14%). After adjustments for age, body-mass index, and renal function, each standard deviation increase in NTpBNP was associated with a GLS increase of 0.32 (p < 0.001) and hs-TnT increase by 0.26 (p < 0.001). Similar trends were observed with ARIC-HF (standardised β = 0.22, p < 0.001) and WATCH-DM (standardised β = 0.22, p < 0.001) in univariable analyses. However, none of the risk assessment tools provided satisfactory discrimination for abnormal GLS (AUC 63%), diastolic indices (e' AUC 54-61%) or LV mass (AUC 59-67%). At a sensitivity of 90%, there was an unacceptably low (< 50%) specificity.

CONCLUSION

Although risk assessment based on clinical scores or biomarkers would be desirable to stratify HF risk in people with T2DM, they show a weak relationship with subclinical LVD.

Optimisation of a High-Throughput Model for Mucus Permeation and Nanoparticle Discrimination Using Biosimilar Mucus

High-throughput permeation models are essential in drug development for timely screening of new drug and formulation candidates. Nevertheless, many current permeability assays fail to account for the presence of the gastrointestinal mucus layer. In this study, an optimised high-throughput mucus permeation model was developed employing a highly biorelevant mucus mimic. While mucus permeation is primarily conducted in a simple mucin solution, the complex chemistry, nanostructure and rheology of mucus is more accurately modelled by a synthetic biosimilar mucus (BSM) employing additional protein, lipid and rheology-modifying polymer components. Utilising BSM, equivalent permeation of various molecular weight fluorescein isothiocyanate-dextrans were observed, compared with native porcine jejunal mucus, confirming replication of the natural mucus permeation barrier. Furthermore, utilising synthetic BSM facilitated the analysis of free protein permeation which could not be quantified in native mucus due to concurrent proteolytic degradation. Additionally, BSM could differentiate between the permeation of poly (lactic-co-glycolic) acid nanoparticles (PLGA-NP) with varying surface chemistries (cationic, anionic and PEGylated), PEG coating density and size, which could not be achieved by a 5% mucin solution. This work confirms the importance of utilising highly biorelevant mucus mimics in permeation studies, and further development will provide an optimal method for high-throughput mucus permeation analysis.

Patellar ligament desmopathy in the horse – a review and comparison to human patellar tendinopathy (‘Jumper’s knee’)

Patellar ligament desmopathy in horses is regarded as an uncommon condition with unclear aetiology. Of the three patellar ligaments in the horse, the intermediate is the one most often diagnosed with desmopathy in horses presenting with chronic lameness. This structure corresponds to the patellar tendon in humans. As diagnostic imaging modalities continuously improve, changes in echogenicity of the patellar ligaments are identified ultrasonographically with increasing frequency. However, disruption of the normal fibre pattern may be present also in patellar ligaments in horses that show no signs of lameness. Similarly, there is a poor correlation between pain and diagnostic imaging findings in human patellar tendinopathy. Consequently, there appears to be a knowledge gap pertaining to normal ultrasonographic variation and diagnostic criteria for disease of the patellar ligaments in horses. Furthermore, local anaesthetic techniques to verify the diagnosis are poorly described, and due to the low number of treated cases, no specific treatment modality can be recommended on a scientific basis. The aim of this paper is to review the current knowledge regarding the pathogenesis, diagnosis and management of patellar ligament desmopathy in horses, compare this condition with patellar tendinopathy in humans, and identify areas for further research to increase the diagnostic accuracy in horses. We conclude that there is a profound need for better descriptions of ultrasonographic variation and pathological changes of the equine patellar ligaments. Identification of areas of maximal ligament strain and descriptions of early histopathological changes could render more information on the possible aetiology, preventive measurements and treatment options of desmopathy. Description of regional innervation could aid in development of methods for diagnostic anaesthesia to verify pain originating from the ligaments.

Nurse-Provided Lung and Inferior Vena Cava Assessment in Patients With Heart Failure

BACKGROUND

Residual congestion detected using handheld ultrasound may be associated with increased risk of readmission and death after hospitalization for acute decompensated heart failure (ADHF). However, effective application necessitates routine use by nonexperts delivering clinical care.

OBJECTIVES

The objective of this study was to determine the ability of heart failure (HF) nurses to deliver a predischarge lung and inferior vena cava (IVC) assessment (LUICA) to predict 90-day outcomes.

METHODS

In this multisite, prospective, observational study, HF nurses scanned 240 patients with ADHF (median age: 77 years; 56% men) using a 9-zone LUICA protocol. Obtained images were reviewed by independent nurses who were blinded to clinical characteristics and outcomes. Based on a B-line cut-off of 10, patients were dichotomized as congested (n = 115) or not congested (n = 125).

RESULTS

Congested patients were more likely to have previous cardiac operations, long-standing HF (>6 months), and renal impairment. At 90 days, HF readmission or mortality occurred in 42 congested patients (37%) compared with 18 noncongested patients (14%). Pulmonary congestion increased at 30-day (OR: 3.86; 95% CI: 1.65-8.99; P < 0.01) and 90-day (OR: 3.42; 95% CI: 1.82-6.4; P < 0.01) HF readmission or mortality risk and 90-day mortality (OR: 5.18; 95% CI: 1.44-18.69; P < 0.01). Pulmonary congestion increased the 90-day odds of HF readmission and/or death by 3.3- to 4.2-fold (P < 0.01), independent of demographics, HF characteristics, comorbidities, and event risk score. Over 90 days, days alive out of hospital were fewer (78.3 ± 21.4 days vs 85.5 ± 12.4 days; P < 0.01) in congested patients.

CONCLUSIONS

LUICA can be a powerful tool for detection of predischarge residual congestion. HF nurses can obtain images and provide diagnostic reports that are predictive of ADHF outcomes.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Diastolic flow in the left ventricular outflow tract - A normal physiological and underappreciated echocardiographic finding

PURPOSE

Diastolic waveforms in the left ventricular outflow tract (LVOT) are commonly observed with Doppler echocardiography. The incidence and mechanism are not well described.

METHODS

This was a retrospective observational study of 186 adult patients, athletes and non-athletes, free of known cardiac disease, presenting for comprehensive transthoracic echocardiography at a research institute. We aimed to evaluate the incidence and echocardiographic associations between LVOT diastolic waveforms.

RESULTS

Left ventricular outflow tract early to mid-diastolic waveforms were present in 100% of athletes and 95% of non-athletes. The LVOT diastolic velocity time integral was larger in athletes than non-athletes with a mean 8.3 cm (95% CI (7.6-8.9)) vs. 5.1 cm (4.4-5.9) (P < 0.0001). Multivariate predictors of this diastolic waveform were age (P = 0.002), slower heart rate (P = 0.035), higher stroke volume (P = 0.003), large mitral E (P = 0.019) and higher E/e' (P = 0.015).

DISCUSSION

An LVOT early diastolic wave is a normal physiological finding. It is related to a flow vortex redirecting diastolic mitral inflow around anterior mitral valve leaflet into the LVOT.

CONCLUSIONS

Early to mid-diastolic LVOT waves are present in almost all patients but more prominent in young athletes than non-athletes. Diastolic LVOT waves increase with younger age, slower heart rate, larger stroke volume and enhanced diastolic function.

Quantification of cardiac and respiratory modulation of axonal activity in the human vagus nerve

We recently documented the first microelectrode recordings from the cervical vagus nerve in awake humans. Here we aimed to quantify cardiac and respiratory modulation of vagal activity to assess the feasibility of targeting axons supplying the heart and airways. Multi-unit activity was recorded from 43 sites in 19 healthy participants in the left (n = 10) and right (n = 9) vagus nerves with ECG, continuous non-invasive blood pressure and respiration. Cross-correlation histograms were constructed between axonal spikes and the R-waves or the peaks of inspiration. The latencies for the peak in cardiac modulation showed a bimodal distribution: while the majority of sites (72%) had peak latencies that preceded the R-wave by up to 550 ms (mean ± SD, -300 ± 178 ms), 12 sites had latencies of up to 250 ms following the R-wave (64 ± 87 ms). Interestingly, the majority of sites with negative latencies (68%) were found in the left nerve whereas most of those with positive latencies (75%) were found in the right. Conversely, on average the peak of respiratory modulation straddled the peak of inspiration. Sites showing respiratory modulation were more prevalent and showed stronger modulation than those with cardiac modulation: calculated for sites with modulation indices ≥15%, the median cardiac and respiratory modulation indices were 23.4% (n = 17) and 44.5% (n = 35), respectively. We conclude that, despite the fact that much of the vagus nerve supplies the gut, cardiac and respiratory modulation of vagal nerve activity can be identified through invasive recordings in awake humans. KEY POINTS: Intraneural recordings from the cervical vagus were obtained in awake humans via tungsten microelectrodes inserted into the nerve through ultrasound guidance. Cross-correlation analysis of multi-unit vagal activity revealed cardiac and respiratory modulation, from which the amplitude and latency of the peaks could be computed. The magnitude of the cardiac modulation (23%) was weaker than that of the respiratory modulation (45%). The latencies for the peak in cardiac modulation showed a bimodal distribution: the majority of sites (72%) had peak latencies that preceded the R-wave, while the remainder had latencies that followed the R-wave. The majority of sites with negative latencies (68%) were found in the left nerve whereas most of those with positive latencies (75%) were found in the right. On average the peak of respiratory modulation coincided with the peak of inspiration.

Chitosan nanoparticles facilitate improved intestinal permeation and oral pharmacokinetics of the mast cell stabiliser cromoglycate

Cromoglycate is a mast cell stabiliser typically administered via inhalation or intranasally for the treatment of allergy-based respiratory issues. Oral dosing of cromoglycate remains challenging due to its high solubility but low permeability across epithelial membranes in the gastrointestinal tract: effective formulation strategies are clearly needed. Here, we investigate and preclinically develop chitosan-cromoglycate complexes and associated nano/microparticle formulations with muco-adhesive and permeation enhancing capabilities to overcome the biopharmaceutical challenges for oral dosing.The synthesized complexes were optimized with respect to chitosan grade, particle size, and drug loading and demonstrated up to a 9.3-fold enhancement in permeability across a Caco-2 monolayer for chitosan-cromoglycate particles, compared to the pure drug. This increased intestinal permeability led to improved pharmacokinetic performance of cromoglycate, e.g. up to 1.82-fold increase in relative oral bioavailability when dosed to Sprague-Dawley rats in a fasted state. These findings confirm the potential for chitosan particles to serve as an effective oral delivery vehicle for cromoglycate, with additional formulation optimization presenting the opportunity to reduce dosing frequency for treatment of allergy-based respiratory ailments.

Screening-Guided Spironolactone Treatment of Subclinical Left Ventricular Dysfunction for Heart Failure Prevention in At-risk Patients

BACKGROUND

Subclinical left ventricular dysfunction (LVD) is a prelude to symptomatic heart failure (HF). We hypothesised that screening-guided treatment with spironolactone would prevent incident HF in at-risk patients.

METHODS

We randomised asymptomatic, community-dwelling subjects aged ≥65 years old, with at least one non-ischaemic HF risk factor (hypertension, type 2 diabetes mellitus or obesity) to echocardiography-guided therapy or usual care. Spironolactone therapy was triggered by the detection of subclinical LVD (GLS ≤16% or diastolic abnormalities (at least one of E/e'>15, E/e' >10 with left atrial enlargement [LAE] or impaired relaxation [E/A <0.8, IR], LAE with IR), or borderline GLS (17%) with IR or borderline GLS with LAE. The primary outcome was incident HF at 24 months. Secondary outcomes were change in 6-minute walk test (6MWT) and change in LV function.

RESULTS

LVD was identified in 161 (46%) of 349 participants (age 70 years [68-73], 201 (58%) women). The trial was stopped because of a 55% rate of spironolactone discontinuation, due primarily to decline in renal function. Incident HF developed in 11 (3.5%) of 310 participants completing follow-up, with no difference between usual care and intervention (4 [2.5%] vs. 7 [4.7%], p=0.29), decline in 6MWT distance (p=0.28), persistent or new LVD (p=0.58), nor change in GLS with intervention (p=0.15). A per-protocol analysis of 131 patients with baseline LVD and a follow-up echocardiogram, showed resolution of LVD with spironolactone therapy (61% vs 33%, p=0.01).

CONCLUSION

The study was underpowered to determine whether screening-guided spironolactone therapy reduced incident HF because spironolactone was frequently discontinued due to renal function criteria. However, LVD resolved in more patients treated with spironolactone than in untreated patients. Future trials should use less conservative renal criteria for spironolactone discontinuation.

Psychophysiological adjustment to formal education varies as a function of peer status and socioeconomic status in children beginning kindergarten

The transition to kindergarten can be stressful as children adjust to novel separations from their caregivers and become accustomed to their peer group. A 9-month study of 96 children (M_age  = 5.37 years, SD = 0.42) from Barranquilla, Colombia, assessed socioeconomic differences in hypothalamic-pituitary-adrenal (HPA) axis functioning across the kindergarten year. Children were from four different classrooms in one school. Saliva samples were collected twice a day across 3 consecutive days at the beginning and end of the school year. We examined whether change in HPA axis activation across the year varied as a function of a child's socioeconomic status (SES) and experience in the peer group. We found that rejected children and lower SES children had lower cortisol levels early in the morning. Rejected children had a flatter morning cortisol slope. Lower SES children had higher cortisol than their higher SES peers at the end of the school year and a flatter morning cortisol slope. Taken together, these findings suggest that diurnal cortisol in children beginning kindergarten may be influenced by both peer rejection and SES.

Tailoring interfacial effect in multilayers with Dzyaloshinskii-Moriya interaction by helium ion irradiation

We show a method to control magnetic interfacial effects in multilayers with Dzyaloshinskii-Moriya interaction (DMI) using helium (He[Formula: see text]) ion irradiation. We report results from SQUID magnetometry, ferromagnetic resonance as well as Brillouin light scattering results on multilayers with DMI as a function of irradiation fluence to study the effect of irradiation on the magnetic properties of the multilayers. Our results show clear evidence of the He[Formula: see text] irradiation effects on the magnetic properties which is consistent with interface modification due to the effects of the He[Formula: see text] irradiation. This external degree of freedom offers promising perspectives to further improve the control of magnetic skyrmions in multilayers, that could push them towards integration in future technologies.

Mimicking the Gastrointestinal Mucus Barrier: Laboratory-Based Approaches to Facilitate an Enhanced Understanding of Mucus Permeation

The gastrointestinal mucus layer plays a significant role in maintaining gut homeostasis and health, offering protective capacities against the absorption of harmful pathogens as well as commensal gut bacteria and buffering stomach acid to protect the underlying epithelium. Despite this, the mucus barrier is often overlooked during preclinical pharmaceutical development and may pose a significant absorption barrier to high molecular weight or lipophilic drug species. The complex chemical and physical nature of the dynamic mucus layer has proven problematic to reliably replicate in a laboratory setting, leading to the development of multiple mucus models with varying complexity and predictive capacity. This, coupled with the wide range of analysis methods available, has led to a plethora of possible approaches to quantifying mucus permeation; however, the field remains significantly under-represented in biomedical research. For this reason, the development of a concise collation of the available approaches to mucus permeation is essential. In this review, we explore widely utilized mucus mimics ranging in complexity from simple mucin solutions to native mucus preparations for their predictive capacity in mucus permeation analysis. Furthermore, we highlight the diverse range of laboratory-based models available for the analysis of mucus interaction and permeability with a specific focus on in vitro, ex vivo, and in situ models. Finally, we highlight the predictive capacity of these models in correlation with in vivo pharmacokinetic data. This review provides a comprehensive and critical overview of the available technologies to analyze mucus permeation, facilitating the efficient selection of appropriate tools for further advancement in oral drug delivery.

Traditional markers of cardiac toxicity fail to detect marked reductions in cardiorespiratory fitness among cancer patients undergoing anti-cancer treatment

AIMS

Left ventricular ejection fraction (LVEF) is standard of care for evaluating chemotherapy-associated cardiotoxicity, although global longitudinal strain (GLS) offers advantages. However, neither change in LVEF or GLS has been associated with short-term symptoms, functional capacity, or long-term heart failure (HF) risk. We sought to determine whether an integrative measure of cardiovascular function (VO2peak) that is strongly associated with HF risk would be more sensitive to cardiac damage induced by cancer treatment than LVEF, GLS, or cardiac biomarkers.

METHODS AND RESULTS

Patients (n = 206, 53 ± 13 years, 35% male) scheduled to commence anti-cancer treatment completed assessment prior to, and within 6 months after therapy. Changes in echocardiographic measures of LV function (LVEF, GLS), cardiac biomarkers (troponin and BNP), and cardiorespiratory fitness (VO2peak) were measured. LV function was normal prior to treatment (LVEF 61 ± 5%; GLS -19.4 ± 2.1), but VO2peak was only 88 ± 26% of age-predicted. After treatment, VO2peak was reduced by 7 ± 15% (equivalent of 7 years normal ageing, P < 0.0001) and the rates of functional disability (defined as VO2peak ≤ 18 mL/min/kg) almost doubled (15% vs. 26%, P = 0.016). In contrast, small, reductions in LVEF (59 ± 5% vs. 58 ± 5%, P = 0.03) and GLS (-19.4 ± 2.1 vs. -18.9 ± 2.2, P = 0.002) and an increase in troponin levels (4.0 ± 6.9 vs. 26.4 ± 26.2 ng/mL, P < 0.0001) were observed.

CONCLUSION

Anti-cancer treatment is associated with marked reductions in functional capacity that occur independent of reductions in LVEF and GLS. The assessment of VO2peak prior to, and following treatment may be a more sensitive means of identifying patients at increased risk of HF.

Associations of subclinical heart failure and atrial fibrillation with mild cognitive impairment: a cross-sectional study in a subclinical heart failure screening programme

OBJECTIVES

Effective identification and management of subclinical left ventricular (LV) dysfunction (LVD) and subclinical atrial fibrillation (AF) by screening elderly populations might be compromised by mild cognitive impairment (MCI). We sought to characterise the prevalence and profile of MCI and evaluate associations with LV and left atrial (LA) dysfunction and AF, in a trial of screening for subclinical LVD and AF.

DESIGN

Cross-sectional.

SETTING

Australian, community-based intervention trial.

PARTICIPANTS

Adults aged ≥65 years with ≥1 LVD risk factors without ischaemic heart disease (n=337).

OUTCOME MEASURES

The Montreal cognitive assessment (MoCA) was obtained. Subclinical LVD was defined as echocardiographic global longitudinal strain ≤16%, diastolic dysfunction or LV hypertrophy; abnormal LA reservoir strain (LARS) was defined as <24%. Subclinical AF was detected using a single-lead portable electrocardiographic device in those without pre-existing AF who gave consent (n=293).

RESULTS

Subclinical LVD was found in 155 (46%), abnormal LARS in 9 (3.6%) and subclinical AF in 11 (3.8%). MoCA score consistent with MCI (<26) was found in 101 (30%); executive function (69%) and delayed recall (93%), were the most frequently abnormal domains. Compared with normal cognition, MCI was associated with non-adherence to AF screening (25% vs 40%, p=0.01). In multivariable logistic regression modelling, educational achievement, systolic blood pressure, body mass index and waist-to-hip ratio were independently associated with MCI. However, neither subclinical AF nor any measure of cardiac dysfunction, were associated with MCI.

CONCLUSIONS

The 30% prevalence of MCI among elderly subjects with risk factors for subclinical LVD and AF has important implications for screening strategies and management. However, MCI is not associated with subclinical myocardial dysfunction nor subclinical AF.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12617000116325).

Use of echocardiography to stratify the risk of atrial fibrillation: comparison of left atrial and ventricular strain

AIMS

Although both left atrial (LA) and ventricular (LV) dysfunction has been accepted as an important risk factor of atrial fibrillation (AF), usefulness of LA and LV strain has not been fully compared for prediction of AF. The aims of this study were to clarify the associations of both LA and LV strain with AF and to compare their predictive values in the risk stratification for AF.

METHODS AND RESULTS

We evaluated 531 consecutive patients (median age 67 years, 56% male), with no history of AF who underwent echocardiography after cryptogenic stroke. Standard echocardiographic parameters were measured, and speckle-tracking was used to measure LA (reservoir, pump, and conduit strain) and LV strain (global longitudinal strain, GLS). The baseline clinical and echocardiographic parameters of the patients who developed AF and those who did not were compared. Median 36 months of follow-up, 61 patients (11%) had newly diagnosed AF. LA pump strain and GLS were significantly and independently associated with AF and provided incremental predictive value over clinical and standard echocardiographic parameters. Areas under the receiver-operating curves for GLS (0.841) were comparable to LA pump (0.825) and reservoir (0.851) strain. However, predictive value of both strains was different between patients with and without LA enlargement at the time of transthoracic echocardiography screening. LA strain was more useful than LV strain in patients with normal LA volumes, while LV strain was more useful than LA strain in patients with abnormal LA volumes.

CONCLUSION

Both LA and LV strain are significantly and independently associated with AF and provide incremental predictive value over clinical and standard echocardiographic parameters. However, priorities of strain assessment are different depends on patients' condition at the time of echocardiography.

Role of microvascular dysfunction in left ventricular dysfunction in type 2 diabetes mellitus

BACKGROUND

Although microvascular disease (mVD) has been linked to poor cardiovascular outcomes in diabetes mellitus, the contribution of mVD to diabetic cardiomyopathy (DC) is unexplored. We investigated whether LV systolic and diastolic dysfunction is associated with mVD in T2DM.

METHODS

We recruited 32 asymptomatic patients with T2DM (age 71 ± 4 years, 31% females) from a community-based population. All underwent a comprehensive echocardiogram at baseline including assessment of global longitudinal strain (GLS) and diastolic function. Adenosine stress perfusion on cardiac magnetic resonance imaging (CMR) was performed in all patients. Coronary sinus flow (CSF) was measured offline at rest and peak stress with coronary flow reserve (CFR) calculated as the ratio of global stress and rest CSF.

RESULTS

Resting CSF was reduced in 15 (47%) compared to 4 (13%) with adenosine-stress (p = 0.023). Overall, CFR was observed to be reduced in the cohort (2.38 [IQR 2.20]). Abnormal CFR was not associated with diabetes duration of ≥10 years or poor glycaemic control. CFR was not associated with abnormal GLS (OR 1.04 [95% CI 0.49, 2.20], p = 0.93). However, a modest negative correlation was observed with e' and CFR (r = -0.49, p = 0.004).

CONCLUSION

This pilot study did not show correlation between subclinical systolic dysfunction and a novel MRI biomarker of microvascular disease. However, there was a weak correlation with myocardial relaxation. Confirmation of these findings in larger studies is indicated.

A prospective STudy using invAsive haemodynamic measurements foLLowing catheter ablation for AF and early HFpEF: STALL AF-HFpEF

AIMS

The impact of atrial fibrillation (AF) ablation in early heart failure with preserved ejection fraction (HFpEF) is unknown. Our aim was to determine the impact of AF ablation on symptoms and exercise haemodynamic parameters of early HFpEF.

METHODS AND RESULTS

Symptomatic AF patients referred for index AF ablation with ejection fraction ≥50% underwent baseline quality of life questionnaires, echocardiography, cardiac magnetic resonance imaging, exercise right heart catheterisation (exRHC), and brain natriuretic peptide (BNP) testing. HFpEF was defined by resting pulmonary capillary wedge pressure (PCWP) ≥15 mmHg or peak exercise PCWP ≥25 mmHg. Patients with HFpEF were offered AF ablation and follow-up exRHC ≥6 months post-ablation. Of 54 patients undergoing baseline evaluation, 35 (65%) had HFpEF identified by exRHC. HFpEF patients were older (64 ± 10 vs. 54 ± 13 years, P < 0.01), and more frequently female (54% vs. 16%, P < 0.01), hypertensive (63% vs. 16%, P < 0.001), and suffering persistent AF (66% vs. 11%, P < 0.001), compared to those without HFpEF. Twenty HFpEF patients underwent AF ablation and follow-up exRHC 12 ± 6 months post-ablation. Nine (45%) patients no longer fulfilled exRHC criteria for HFpEF at follow-up. Patients remaining arrhythmia free (n = 9, 45%) showed significant improvements in peak exercise PCWP (29 ± 4 to 23 ± 2 mmHg, P < 0.01) and Minnesota Living with Heart Failure (MLHF) score (55 ± 30 to 22 ± 30, P < 0.01) while the remainder did not (PCWP 31 ± 5 to 30.0 ± 4 mmHg, P = NS; MLHF score 55 ± 23 to 25 ± 20, P = NS).

CONCLUSION

Heart failure with preserved ejection fraction frequently coexists in patients with symptomatic AF and preserved ejection fraction. Restoration and maintenance of sinus rhythm in patients with comorbid AF and HFpEF improves haemodynamic parameters, BNP and symptoms associated with HFpEF.

The effect of posture on maximal oxygen uptake in active healthy individuals

PURPOSE

Semi-supine and supine cardiopulmonary exercise testing (CPET) with concurrent cardiac imaging has emerged as a valuable tool for evaluating patients with cardiovascular disease. Yet, it is unclear how posture effects CPET measures. We aimed to discern the effect of posture on maximal oxygen uptake (VO₂max) and its determinants using three clinically relevant cycle ergometers.

METHODS

In random order, 10 healthy, active males (Age 27 ± 7 years; BMI 23 ± 2 kg m²) underwent a ramp CPET and subsequent constant workload verification test performed at 105% peak ramp power to quantify VO₂max on upright, semi-supine and supine cycle ergometers. Doppler echocardiography was conducted at peak exercise to measure stroke volume (SV) which was multiplied by heart rate (HR) to calculate cardiac output (CO).

RESULTS

Compared to upright (46.8 ± 11.2 ml/kg/min), VO₂max was progressively reduced in semi-supine (43.8 ± 10.6 ml/kg/min) and supine (38.2 ± 9.3 ml/kg/min; upright vs. semi-supine vs. supine; all p ≤ 0.005). Similarly, peak power was highest in upright (325 ± 80 W), followed by semi-supine (298 ± 72 W) and supine (200 ± 51 W; upright vs. semi-supine vs. supine; all p < 0.01). Peak HR decreased progressively from upright to semi-supine to supine (186 ± 11 vs. 176 ± 13 vs. 169 ± 12 bpm; all p < 0.05). Peak SV and CO were lower in supine relative to semi-supine and upright (82 ± 22 vs. 92 ± 26 vs. 91 ± 24 ml and 14 ± 3 vs. 16 ± 4 vs. 17 ± 4 l/min; all p < 0.01), but not different between semi-supine and upright.

CONCLUSION

VO₂max is progressively reduced in reclined postures. Thus, posture should be considered when comparing VO₂max results between different testing modalities.

Gender is Key: Girls' and Boys' Cortisol Differs as a Factor of Socioeconomic Status and Social Experiences During Early Adolescence

The risks associated with negative peer relationships and low socioeconomic status (SES), and how they impact diurnal cortisol and the cortisol response to negative experiences, have never been studied together in early adolescents; this study aims to fill this gap in the literature. Saliva was collected from 95 early adolescents (M_age = 10.80, SD = 0.72) and daily diaries were completed 30 min after awakening, beginning of school, 15 min after first recess, 15 min after lunch, and at the end of the school day across four consecutive days. Hierarchical Linear Modelling was used to estimate the within- and between-person variances of diurnal cortisol and the cortisol response to stress in the context of SES and peer experiences. Cortisol secretion differed by gender and was predicted by SES and social status within the peer group. Low-SES early adolescents had higher morning cortisol. Girls who were from higher SES families had the steepest diurnal cortisol slope. Non-accepted early adolescents had low cortisol in response to both positive and negative social experiences. The findings from this study clarify the impact of both SES and peer relations on early adolescent psychophysiological development.

Feasibility, Reproducibility, and Clinical Implications of the Novel Fully Automated Assessment for Global Longitudinal Strain

BACKGROUND

Despite evidence of its usefulness, measurement of global longitudinal strain (GLS) has not been widely accepted as a clinical routine, because it requires proficiency and is time consuming. Automated assessment of GLS may be the solution for this situation. The aim of this study was to investigate the feasibility, reproducibility, and predictive value of automated strain analysis compared with semiautomated and manual assessment of GLS.

METHODS

In this validation study, different methods for the assessment of GLS were applied to echocardiograms from 561 asymptomatic subjects (mean age, 71 ± 5 years) with heart failure risk factors, recruited from the community. All patients had both data on follow-up outcomes (new heart failure and cardiac death) and interpretable echocardiographic images for strain analysis. Measurement of GLS was repeated using the same apical images with three different measurement packages as follows: (1) fully automated GLS (AutoStrain), (2) semiautomated GLS (automated, corrected by a trained investigator), and (3) manual GLS (standard manual assessment by a trained investigator).

RESULTS

AutoStrain measurements were technically feasible in 99.5% of patients. Calculation times for automated (0.5 ± 0.1 min/patient) and semiautomated assessment (2.7 ± 0.6 min/patient) were significantly shorter than for manual assessment (4.5 ± 1.6 min/patient; P < .001 for both). Approximately 40% of patients were thought to need manual correction after automatic calculation of GLS. Therefore, there was considerable discordance between automated and semiautomated and manual GLS. Over a median of 12 months of follow-up, cardiovascular events (new heart failure and cardiac death) occurred in 66 patients (11.8%). Automated GLS showed the potential to correctly detect normal and abnormal systolic function and predict cardiac events; the predictive value was inferior to that of semiautomated GLS.

CONCLUSIONS

A novel fully automated assessment for GLS may provide a technically feasible, rapidly reproducible, and clinically applicable means of assessing left ventricular function, but a substantial number of automatic traces still need manual correction by experts. At the present stage, the semiautomated approach using this novel automated software seems to provide a better balance between feasibility and clinical relevance.

Evolution of Myocardial Dysfunction in Asymptomatic Patients at Risk of Heart Failure

OBJECTIVES

The determinants of changes in systolic and diastolic parameters in patients age >65 years, at risk of heart failure (HF), and with and without asymptomatic type 2 diabetes mellitus (T2DM) was assessed by echocardiography. The association between metformin and myocardial function was also assessed.

BACKGROUND

The increasing prevalence of T2DM will likely further fuel the epidemic of HF. Understanding the development or progression of left ventricular (LV) dysfunction may inform effective measures for HF prevention.

METHODS

A total of 982 patients with at least one HF risk factor (hypertension, obesity, or T2DM) were recruited from 2 community-based populations and divided into 2 groups: T2DM (n = 431, age 71 ± 4 years) and non-T2DM (n = 551, age 71 ± 5 years). Associations of metformin therapy were evaluated in the T2DM group. All underwent a comprehensive echocardiogram, including global longitudinal strain (GLS) and diastolic function (transmitral flow [E], annular velocity [e']) at baseline and follow-up (median 19 months [interquartile range: 17 to 26 months]). Comparisons were facilitated by propensity matching.

RESULTS

A reduction in GLS was observed in the T2DM group (baseline -17.8 ± 2.6% vs. follow-up -17.4 ± 2.8%; p = 0.003), but not in the non-T2DM group (-18.7 ± 2.7% vs. -18.6 ± 3.0%; p = 0.41). Estimated LV filling pressures increased in both the T2DM group (p = 0.001) and the non-T2DM group (p = 0.04). Metformin-treated patients with T2DM did not increase estimated LV filling pressure (E/e' baseline 8.9 ± 2.7 vs. follow-up 9.1 ± 2.7; p = 0.485) or change e' (7.6 ± 1.5 cm/s vs. 7.6 ± 1.8 cm/s; p = 0.88). After propensity matching, metformin was associated with a smaller change in e' (β = 0.58 [95% CI: 0.13 to 1.03]; p = 0.013) and E/e' (β = -0.96 [95% CI: -1.66 to -0.26]; p = 0.007) but was not associated with a change in GLS (p = 0.46).

CONCLUSIONS

Over 2 years, there is a worsening of GLS and LV filling pressures in asymptomatic diabetic patients with HF risk factors. Metformin use is associated with less deterioration of LV filling pressures and myocardial relaxation but had no association with systolic function.

Feasibility, reproducibility, and clinical implications of the fully automated assessment for global longitudinal strain

Background

Despite of evidence on its usefulness, measurement of global longitudinal strain (GLS) has not been widely accepted as a clinical routine because it requires proficiency and is time-consuming. Automated assessment of GLS may be a solution to these barriers. This study sought to investigate the feasibility, reproducibility, and predictive value of automated strain analysis compared with semi-automated and manual assessment for global longitudinal strain.

Methods

In this validation study, different methods for the assessment of GLS were applied to echocardiograms of 561 asymptomatic people (age 71±5 years) with heart failure (HF) risk factors, recruited from the community. All patients were followed up for new-onset of HF and cardiovascular death. Measurement of GLS was repeated using the same apical images on three different measurement packages as follows: (1) fully automated GLS (AutoStrain), (2) semi-automated GLS (automated, corrected by a trained investigator), and (3) manual GLS (standard manual assessment by a trained investigator). We defined abnormal GLS for discrimination of LV systolic dysfunction using the cut-off of GLS =18% (absolute value).

Results

AutoStrain measurements were feasible in 99.5% of patients. Calculation time for automated (0.5±0.1 min/patient) and semi-automated assessment (2.7±0.6 min/patient) were significantly shorter than that for manual assessment (4.5±1.6 min/patient) (both p&lt;0.001), and the automated assessment showed excellent reproducibility. There was considerable discordance between automated and semi-automated/manual GLS (Figure 1), but normal systolic function was reliable identified. The prediction of cardiovascular events was reliable with automated, semi-automated and manual GLS (Figure 2).

Conclusion

A novel fully automated assessment for GLS is a feasible, rapid, reproducible and clinically applicable means of assessing LV function, and measurements in the normal range predict a favorable outcome.

Figure 1

Funding Acknowledgement

Type of funding source: None

Peer relations and socioeconomic status and inequality

Although peer relations are recognized as a fundamental developmental context, they have been rarely studied as a means of understanding the effects of socioeconomic status and inequality. In this paper, we show how and why peer relations provide a unique and powerful opportunity to assess the differential risks and resources available in the peer system to children and adolescents from different SES spectra. We argue that research on the intersection between SES and peer relations will enrich both these domains of study.

A Comparison of Chitosan, Mesoporous Silica and Poly(lactic-co-glycolic) Acid Nanocarriers for Optimising Intestinal Uptake of Oral Protein Therapeutics

Efficacious oral delivery of therapeutic proteins remains challenging and nanoparticulate approaches are gaining interest for enhancing their permeability. In this study, we explore the ability for three comparably sized nanocarriers, with diverse physicochemical properties [i.e., chitosan (CSNP), mesoporous silica nanoparticles (MSNP) and poly(lactic-co-glycolic) acid (PLGA-NP)], to successfully facilitate epithelial uptake of a model protein, ovalbumin (OVA). We report the effect of nanoparticle surface chemistry and nanostructure on protein release, cell toxicity and the uptake mechanism in a Madin Darby Canine Kidney (MDCK) cell model of the intestinal epithelium. All nanocarriers exhibited bi-phasic OVA release kinetics with sustained and incomplete release after 4 days, and more pronounced release from MSNP than either polymeric nanocarriers. CSNP and MSNP displayed the highest cellular uptake, however CSNP was prone to significant dose-dependent toxicity attributed to the cationic surface charge. Approximately 25% of MSNP uptake was governed by a clathrin-independent endocytic mechanism, while CSNP and PLGA-NP uptake was not controlled via any endocytic mechanisms investigated herein. Furthermore, endosomal localisation was observed for CSNP and MSNP, but not for PLGA-NP. These findings may assist in the optimal choice and engineering of nanocarriers for specific intestinal permeation enhancement for oral protein delivery.

Measurement of Functional Capacity to Discriminate Clinical from Subclinical Heart Failure in Patients ≥65 Years of Age

In order to show that reduced functional capacity in subclinical heart failure portends a higher risk of clinically overt (stage C) heart failure, we obtained the Duke activity status index (DASI) and 6-minute walk distance (6MWD) in 814 patients (age 70 [interquartile range 67 to 74] years, 51% female) with nonischemic subclinical heart failure. Reduced functional capacity was defined as: (1) DASI-derived metabolic equivalents <7, (2) 6MWD <2 standard deviations below the age-based normative mean (excluding those with mobility impairment) and (3) reduced 6MWD with reclassification where DASI was discordant. Based on reduced functional capacity and left ventricular dysfunction (LVD), subjects were classified into; (1) Stage A heart failure (436 with neither LVD nor reduced functional capacity), (2) Stage A with reduced functional capacity (n = 80), (3) Stage B heart failure (182 with LVD but preserved functional capacity) and (4) early stage C heart failure (52 with LVD and reduced functional capacity). Outcome was assessed by Kaplan-Meier survival estimates and Cox proportional hazard ratios. After a median follow-up of 13 months [interquartile range 11 to 19]), 76 (9%) developed heart failure - 6% of Stage A, 10% of Stage A-reduced functional capacity, 9% of Stage B and 37% of early Stage C (p < 0.001). After adjustment (for heart failure risk score, atrial fibrillation, pulmonary disease and therapy), the hazard ratio for development of overt heart failure in early Stage C was 5.92 (95% confidence intervals 2.92 to 11.54, p < 0.001) compared with Stage A and 3.08 (95% confidence intervals 1.47 to 6.47, p = 0.003) compared with Stage B.

In vivo recordings from the human vagus nerve using ultrasound-guided microneurography

KEY POINTS

The vagus nerve is the largest cranial nerve and innervates many structures in the neck, thorax and abdomen. Although single-unit recordings from the vagus nerve have been performed in experimental animals for several decades, no recordings have ever been made from the human vagus nerve. The vagus nerve is routinely stimulated clinically, yet we know little of its physiology in humans. We describe the methodology and provide preliminary results of the first intraneural single-unit recordings from the cervical vagus in awake humans, using tungsten microelectrodes inserted into the nerve through ultrasound guidance.

ABSTRACT

Intraneural microelectrodes have been used extensively to record from single somatosensory axons supplying muscle, tendons, joints and skin, as well as to record from postganglionic sympathetic axons supplying muscle and skin, in accessible peripheral nerves in awake humans. However, the vagus nerve has never been targeted, probably because of its close proximity to the carotid artery and jugular vein in the neck. Here, we report the first unitary recordings from the human cervical vagus nerve, obtained using ultrasound-guided insertion of tungsten microelectrodes into fascicles of the nerve. We identified tonically-active neurones in which firing rates were inversely related to heart rate (and directly related to the cardiac interval), which we classified as putative preganglionic parasympathetic axons directed to the sinoatrial node of the heart. We also recorded from tonically-active presumed sensory axons from the airways and presumed motor axons to the larynx. This new methodology opens exciting new opportunities for studying the physiology of the human vagus nerve in health and disease.