Pain trajectories and neuropathic pain symptoms following lung cancer surgery: A prospective cohort study

BACKGROUND

Persistent postsurgical pain (PPSP) after lung cancer surgery is common and current definitions are based on evaluations at a single time point after surgery. Pain intensity and symptoms may however fluctuate and change over time, and be impacted by multiple and shifting factors. Studies of postoperative recovery patterns and transition from acute to chronic pain are needed for further investigation of preventive measures and treatments to modify unfavourable recovery paths.

METHODS

In this explorative study, 85 patients undergoing surgery due to either presumptive or confirmed lung cancer reported pain intensities bi-monthly for 12 months. Pain trajectories during recovery were investigated, using group-based trajectory modelling. Associations with possible risk factors for PPSP, including clinical variables and anxiety and depression score (HADS), were also explored.

RESULTS

A trajectory model containing three 12-month pain recovery groups was computed. One group without PPSP fully recovered (50%) within two to three months. Another group with mild-intensity PPSP followed a protracted recovery trajectory (37%), while incomplete recovery was observed in the last group (13%). Acute postoperative pain and younger age were associated with a less favourable recovery trajectory. More neuropathic pain symptoms were observed in patients with incomplete recovery.

CONCLUSIONS

Three clinically relevant recovery trajectories were identified, based on comprehensive pain tracking. Higher acute postoperative pain intensity was associated with an unfavourable pain recovery trajectory.

SIGNIFICANCE STATEMENT

Understanding the transition from acute to chronic postoperative pain and identifying preoperative risk factors is essential for the development of targeted treatments and the implementation of preventive measures. This study (1) identified distinct recovery trajectories based on frequent pain assessment follow-ups for 12 months after surgery and (2) evaluated risk factors for unfavourable postoperative pain recovery paths. Findings suggest that early higher postoperative pain intensity is associated with an unfavourable long-term recovery path.

Yearly intrasubject variability of hematological biomarkers in elite athletes for the Athlete Biological Passport

Confounding factors including exercise and environments challenge the interpretation of individual Athlete Biological Passports (ABPs). This study aimed to investigate the natural variability of hematological ABP parameters over 1 year in elite athletes compared with healthy control subjects and the validity of a multiparametric model estimating plasma volume (PV) shifts to correct individual ABP thresholds. Blood samples were collected monthly with full blood counts performed by flow cytometry (Sysmex XN analyzers) in 20 elite xc-skiers (ELITE) and 20 moderately trained controls. Individual ABP profiles were generated through Anti-Doping Administration & Management System Training, a standalone version of the ABP's adaptive model developed by the World Anti-Doping Agency. Additionally, eight serum parameters were computed as volume-sensitive biomarkers to run a multiparametric model to estimate PV. Variability in ELITE compared with controls was significantly higher for the Abnormal Blood Profile Scores (P = 0.003). Among 12 Atypical Passport Findings (ATPF) initially reported, six could be removed after correction of PV shifts with the multiparametric modeling. However, several ATPF were additionally generated (n = 19). Our study outlines a larger intraindividual variability in elite athletes, likely explained by more frequent exposure to extrinsic factors altering hematological biomarkers. PV correction for individual ABP thresholds allowed to explain most of the atypical findings while generating multiple new ATPF occurrences in the elite population. Overall, accounting for PV shifts in elite athletes was shown to be paramount in this study outlining the opportunity to consider PV variations with novel approaches when interpreting individual ABP profiles.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Repeated deep-inspiration breath-hold CT scans at planning underestimate the actual motion between breath-holds at treatment for lung cancer and lymphoma patients

PURPOSE/OBJECTIVE

Deep-inspiration breath-hold (DIBH) during radiotherapy may reduce dose to the lungs and heart compared to treatment in free breathing. However, intra-fractional target shifts between several breath-holds may decrease target coverage. We compared target shifts between four DIBHs at the planning-CT session with those measured on CBCT-scans obtained pre- and post-DIBH treatments.

MATERIAL/METHODS

Twenty-nine lung cancer and nine lymphoma patients were treated in DIBH. An external gating block was used as surrogate for the DIBH-level with a window of 2 mm. Four DIBH CT-scans were acquired: one for planning (CTDIBH3) and three additional (CTDIBH1,2,4) to assess the intra-DIBH target shifts at scanning by registration to CTDIBH3. During treatment, pre-treatment (CBCTpre) and post-treatment (CBCTpost) scans were acquired. For each pair of CBCTpre/post, the target intra-DIBH shift was determined. For lung cancer, tumour (GTV-Tlung) and lymph nodes (GTV-Nlung) were analysed separately. Group mean (GM), systematic and random errors, and GM for the absolute maximum shifts (GMmax) were calculated for the shifts between CTDIBH1,2,3,4 and between CBCTpre/post.

RESULTS

For GTV-Tlung, GMmax was larger at CBCT than CT in all directions. GMmax in cranio-caudal direction was 3.3 mm (CT)and 6.1 mm (CBCT). The standard deviations of the shifts in the left-right and cranio-caudal directions were larger at CBCT than CT. For GTV-Nlung and CTVlymphoma, no difference was found in GMmax or SD.

CONCLUSION

Intra-DIBH shifts at planning-CT session are generally smaller than intra-DIBH shifts observed at CBCTpre/post and therefore underestimate the intra-fractional DIBH uncertainty during treatment. Lung tumours show larger intra-fractional variations than lymph nodes and lymphoma targets.

Development of Cycling Performance Variables and Durability in Female and Male National Team Cyclists: From Junior to Senior

AIM

This study investigated the development of power profiles and performance-related measures from the junior level (<19 yr) via U23 (19-23 yr) to senior level (>23 yr) in 19 female and 100 male Norwegian national team cyclists.

METHODS

A total of 285 tests were performed in a 3-d laboratory-standardized testing regime. The tests included power profiles with shorter duration (6-60 s) and longer durations (12-30 min) together with performance-related measures: critical power (CP), work capacity above CP (W'), power output at 4 and 2 mmol·L -1 [BLa - ] (L 4 and L 2 ), maximal aerobic power (W max ), and maximal oxygen uptake (V̇O 2max ), gross efficiency (GE), and pedaling efficiency.

RESULTS

Females and males evolve similarly when maturing from junior via U23 to senior categories (all P > 0.07), except for V̇O 2max , which increased in females (but not males) from junior to senior level (534 ± 436 mL·min -1 , P = 0.013). In general, only performances of longer durations improved with age (12 and 30 min, P = 0.028 and P = 0.042, respectively). Performance-related measures like W max , V̇O 2max , CP, L 4 , L 2 , and pedaling efficiency in the fresh state improved with age (all P ≤ 0.025). Importantly, performance in the semifatigued state during a 5-min maximal test was also improved with age ( P = 0.045) despite a higher external energy expenditure before the test ( P = 0.026).

CONCLUSIONS

Junior cyclists show highly developed sprint abilities, and the primary improvements of absolute power outputs and performance-related measures are seen for durations >60 s when maturing to U23 and senior categories. However, the durability, i.e., the capacity to maintain performance in a semifatigued state, is improved with age.

Validation of a clinically applicable device for fast and accurate quantification of blood volume

INTRODUCTION

Determination of blood volume (BV) using the dual-isotope (e.g., ^99m Tc-labeled red blood cells [^99m Tc-RBC] and ¹²⁵ I-labeled human serum albumin [¹²⁵ I-HSA]) injection method is limited in medicine due to the long isotope half-life. However, BV has been determined in laboratory settings for 100 years using the carbon monoxide (CO)-rebreathing-based procedure, which allows frequent BV measurements.

METHODS

We investigated the reliability and accuracy of a semi-automated CO-rebreathing device by comparing it against the dual-isotope methodology and its ability to detect a known blood removal. In study A, BV was determined three times in ~2 h; twice using the device with rebreathing protocols lasting 2 (CO_2min ) and 10 min (CO_10min ) and once with the dual-isotope technique. In study B, the accuracy of the device was assessed by its ability to detect a 2% removal of BV.

RESULTS

A good correlation was observed between both the CO-rebreathing protocols (r²  = 0.89-0.98; p < 0.001) and the dual-isotope approach (r²  = 0.89-0.95; p < 0.001). In absolute terms BV was 425 ± 263 mL and 491 ± 388 mL lower (p < 0.001) when quantified with the dual-isotope compared to the CO-rebreathing protocols. When reducing BV by 132 ± 25 mL (2%), the device quantified a lower (p < 0.001) BV of 150 ± 45 mL.

CONCLUSION

This study emphasizes that the semi-automated device accurately determines small changes (i.e., 2%) in BV and that a high correlation with the dual-isotope methodology exists. The findings are clinically relevant owing to the method's simple and fast nature (the absence of radioactive tracers and reduced time requirements, i.e., ~15 min vs. ~180 min) and the possibility for repeated measurements within a single day.

Hematological, skeletal muscle fiber and exercise performance adaptations to heat training in elite female and male cyclists

Heat exercise training may increase exercise performance in athletes. The underlying mechanisms remain partly unresolved, and it is unknown if female and male athletes may experience comparable gains. The aims were to investigate whether heat training (HEAT) increases hemoglobin mass (Hb_mass), skeletal muscle fiber characteristics and thermoneutral exercise performance in elite female and male endurance athletes. Female (n=20; VO₂max = 58.2 ± 6.7 ml.min.kg) and male (n=27; VO₂max = 76.4 ± 7.8 ml.min.kg) cyclists were studied before and after five weeks of randomized control or HEAT training consisting of five weekly sessions each of 50 min duration which were included in their normal training regimes. Overall, the observed relative responses to HEAT were largely similar in female and male study participants. HEAT increased (P<0.05) Hb_mass in female from 650 ± 77 to 675 ± 76 g (4.0 ± 1.6%) and from 1008 ± 155 to 1041 ± 147 g (3.5 ± 2.3%) in male. In contrast, skeletal muscle citrate synthase activity, fiber type distribution and capillary density remained unchanged with HEAT. Lactate threshold, VO₂max and mean power output during 15 min all out testing were all enhanced (P<0.05) following HEAT in female and male study participants. In conclusion, five weeks of HEAT increases Hb_mass in female and male elite cyclists and improves exercise performance in a thermoneutral environment. Based on this, heat training may be recommended to elite female and male athletes aiming to perform in a thermoneutral environment.

A 6-day high-intensity interval microcycle improves indicators of endurance performance in elite cross-country skiers

Purpose

The aim of this study was to compare the effects of a 6-day high-intensity interval (HIT) block [BLOCK, n = 12, maximal oxygen uptake (V̇O2max = 69. 6 ± 4.3 mL·min−1·kg−1)] with a time-matched period with usual training (CON, n = 12, V̇O2max = 69.2 ± 4.2 mL·min−1·kg−1) in well-trained cross-country (XC) skiers on physiological determinants and indicators of endurance performance. Furthermore, the study aimed to investigate the acute physiological responses, including time ≥90% of V̇O2max, and its associated reliability during repeated HIT sessions in the HIT microcycle.

Methods

Before the 6-day HIT block and following 5 days of recovery after the HIT block, both groups were tested on indicators of endurance performance. To quantify time ≥90% of V̇O2max during interval sessions in the HIT block, V̇O2 measurements were performed on the 1st, 2nd, and last HIT session in BLOCK.

Results

BLOCK had a larger improvement than CON in maximal 1-min velocity achieved during the V̇O2max test (3.1 ± 3.1% vs. 1.2 ± 1.6%, respectively; p = 0.010) and velocity corresponding to 4 mmol·L−1 blood lactate (3.2 ± 2.9% vs. 0.6 ± 2.1%, respectively; p = 0.024). During submaximal exercise, BLOCK displayed a larger reduction in respiratory exchange ratio, blood lactate concentration, heart rate, and rate of perceived exertion (p &lt; 0.05) and a tendency towards less energy expenditure compared to CON (p = 0.073). The ICC of time ≥90% V̇O2max in the present study was 0.57, which indicates moderate reliability.

Conclusions

In well-trained XC skiers, BLOCK induced superior changes in indicators of endurance performance compared with CON, while time ≥90% of V̇O2max during the HIT sessions in the 6-day block had a moderate reliability.

Dual-chamber paced patients without high-degree AV block at baseline are at higher risk of atrial arrhythmias when inappropriately paced in the right ventricle: a sub-analysis of the EMERALD study

Background/Introduction

Unnecessary right ventricular pacing (RVP) can have deleterious effects including an increased risk of atrial arrhythmia (AA) and heart failure during follow-up (FU) in dual-chamber (DR) paced patients. While previous studies have shown that these increased risks occur with RVP&gt;40%, the EMERALD Study demonstrated an increased risk for RVP&gt;1%. Few data exist on the interaction between the amount of RVP and the presence/absence of high-degree atrio-ventricular block (AVB) as a pacing indication at baseline.

Purpose

The EMERALD (AssEssment of CoMorbiditiEs & Atrial ArRhythmiA Burden In DuaL-Chamber PaceD Patients) Study was a real-world registry designed to assess the impact of RVP burden on the risk of developing persistent/permanent AA (Pers-AA) over 2-year FU. The primary endpoint was the difference in Pers-AA in subjects with high (&gt;40%) and low (&lt;40%) RVP. This sub-analysis aimed to identify the interaction between RVP and the presence/absence of high-degree AVB at baseline in relation to the incidence of Pers-AA.

Methods

EMERALD was a non-interventional, prospective, multi-center registry conducted at 186 centers in 12 countries. Enrolled subjects were implanted with a DR pacemaker according to ESC or ACC/AHA/HRS guidelines. Subjects were excluded if they had a history of Pers-AA. Devices could be implanted as de-novo, replacement or upgrade therapy. Programming was left to the investigators' discretion. Subjects were followed for at least 24 months. Pers-AA was defined as: &gt;22 h/day of AA for &gt;7 consecutive days; Pers-AA diagnosed during any FU visit; AA-related ablation or cardioversion carried out in the FU period. We compared the incidence of Pers-AA between subjects with (n=1529) and without (n=1948) high-degree AVB as a baseline pacing indication.

Results

Eligible FU data were available for n=3477 subjects. The overall population was nearly evenly split - High RVP (47.7%) and Low RVP (52.3%). In the High RVP group, 11.7% experienced at least one Pers-AA episode versus 9.1% in the Low RVP group (p=0.006). In this sub-analysis, the prevalence of RVP&gt;40% was higher in patients with high-degree AVB at baseline (74% vs 26%). Although the incidence of Pers-AA was similar in the group with high-degree AVB at baseline (High RVP 8.7% vs Low RVP 7.4%), in the group without high-degree AVB at baseline, those with High RVP developed a significantly higher incidence of Pers-AA (High RVP 18.2% vs Low RVP 9.5%, p value for interaction 0.0275; Figure 1). An analysis with a newly identified RVP threshold of 1% confirmed a high incidence of Pers-AA only in the group without high-degree AVB at baseline (18% vs 3.5%, p value for interaction 0.2265; Figure 2).

Conclusions

The baseline pacing indication sub-analysis of the EMERALD Study shows that patients without high-degree AVB as a baseline indication are at highest risk of Pers-AA. Efforts should be made to avoid any unnecessary RVP in this subgroup of patients.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): MicroPort CRM (Clamart, France)

Long-term risk of replacement of cardiovascular implantable electronic devices following external cardioversion

Introduction

External cardioversion (ECV) with transthoracic shock is a recommended and important part of the rhythm control strategy regardless of cardiovascular implantable electronic devices (CIED). Studies and case reports have demonstrated rare, but serious CIED malfunctions related to the ECV procedure. However, follow-up data on contemporary CIEDs undergoing ECV procedures are limited. The aim of this study is to investigate the long-term risk of generator replacements following an ECV procedure.

Methods

All CIED implants and surgical re-interventions in Denmark were identified in the Danish Pacemaker and ICD Register from January 2005 to April 2021. The ECV procedures were identified in the Danish National Patient Registry from January 2010 to February 2019. For each patient undergoing ECV, five matched (age, sex, and type of CIED) controls without previous ECV were identified. Time to generator replacement was estimated using competing risk analyses, with death, extraction and up-/down-grade being competing events. Risks were estimated by the pseudo-observation method.

Results

We identified in total 3,924 ECV-events in 2,610 CIED patients with 74.4% male. Mean age of patients at first ECV-procedure were 68.6±11.7 years, and median implant time was 1.5 year. The type of CIED included 50% of pacemakers, 28% of Implantable Cardioverter Defibrillators, and 22% of Cardiac Resynchronization Therapy-systems. During the first 5 years of follow-up, 451 (17.3%) of the shock-exposed devices were replaced vs. 2,000 (15.2%) of the unexposed devices. The relative risks (RR) of device replacement were 1.43 (95% CI: 0.5; 2.4) after 12 months, 1.44 (95% CI: 0.1; 2.8) after 24 months, and −0.53 (95% CI: −2.8; 1.7) after 5 years. The cumulated incidence of first endpoint: Replacement, death, extraction, and up-/down-grade are illustrated in Figure 1. A larger proportion of patients died in the shock-exposed group with n=427 (16.4%) compared to n=1,588 (12.2%) in the unexposed group during 5-years of follow-up with RR=3.2 (95% CI: 1.2; 5.3) of dead before other events.

Conclusion

Contemporary CIEDs do not indicate different risk of generator replacement following external cardioversion with transthoracic shocks. Shock-exposed device patients were more prone for extraction and death.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): This is work was financed by Department of Cardiology, Aalborg University Hospital and supported by Karl G. Andersen foundation.

A-19 Distress Predicts Poorer Cognitive Performance At Post-Injury In Concussed Athletes

Purpose: This study evaluated the consistency between athletes’ self-reported cognitive symptoms and cognitive test performance. Methods: The sample included 784 Canadian Football League athletes who underwent standardized cognitive testing with cognitive testing (ImPACT) and the Brief Symptom Inventory (BSI-18) at baseline. Over 2 consecutive seasons, 46 players were diagnosed with concussions following assessment with team physicians within 48 hours; 10 were eliminated due to missing data. Five cognitive symptoms (feeling slowed down, feeling in a fog, not feeling right, difficulties concentration, difficulties with memory) were used to create a composite score (Cog). The Cog index, the depression, anxiety, total index scores from the BSI, and the 5 ImPACT cognitive domains were correlated at baseline and post-injury. History of learning disabilities, ADHD, psychiatric diagnosis, and history of concussion were co-variates. Results: There were no significant correlations between Cog, depression, anxiety or total BSI scores and the ImPACT cognitive domains at baseline. At post injury there were no significant correlations between Cog or ImPACT index scores. In contrast, significant negative correlations were found between BSI Anxiety and verbal memory (r = 0.67, p &lt; 0.01), visual memory (r = 0.68, p &lt; 0.01), and visual-motor processing speed (r = 0.48, p &lt; 0.05). In addition, there were significant negative correlations between the BSI total score and visual memory (r = 0.51, p &lt; 0.05) and reaction time (r = 0.55, p &lt; 0.05). Conclusions: Self-reported cognitive difficulties do not correlate with poorer cognitive outcomes in our sample of professional football players. However, distress at post-injury was significantly correlated to performance, suggesting psychological variables may play a role in cognitive functioning.

A-37 Ocular Motor Impairments in Concussion Professional Football Players

Purpose: The purpose of this study was to examine baseline and post-concussion injury characteristics of ocular eye movements using the Sync Think visual eye tracking apparatus in professional football players in the Canadian Football League (CFL). Methods: The visual tracking testing protocol uses an integrated stimulus presentation-eye tracking apparatus (EyeLink CL; SR Research, Ontario, Canada) with which eye movements were recorded at 500 Hz using infrared video-oculography. The standard deviation of radial errors (SDRE) and tangential errors (SDTE) were used to determine poor visual tracking. Participants were (n = 748) rostered players in the Canadian Football League. All participants completed assessments at baseline. Sixteen players completed post-concussion assessments and 98 players completed post-exertional assessments during the 2021 season to evaluate the impact of physical exertion on ocular movement metrics. Results: Participants with diagnosed concussions (n = 16+) demonstrated significantly poorer performance on measures of both gaze stability and smooth pursuit (p &lt; 0.001). The poorer results were correlated with significantly higher subjective ratings of dizziness (p &lt; 0.01) and fogginess (p &lt; 0.001). In contrast, healthy participants who completed the same ocular motor assessments demonstrated no significant differences compared to baseline test performance. Conclusions: Findings suggest that subtle differences in oculomotor functioning arise from sport concussion in professional football players. Further research with larger sample sizes and correlation with other cognitive and physical outcomes is warranted.

A-12 Mental Health Outcomes for CFL Athletes with ADHD

Purpose: Current research suggests that athletes with Attention Deficit Hyperactivity Disorder (ADHD) are at risk for poorer outcomes arising from sport related concussions (SRC). There is limited research related evaluating mental health outcomes in athletes diagnosed with ADHD. The purpose of the study is to evaluate mental health outcomes among Canadian Football League (CFL) athletes with (ADHD) and to measure outcomes based upon a history of concussion. Methods: Professional football players from the CFL (n = 784) were administered a baseline mental health measure, the Health-Related Quality of Life (HRQL), as a component of pre-season evaluations as part of a larger cohort study (Active Rehabilitation). Diagnosis of ADHD was the independent variable and HRQL index scores measuring physical functioning, depression, cognitive functioning, were dependent variables. A second analysis compared ADHD athletes with no history of concussion to those with a history of concussion on the HRQL indexes. Results: Participants diagnosed with ADHD (n = 80) had statistically significant differences on the Physical Functioning (t(782) = −3.359, p &lt; 0.001), Depression ((t(782) = −2.820, p = 0.002) and Cognitive (t(782) = −3.570, p &lt; 0.001) domains of the HRQL, compared to athletes without ADHD. Among the athletes who are diagnosed with ADHD, no mental health differences were found between those who have at least one concussion and those who do not. Conclusions: This study did not find a significant effect of concussion on mental health outcomes in participants with ADHD. However, athletes with ADHD present with higher mental health symptoms which may merit closer monitoring.

Heat suit training increases hemoglobin mass in elite cross-country skiers

Purpose

The primary purpose was to test the effect of heat suit training on hemoglobin mass (Hb_mass) in elite cross‐country (XC) skiers.

Methods

Twenty‐five male XC‐skiers were divided into a group that added 5 × 50 min weekly heat suit training sessions to their regular training (HEAT; n = 13, 23 ± 5 years, 73.9 ± 5.2 kg, 180 ± 6 cm, 76.8 ± 4.6 ml·min⁻¹·kg⁻¹) or to a control group matched for training volume and intensity distribution (CON; n = 12, 23 ± 4 years, 78.4 ± 5.8 kg, 184 ± 4 cm, 75.2 ± 3.4 ml·min⁻¹·kg⁻¹) during the five‐week intervention period. Hb_mass, endurance performance and factors determining endurance performance were assessed before and after the intervention.

Results

HEAT led to 30 g greater Hb_mass (95% CI: [8.5, 51.7], p = 0.009) and 157 ml greater red blood cell volume ([29, 285], p = 0.018) post‐intervention, compared to CON when adjusted for baseline values. In contrast, no group differences were observed for changes in work economy, running velocity, and fractional utilization of maximal oxygen uptake (V̇O_2max) at 4 mmol·L⁻¹ blood lactate, V̇O_2max or 15‐min running distance performance trial during the intervention.

Conclusion

HEAT induced a larger increase in Hb_mass and red blood cell volume after five weeks with five weekly heat suit training sessions than CON, but with no detectable group differences on physiological determinants of endurance performance or actual endurance performance in elite CX skiers.

POS0423 CYCLIC CITRULLINATED PEPTIDE APTAMER TREATMENT ATTENUATES COLLAGEN INDUCED ARTHRITIS

Background

Anti-citrullinated peptide antibodies (ACPA) appear 10–15 years before the diagnosis of rheumatoid arthritis (RA) and are associated with a more severe disease course. In previous work, we rationally designed and screened ACPA-binding peptide aptamer sequences in silico and constructed a nanoparticle with chitosan and hyaluronic acid(1). A developmental stage version of this nanoparticle was able to reduce disease activity in the collagen-induced arthritis (CIA) and the serum transfer arthritis mouse models (2).

Objectives

Here, we investigated the effect and potential toxicity of three different versions of the aptamer nanoparticle (loading of 20%, 10% and 5% aptamer, respectively) in the CIA rat model.

Methods

Wistar rats (males and females) were given a single intravenous dose (100 mg/kilo) of type II collagen in PBS in the tail vein. The dosing was repeated three times with one day interval, followed by blood sample collection at day 7 after the initial collagen injection. To evaluate route of administration and dosing, we injected a single intravenous and subcutaneous dose (2.5 mg/kg) of aptamer-nanoparticles (A/N ratio 20%) in PBS in the tail vein/abdomen, and plasma concentration−time profiles were followed for 2 days after dosing with weekly blood sampling. To evaluate organ uptake, rats were given a single intravenous and subcutaneous dose (2.5 mg/kg) of aptamer-nanoparticles (A/N ratio 20%) in PBS in the tail vein/abdomen. The procedure was repeated after 24 hours. Blood and urine samples were taken once a week. A group of 10 animals was sacrificed every week over a three-week period, and the organs were processed. To examine efficacy, rats were given a single subcutaneous dose (2.5 mg/kilo) of aptamer-nanoparticles and nanoparticle controls without aptamer or PBS alone in the abdomen. The procedure was repeated once a week over a course of three weeks. Weight, joint measurement, blood, and urine samples were taken once a week. Paw swelling was measured on a weekly basis. In the plasma samples we measured CPEP2 and anti-collagen II by enzyme linked immunosorbent assay (ELISA).

Results

Using a rather high dose of collagen (100 mg/kilo) via an intravenous administration route, ACPA was measurable in all CIA rats with rapid development of RA in 82% of the included animals. Intravenous administration resulted in an immediate high plasma concentration post injection, which decreased rapidly to low levels. The s.c. administration route gave a steady, long-term aptamer release with a maximum availability 8 hours post-injection. After three aptamer-nanoparticle doses (2.5 mg/kg; either 20%, 10% or 5% aptamer), we observed a dose-dependent reduction in swollen joint count for the aptamer-nanoparticle treated groups (10 rats in each group) compared with the healthy control group (10 rats) (P-value = 2,1E-6). We observed decreased ACPA IgG levels in the rats treated with aptamer-nanoparticle. The decrease in ACPA levels correlated with the aptamer-nanoparticle having higher loading. Anti-collagen II IgG levels slightly increased towards the end of the study.

Conclusion

We developed and tested a novel peptide aptamer-based drug candidate for seropositive rheumatoid arthritis in CIA rats. Over a 3-week course of treatment with subcutaneous administration of aptamer-nanoparticles, joint swelling was decreased during treatment, and completely reversed at the end of the observation period. The reduction of joint swelling was associated with decreased levels of ACPA in the blood.

References

[1]Khatri S, Hansen J, Mendes AC, et al. Citrullinated Peptide Epitope Targets Therapeutic Nanoparticles to Human Neutrophils. Bioconjug Chem. 2019;30(10):2584-2593. doi:10.1021/acs.bioconjchem.9b00518

[2]Khatri S, Hansen J, Clausen MH, et al. LB0002 A FIRST IN CLASS THERAPEUTIC NANOPARTICLE FOR SPECIFIC TARGETING OF ANTI-CITRULLINATED PROTEIN ANTIBODY AMELIORATES SERUM TRANSFER AND COLLAGEN INDUCED ARTHRITIS. Annals of the Rheumatic Diseases 2020;79:212.

Disclosure of Interests

Sangita Khatri: None declared, Jonas Hansen: None declared, Nadia Pedersen: None declared, Sanne Gram-Nielsen: None declared, Ana Mendes: None declared, Ioannis Chronakis: None declared, Ulrik Keiding: None declared, Bence Réthi: None declared, Mads Hartvig Clausen Shareholder of: affiliated with IBIO TECH ApS, Tue Wenzel Kragstrup Shareholder of: affiliated with IBIO TECH ApS, Speakers bureau: TWK received speaking fees from Pfizer, Bristol-Myers Squibb, Eli Lilly, Novartis, UCB, and Abbvie., Consultant of: Consultancy fees from Bristol-Myers Squibb and Gilead, Grant/research support from: Received research grant from Gilead, Kira Astakhova Shareholder of: KA is affiliated with iBio tech.

External cardioversion of atrial fibrillation and flutter in patients with cardiac implantable electrical devices

Funding Acknowledgements

Type of funding sources: None.

Introduction

Atrial tachyarrhythmias are often treated with external cardioversion (ECV) with direct current shocks in patients with potentially electrically sensitive cardiovascular implantable electronic devices (CIED). Long-term follow-up data on contemporary pacemakers and implantable cardioverter defibrillators (ICD) undergoing ECV is sparsely described. This study investigated shock-related complications and impact on CIEDs.

Methods

All ECV procedures of atrial fibrillation and flutter from 2010 to 2020 in patients with CIED performed at a tertiary hospital (Denmark) were identified in the Danish National Patient Registry. Data on device interrogation before and after ECV and procedure-related complications were retrieved retrospectively by review of medical records.

Results

We analysed 664 ECV-events performed in 362 CIEDs, median implant time 1.5 year. Mean age of patients at first ECV-event were 69.4±9.7 years and 72.2% were men. We identified two cases of major programming changes and two cases of premature battery depletion (≤3 years after generator implant) following ECV. Minor shock-related device changes were found for impedances, atrial sensing values and pacing thresholds of right ventricle lead. In two cases increased pacing threshold of right ventricle leads following ECV triggered exit-blocks after few months. No patients died due to shock-related device dysfunctions.

Conclusion

Following external cardioversion with transthoracic direct current shocks, sporadic (&lt;1%) but potentially critical changes in device function were identified in patients with contemporary pacemakers and implantable cardioverter-defibrillators. The present study suggests that routine post-cardioversion device interrogation is imperative for patient safety.

Recurrence rates of atrial fibrillation ablation according to body mass Index, a nationwide, registry-based danish study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Novo Nordisk supported the project.

Background

The proportion of people with obesity is rapidly rising, and the number of overweight patients undergoing ablation for atrial fibrillation (AF) is also increasing. The link between body mass index (BMI), and AF prevalence is well-established but the impact of BMI on the risk of recurrent AF after ablation is less elucidated. Therefore, data pertaining to recurrence rates of ablations according to BMI in large, unselected cohorts of patients is still warranted.

Purpose

To examine the risk of recurrent AF after AF ablation by BMI.

Method

Using Danish nationwide registries, all Danish patients above 18 years who underwent first-time AF ablation from January 1st 2010 to December 31st 2018 were identified and included at the date of ablation. The patients were categorized by BMI; underweight: &lt; 18.5 kg/m2; normal weight: 18.5-24 kg/m2; overweight 25-29 kg/m2; obese 30-34 kg/m2; morbidly obese &gt; 34 kg/m2. Recurrent AF was defined using a composite endpoint comprising claimed prescriptions of anti-arrhythmic drugs, hospital admissions due to AF, re-ablation, or electrical cardioversions. The cumulative incidence of recurrent AF by BMI at 1- and 5-year follow-up after a blanking period of 90 days, was estimated using the Aalen-Johansen estimator, takin death as competing risk in to account. The relative rates of recurrent AF by BMI were examined using Cox models adjusted for sex, age, procedure-year, heart failure, ischemic heart disease, chronic obstructive pulmonary disease, chronic kidney disease, hypertension, and diabetes.

Results

The study cohort consisted of 9,229 patients. Median age [IQR] decreased from 64 [60, 75] in the normal weight group to 60 [53, 66] in the morbidly obese. The number of patients with a CHA2DS2-VASc score of 2 or more increased from 48% in normal-weight to 65% in morbidly obese. Use of amiodarone increased by BMI category, while the use of Class 1C anti-arrhythmic medication remained stable.

Figures 1 and 2 show the 1- and 5-year cumulative incidence of recurrent AF, Hazard Ratios (HR), and 95% Confidence Intervals (CI 95%) stratified by BMI categories and depict that the risk of recurrent AF increased incrementally and significantly in overweight groups compared to normal weight patients, both in 1- and 5-year follow-up. Underweight patients demonstrated non-significantly increased risk of recurrent AF, both in 1- and 5-year follow-up.

Conclusion

In this large nationwide study examining recurrent AF post AF ablation, we found that recurrence rates of AF increased incrementally according to BMI, both in short- and long-term follow-up. Therefore, aggressive weight management in overweight patients could potentially provide substantial benefits and improve short- and long-term outcomes after ablation.

Computational design of mechanically coupled axle-rotor protein assemblies

Natural molecular machines contain protein components that undergo motion relative to each other. Designing such mechanically constrained nanoscale protein architectures with internal degrees of freedom is an outstanding challenge for computational protein design. Here we explore the de novo construction of protein machinery from designed axle and rotor components with internal cyclic or dihedral symmetry. We find that the axle-rotor systems assemble in vitro and in vivo as designed. Using cryo-electron microscopy, we find that these systems populate conformationally variable relative orientations reflecting the symmetry of the coupled components and the computationally designed interface energy landscape. These mechanical systems with internal degrees of freedom are a step toward the design of genetically encodable nanomachines.

What is a covid dashboard?

 

Public Health Reporting has a long history (text here suddenly missing!)There is a long tradition of Public Health Reporting to support knowledge during public health crises. The Covid-19 pandemic has seen the unprecedented rapid demand for Public Health Reporting. The size, speed and scale of the pandemic led to governments, public health professionals, the media and citizens asking for up-to-date, accurate and accessible information and intelligence. One way that these demands were answered were through the creation and publication of Covid-19 dashboards to communicate to diverse audiences. Health Information Professionals were required to make significant decisions quickly. Which indicators to select? Which audiences to develop dashboards for? Which technologies to deploy? Decisions that would normally take a considerable length of time were abbreviated. There were no international standards and a variability of requirements for different commissioners of dashboards. Furthermore the public spotlight and ‘democratisation' of health information created additional pressure and a lack of situational control. Some of the choices made will have a consequential impact for shared Health Service and Population Health Research as the pandemic continues.

 

The purpose of this presentation is to

Discuss the need for rapid health reporting as a result of the Covid-19 pandemic

Examine some of the choices faced by health information professionals in creating and sustaining public Covid-19 dashboards during the pandemic.

Illustrate a variety of solutions that emerged internationally that were broadly trying to address the same need.

Standardized training in the rating of the six-item positive and negative syndrome scale (PANSS-6)

Introduction

The six-item Positive And Negative Syndrome Scale (PANSS-6) is short psychometric valid scale quantifying the severity of core schizophrenia symptoms. Using PANSS-6 to guide treatment decision-making requires that staff members’ ratings are valid and reliable.

Objectives

The objective of the study was to evaluate whether such valid and reliable PANSS-6 ratings can be obtained through a video-based training program.

Methods

One-hundred-and-four staff members from Aarhus University Hospital - Psychiatry, Denmark participated in the training. Participants conducted baseline PANSS-6 ratings based on a video of a patient being interviewed using the Simplified Positive And Negative Symptoms interview (SNAPSI). Subsequently, a theoretical introduction video was displayed followed by five SNAPSI patient interviews. After each SNAPSI video, individual ratings were performed before a video providing the gold standard scores was displayed. The validity of ratings was estimated by calculating the proportion of participants not deviating from the gold standard scores with >2 points on individual items or >6 points on the PANSS-6 total score. Reliability was evaluated after each step in the training by means of Gwet’s Agreement Coefficient (Gwet).

Results

By the end of the training, 72% of the participants rated within the acceptable deviations of the gold standard, ranging from 60% (nurses) to 91% (medical doctors/psychologists). The reliability improved (Gwet baseline vs. endpoint) for all PANSS-6 items, except for Blunted affect.

Conclusions

The majority of the staff members conducted valid PANSS-6 ratings after a brief standardized training program, supporting the implementation of PANSS-6 in clinical settings to facilitate measurement-based care.

Conflict of interest

Dr. Opler is a full-time employee of MedAvante-ProPhase Inc. Dr. Correll has been a consultant and/or advisor to or have received honoraria from: Acadia, Alkermes, Allergan, Angelini, Axsome, Gedeon Richter, Gerson Lehrman Group, Indivior, IntraCellular T

Left atrial function assessed by speckle tracking echocardiography predicts atrial fibrillation burden after catheter ablation independently of reconduction: a RACE-AF echocardiographic sub-study

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial (LA) function assessed by 2D speckle tracking echocardiography (STE) has demonstrated to be a useful predictor of recurrence of atrial fibrillation (AF) following catheter ablation (CA). Pulmonary vein reconduction (PVR) is one of the most important causes of recurrent paroxysmal AF (PAF) after ablation. The purpose of this study was to evaluate the association between AF burden (% of time in AF) following CA and LA strain measurements independently of PVR.

Methods

This prospective study included 66 patients with PAF who underwent CA (mean age 60 ± 8 years, 65% male). STE was performed during sinus rhythm prior to CA. AF burden was recorded by continuous rhythm monitoring using implantable loop recorders during a follow-up period of 4-6 months, excluding a blanking period of 3 months. After follow-up, all patients underwent an invasive assessment of pulmonary vein isolation to test for PVR. Multivariable linear regression analysis was used to assess the association between AF burden and peak atrial longitudinal reservoir strain (PALS), peak atrial contraction strain (PACS) and peak atrial conduit strain (PCS).

Results

Prior to CA, median AF burden was 3.8% (IQR: 0.5, 17). During follow-up, 37 patients (56%) were free of AF while median AF burden was 0.7% (IQR: 0.2, 1.6) in patients with an AF burden of more than 0%. A total of 35 patients (54%) were found to have PVR after ablation. Patients with AF recurrence had significantly lower PACS compared to patients with no AF during follow-up (10% ± 6% vs. 14% ± 5%, p = 0.004). No differences in PALS and PCS were observed. Increased PACS remained independently associated with low AF burden following CA after multivariable adjustments for clinical characteristics, comorbidities, and PVR (β=-0.262, p = 0.049) (Figure 1). PALS and PCS did not remain significantly associated with AF burden.

Conclusion

Increased PACS is strongly associated with low AF burden after CA even after adjusting for PVR. This suggests that an analysis of LA function could be useful to stratify patients prior to CA and improve treatment strategies.

Abstract Figure.

Serum angiotensin converting enzyme elevation in association with artificial stone silicosis

BACKGROUND

Silicosis is a rapidly emerging major health concern for workers in the artificial stone benchtop industry. The association between serum angiotensin converting enzyme (sACE) levels and artificial stone silicosis is unknown.

METHODS

We investigated 179 male workers (median age 40 years, interquartile range (IQR) 33-48 years) from the stone benchtop industry in Victoria, Australia. All had worked in an environment where dry processing of artificial stone had occurred and were registered with the Victorian Silica-associated Disease Registry between June 2019 and August 2020. Workers had undergone protocolised assessments including respiratory function testing, high resolution CT chest and blood tests panel, including sACE.

FINDINGS

Sixty workers with artificial stone silicosis were identified and they had a higher median sACE level (64.1 U/L, IQR 51.5, 87.5), compared to 119 without silicosis (35.0 U/L, IQR 25.0, 47.0). Compared to those with a normal assessment, regression modelling noted significantly higher average differences in sACE levels for workers with lymphadenopathy alone (12.1 U/L, 95% confidence interval (CI): 1.3, 22.9), simple silicosis (28.7 U/L, 95% CI: 21.3, 36.0) and complicated silicosis (36.0 U/L, 95% CI 25.2, 46.9). There was a small negative association with gas transfer, but no associations with exposure duration or spirometry.

CONCLUSION

sACE levels were noted to be higher in artificial stone workers with silicosis compared to those without disease and was highest in those with complicated silicosis. Longitudinal follow up is required to evaluate sACE as a prognostic biomarker for workers with this rapidly emerging occupational lung disease.

Factors Influencing Running Velocity at Lactate Threshold in Male and Female Runners at Different Levels of Performance

Background

The primary aim was to examine the relationship between lactate threshold (LT) expressed as percentage of maximal oxygen uptake (VO_2max) and running velocity at LT (LT_V). A secondary aim was to investigate to what extent VO_2max, oxygen cost of running (C_R), and maximal aerobic speed (MAS) determined LT_V. A third aim was to investigate potential differences in LT and LT_V between elite, national and recreational runners, as well as possible gender differences regarding VO_2max, C_R, LT, and LT_V.

Methods

Seventy-five competitive runners (37 males and 38 females) with an average VO_2max of 63.0 ± 9.3 mL⋅kg^–1⋅min^–1, and an average LT_V of 13.6 ± 2.3 km⋅h^–1 were tested for VO_2max, LT, LT_V, MAS, and C_R.

Results

Lactate threshold did not correlate with LT_V. With an r – value of 0.95 (p < 0.001) and a standard error of estimate of 4.0%, the product of MAS and individual LT determined 90% of LT_V, outside a range of ±0.27 km⋅h^–1. LT_V increased with higher performance level. However, LT did not differ between elite, national and recreational runners. Female runners had 2.5% higher LT, 8% lower LT_V, and 21% lower VO_2max, but 9% better C_R than male runners.

Conclusion

Lactate threshold did not correlate with LT_V. The product of MAS and LT correlated strongly with LT_V. There were no differences between elite, national and recreational runners regarding LT, but female runners had higher LT than the male runners. Female runners at the same relative performance level had lower LT_V and VO_2max, but better C_R than male runners.

Genome-wide association study of patients with atrioventricular nodal reentry tachycardia

Background

Supraventricular tachycardias (SVTs) originate from the atria or the area close to the AV node. AV nodal reentry tachycardia (AVNRT) is one of the tachyarrhytmias comprising the group of SVTs. The typical patient is female, young at disease onset, with a structurally normal heart. At present we do not know the etiology of AVNRT. We therefore hypothesized that AVNRT might be caused by changes in the DNA.

Methods

DNA from purified blood was obtained from patients with AVNRT verified by an invasive electrophysiological study. Patients were recruited from five ablation centers in Denmark and individuals from the general population of Denmark (the BEFUS cohort) served as controls. DNA was subjected to chip genotyping, imputation and analyses in a genome-wide association study (GWAS) setup.

Results

A GWAS on 1,143 AVNRT patients and 3,004 controls revealed one locus close to the gene MYH6 to reach genome-wide significance for association with AVNRT (P=4.8x10–8). MYH6 encodes the α-isoform of the protein myosin heavy chain important for the contractile units of the heart, the sarcomeres. The gene is predominantly expressed in the atria. Additional subthreshold loci located close to other plausible arrhythmia genes were identified.

Conclusion

We report the first genetic locus to be associated with AVNRT close to the sarcomere gene MYH6. This is, to our knowledge, the first gene ever associated with AVNRT.

Manhattan plot

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Rigshospitalets Forskningspulje - 3 years PhD salary

Relationship between cardiac structure and function and atrial fibrillation related hospitalizations following catheter ablation

Background

Even though catheter ablation (CA) is an effective treatment for atrial fibrillation (AF), AF-related hospitalizations and cardioversions are common following this procedure.

Purpose

To investigate whether echocardiographic measures of left atrial (LA) function could predict AF-related hospitalizations and cardioversions.

Methods

This was a substudy of a trial that randomized patients to amiodarone vs place to reduce AF recurrence following CA. Transthoracic echocardiography was performed prior to CA and included assessment of: end-systolic and end-diastolic LA volumes, emptying fraction (LAEF), atrial strain, and global longitudinal strain (GLS). Poisson regression was used to assess predictive value for AF-related hospitalizations and cardioversions. Multivariable adjustments were made for: age, gender, ejection fraction, AF burden, AF subtype, dyspnea, and class 1c antiarrhythmics.

Results

Of the 212 patients, 80 were hospitalized for AF (206 times), and 77 were cardioverted (192 times) within the 6 months follow-up period. Mean age was 60 years, 83% were men, and mean LVEF was 50%. In univariable analyses, LA volumes, LAEF and GLS were predictors of the outcomes but did not remain significant predictors after multivariable adjustments. During echocardiography 162 patients were in sinus rhythm and 50 had AF rhythm. Rhythm during the echocardiogram modified the association between GLS and outcomes (p for interaction &lt;0.05 for both endpoints), such that GLS predicted both AF-related hospitalizations and cardioversions in patients with sinus rhythm but not AF during the echocardiogram (figure).

Conclusion

Global longitudinal strain predicts AF-related hospitalizations and cardioversions after CA, but only in patients presenting in sinus rhythm during the echocardiogram. Patients presenting with impaired global longitudinal strain should be considered high-risk patients following CA who may benefit from close follow-up.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Danish Heart Foundation

Treatment protocol for secondary esophageal reconstruction using 'supercharged' colon interposition flaps

Locoregional esophageal cancer is currently treated with induction chemoradiotherapy, followed by esophagectomy with reconstruction, using a gastric conduit. In cases of conduit failure, patients are temporized with a cervical esophagostomy and enteral nutrition until gastrointestinal continuity can be established. At our institution, we favor reconstruction, using a colon interposition with a 'supercharged' accessory vascular pedicle. Consequently, we sought to examine our technique and outcomes for esophageal reconstruction, using this approach. We performed a retrospective review of all patients who underwent esophagectomy at our center between 2008 and 2018. We identified those patients who had a failed gastric conduit and underwent secondary reconstruction. Patient demographics, perioperative details, and clinical outcomes were analyzed after our clinical care pathway was used to manage and prepare patients for a second major reconstructive surgery. Three hundred and eighty eight patients underwent esophagectomy and reconstruction with a gastric conduit. Seven patients (1.8%) suffered gastric conduit loss and underwent a secondary reconstruction using a colon interposition with a 'supercharged' vascular pedicle. Mean age was 70.1 (±7.3) years, and six patients were male. The transverse colon was used in four cases (57.1%), left colon in two cases (28.6%), and right colon in one case (14.3%). There were no deaths or loss of the colon interposition at follow-up. Three patients (42.9%) developed an anastomotic leak, which resolved with conservative management. All patients had resumption of oral intake within 30 days. Utilizing a 'supercharging' technique for colon interposition may improve the perfusion to the organ and may decrease morbidity. Secondary reconstruction should occur when the patient's oncologic, physiologic, and psychosocial condition is optimized. Our outcomes and preoperative strategies may provide guidance for those centers treating this complicated patient population.

LB0002 A FIRST IN CLASS THERAPEUTIC NANOPARTICLE FOR SPECIFIC TARGETING OF ANTI-CITRULLINATED PROTEIN ANTIBODY AMELIORATES SERUM TRANSFER AND COLLAGEN INDUCED ARTHRITIS

Background:

Rheumatoid arthritis (RA) is an immune mediated inflammatory disease with autoimmune features, including antibodies to citrullinated proteins and peptides (ACPAs). Several in vitro studies have suggested a pathogenic role of ACPAs in RA. However, in vivo proof of this concept has been hampered by the lack of therapeutic strategies to reduce or deplete ACPA in serum and synovial fluid. Previously, we constructed a chitosan-hyaluronic acid nanoparticle formulation with the ability to use neutrophil recruitment as a delivery mechanism to inflamed joints. Specifically, nanoparticles got phagocytosed and then released to synovial fluid upon death of the short-lived neutrophils

Objectives:

We hypothesized that reducing ACPA levels would have a therapeutic effect by blocking cytokine production. In this study, we prepared and tested a series of therapeutic nanoparticles for specific targeting of ACPA in synovial fluid.

Methods:

Nanoparticles were prepared by the microdroplet method and then decorated with synthetic cyclic citrullinated peptide aptamer PEP2, PEG/hexanoic acid and fluorophore (Cy5.5). Nanoparticles were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM) and high-performance liquid chromatography (HPLC). Nanoparticles were then used in a series of in vitro assays, including cell uptake with flow cytometry (FACS) detection, and in vivo studies including disease activity scores, cytokine measurements and near-infrared imaging.

Results:

We screened a series of citrullinated peptide epitopes and identified a fibrinogen-derived 21-amino-acid-long citrullinated peptide showing high selectivity toward autoantibodies in RA samples. We incorporated this aptamer in the chitosan-hyaluronic acid nanoparticle formulation previously described. Average nanoparticle size was 230 nm ± 10 nm by DLS and SEM; z potential was -0.0012. Purity by HPLC was over 95%. Attachment efficiency of the aptamer was 92% by HPLC. FACS study showed selective uptake of Cy5.5 labelled aptamer-nanoparticle conjugates by neutrophils in the concentration range 0.5-4 nM. Similar to previous studies,1there was no apparent immunogenicity for this nanoparticle formulation measured by cytokine secretion from human peripheral blood leukocytes. In vivo, over 50% reduction of disease activity was achieved in three weeks treatment using as little as 1 nM drug candidate (dosed every 48 hours) in the collagen-induced (CIA) mouse model of RA (N=30; p<0.001 for treated vs placebo). Same was observed in the serum transfer model (N=10). The aptamer-nanoparticle conjugate significantly reduced IL-6 and TNFα levels in the mouse sera (p<0.01). The effects were not inferior to tocilizumab treated controls (N=30). To confirm mode of action, we applied Cy5.5-labelled aptamer-nanoparticles in the collagen-induced mouse model (N=10) and analyzed the resulting uptake by near-infrared imaging. We confirmed over 6-fold higher signal accumulation in inflamed vs healthy joints (p<0.01), which strongly supports the fact that the aptamer is highly specific to the inflammatory process.

Conclusion:

Overall, we have designed a first-in-class therapeutic nanoparticle drug for specific targeting of anti-citrullinated protein antibodies. The marked effect of this nanoparticle observed in vivo holds promise for targeting ACPAs as a therapeutic option in RA.

References:

[1]Khatri S, Hansen J, Mendes AC, Chronakis IS, Hung S-C, Mellins ED, Astakhova K. Bioconjug Chem. 2019 Oct 16;30(10):2584–259

Disclosure of Interests:

Sangita Khatri: None declared, Jonas Hansen: None declared, Mads Hartvig Clausen Shareholder of: iBio Tech ApS, Tue Wenzel Kragstrup Shareholder of: iBio Tech ApS, Consultant of: Bristol-Myers Squibb, Speakers bureau: TWK has engaged in educational activities talking about immunology in rheumatic diseases receiving speaking fees from Pfizer, Bristol-Myers Squibb, Eli Lilly, Novartis, and UCB., Shu-Chen Hung: None declared, Elisabeth Mellins: None declared, Kira Astakhova: None declared

Increasing Oxygen Uptake in Well-Trained Cross-Country Skiers During Work Intervals With a Fast Start

PURPOSE

Accumulated time at a high percentage of peak oxygen consumption (VO2peak) is important for improving performance in endurance athletes. The present study compared the acute effect of a roller-ski skating session containing work intervals with a fast start followed by decreasing speed (DEC) with a traditional session where the work intervals had a constant speed (similar to the mean speed of DEC; TRAD) on physiological responses, rating of perceived exertion, and leg press peak power.

METHODS

A total of 11 well-trained cross-country skiers performed DEC and TRAD in a randomized order (5 × 5-min work intervals, 3-min relief). Each 5-minute work interval in the DEC protocol started with 1.5 minutes at 100% of maximal aerobic speed followed by 3.5 minutes at 85% of maximal aerobic speed, whereas the TRAD protocol had a constant speed at 90% of maximal aerobic speed.

RESULTS

DEC induced a higher VO2 than TRAD, measured as both peak and average of all work intervals during the session (98.2% [2.1%] vs 95.4% [3.1%] VO2peak, respectively, and 87.6% [1.9%] vs 86.1% [3.2%] VO2peak, respectively) with a lower mean rating of perceived exertion after DEC than TRAD (16.1 [1.0] vs 16.5 [0.7], respectively) (all P < .05). There were no differences between sessions for mean heart rate, blood lactate concentration, or leg press peak power.

CONCLUSION

DEC induced a higher mean VO2 and a lower rating of perceived exertion than TRAD, despite similar mean speed, indicating that DEC can be a good strategy for interval sessions aiming to accumulate more time at a high percentage of VO2peak.

Superior performance improvements in elite cyclists following short-interval vs effort-matched long-interval training

The purpose of this study was to compare the effects of 3 weeks with three weekly sessions (ie, nine sessions in total) of short intervals (SI; n = 9; 3 series with 13 × 30-second work intervals interspersed with 15-second recovery and 3-minutes recovery between series) against effort-matched (rate of perceived effort based) long intervals (LI; n = 9; 4 series of 5-minute work intervals with 2.5-minutes recovery between series) on performance parameters in elite cyclists ( V ˙ O 2max 73 ± 4 mL min^-1  kg^-1 ). There were no differences between groups in total volume and intensity distribution of training during the intervention period. SI achieved a larger (P < .05) relative improvement in peak aerobic power output than LI (3.7 ± 4.3% vs -0.3 ± 2.8%, respectively), fractional utilization of V ˙ O 2max at 4 mmol L^-1 [La^- ] (3.0 ± 5.8 percent points vs -3.5 ± 2.7 percent points, respectively), and larger relative increase in power output at 4 mmol L^-1 [La^- ] (2.0 ± 6.7% vs -2.8 ± 3.4, respectively), while there was no group difference in change of V ˙ O 2max . Improvements in performance measured as mean power output during 20-minute cycling test were greater (P < .01) in SI compared with LI (4.7 ± 4.4% vs -1.4 ± 2.2%, respectively). Mean effect size of the improvement in the above variables revealed a small to large effect of SI training vs LI training. The data thus demonstrate that the present SI protocol induces superior training adaptations compared with the present LI protocol in elite cyclists.

Influence of Postmortem Aging and Storage Conditions on Tenderness of Grain and Grass Finished Bison Striploin Steaks

ObjectivesThe objectives of this study were to: 1) compare the influence of postmortem aging on tenderness of striploin steaks from grain- and grass-finished bison, and 2) compare the influence of freezing on tenderness of striploin steaks from grain- and grass-finished bison.Materials and MethodsBison heifers were randomly assigned to finishing treatments: Grain-finished (n = 30, backgrounded on pasture and finished for 130 d with ad libitum access to grass hay, alfalfa and a corn and dry distiller’s grain concentrate prior to slaughter) or Grass-finished (n = 30, remained on pasture until slaughter). Heifers were slaughtered at approximately 28 mo of age, and striploins were removed from both sides of the carcass posterior to the 12th rib separation and fabricated into 2.54-cm steaks. One steak was removed from each striploin (n = 60), vacuum packaged and stored fresh for 14 d at 4°C. Four additional steaks were fabricated from each striploin, aged for 4,7,14, or 21 d, vacuum packaged, and frozen for approximately 3 mo. Warner-Bratzler Shear Force (WBSF) was utilized to determine objective tenderness. Frozen steaks were thawed at 4°C for 24 h before cooking. All steaks were weighed prior to cooking to an internal temperature of 71°C. Internal temperature was monitored using a digital thermometer placed near the geometric center of each steak. After cooking, all steaks were reweighed to determine cook loss and cooled to room temperature (20°C). Five to six 1.27-cm cores were removed from each steak and sheared once perpendicular to the muscle fiber orientation and peak force was recorded. A texture analyzer with a Warner-Bratzler attachment was used to assess instrumental tenderness. An average shear force value was then calculated for each steak. For Objective 1, cook loss and shear force data were analyzed as repeated measures using the ante-dependence covariance structure in the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) for effects of finishing treatment, aging, and their interaction; peak temperature was included as a covariate. For Objective 2, shear force data were analyzed for the effects of finishing treatment, storage treatment and their interaction using the GLM procedure of SAS. For both objectives, the interaction was not significant and omitted from the final model. Separation of least-squares main effect means was performed using LSD with a Tukey’s adjustment and assuming a level of 0.05.ResultsSteaks from grain finished bison heifers had tendency to be more tender (P = 0.0552) and had less cook loss (P < 0.0001) than steaks from grass finished heifers. Tenderness of all steaks improved (P < 0.0001) with postmortem aging. Aging time also influenced cook loss (P = 0.0199). Cook loss was greater (P = 0.0133) at Day 4 than Day 7 and tended to be greater (P = 0.0561) at Day 4 than Day 21. Frozen storage improved tenderness (P < 0.0001) and increased cook loss (P < 0.0001) of bison steaks compared to fresh storage.ConclusionCollectively this data indicates postmortem aging, storage conditions, and finishing systems influence meat tenderness of bison striploin steaks. Grain-finishing resulted in reduced cook loss and tended to improved tenderness of bison steaks compared to grass-finishing. Additionally, holding bison steaks in frozen storage improved tenderness, but also increased cook loss.

[E-Cigarette Use and Later Use of Conventional Cigarettes - Results of a Prospective Observational Study over 2 Years]

AIM

 The aim was to investigate whether e-cigarette use predicts later experimentation with conventional cigarettes.

METHODS

 During the 2016/2017 school year, 2,388 children and adolescents from Baden-Württemberg, Mecklenburg-Western Pomerania, North Rhine-Westphalia, Rhineland-Palatinate, Schleswig-Holstein and Saxony who had never smoked conventional cigarettes before took part in a survey over a 2-year period (mean age 11.8 years, SD = 1.21; 49.6 % female).

RESULTS

 At baseline, 85 pupils (3.6 %) reported that they had already tried e-cigarettes at least once. By the end of the observational period, 430 of the sample had tried conventional cigarettes (18.0 %). After statistical control for age, sex, migration background, type of school, socioeconomic status, sensation-seeking, alcohol use, and school performance, the adjusted relative risk of experimentation with conventional cigarettes was 85 % higher (adjusted relative risk = 1.85, 95 % CI [1.34 - 2.56]) for pupils who had used e-cigarettes at baseline. Further analyses revealed that the risk was higher among adolescents with low sensation-seeking scores.

CONCLUSION

 Among young never-smokers, experimentation with conventional cigarettes is more common in those who used e-cigarettes before than among those who have not tried e-cigarettes before. This effect seems to be stronger among adolescents who, in general, have a lower risk of starting to smoke.

Why do we need for timeliness of research in decision-making?

Background

Compared to the policy process, the research process is slow. As a result, research evidence is not always available when needed in the policy process. These differences in timelines between research and policy hinder the use of research evidence in the policy process. In order to support evidence-based policy making, timeliness of research is important.

Methods

Examples are provided, e.g. where research was on time to be included in the policy process and where research was too late to be included in it. These examples are described and analysed to provide for recommendations on how to better align both processes.

Results

It is shown that in order to create timeliness of research, policy makers and researchers should talk on a regular basis. This increases the chance that results from the research are included in policy making.

Conclusions

Timeliness of research is important for evidence-based policy making. In order to create timeliness of research, interaction between researchers and policy makers is important.

Regional shortages in a small country: how to provide the right care in the right place?

Background

The Netherlands, though being a relatively small and densely populated country, is faced with a similar challenge as other countries in terms of regional differences in access to care and attractiveness for care workers to build their careers. Both in primary care and hospital care new solutions are being sought which should help resolve these growing difficulties.

Methods

We conducted a literature review, survey and registry analysis, and held interviews with key stakeholders.

Results

Substantial differences exist between regions in the supply of both primary care and hospital care doctors. Particular and less populated regions appear to be hit in multiple ways, both with an extra ageing population requiring more care as well as by limited attractiveness for both primary care and hospital care workers. Solutions being used so far are mostly initiated by individual health care settings, such as strategic personnel management, redistribution of tasks and campaigns to increase the inflow of staff. Increasingly, solutions are also being explored at regional level, including a growing emphasis on regional collaboration, both in providing the right care in the right place as well as in terms of joint recruitment strategies. Still, such approaches only have a limited effect as a result of which new approaches are needed.

Conclusions

Strategies to improve the attractiveness of particular regions are now often fragmented, both between types of professions and sectors and different regions. In addition, innovative and new solutions appear to be hampered by vested interests of stakeholders. If new solutions are to be developed it is key that stakeholders are willing to compromise, be it when it comes to the autonomy of health care professionals and their associations and to the financial commitments required from government and insurer side.

Deleting Suppressor of Cytokine Signaling-3 in chondrocytes reduces bone growth by disrupting mitogen-activated protein kinase signaling

OBJECTIVE

To investigate the impact of deleting Suppressor of Cytokine Signaling (SOCS)-3 (SOCS3) in chondrocytes during murine skeletal development.

METHOD

Mice with a conditional Socs3 allele (Socs3^fl/fl) were crossed with a transgenic mouse expressing Cre recombinase under the control of the type II collagen promoter (Col2a1) to generate Socs3^Δ/Δcol2 mice. Skeletal growth was analyzed over the lifespan of Socs3^Δ/Δcol2 mice and controls by detailed histomorphology. Bone size and cortical bone development was evaluated by micro-computed tomography (micro-CT). Growth plate (GP) zone width, chondrocyte proliferation and apoptosis were assessed by immunofluorescence staining for Ki67 and TUNEL. Fibroblast growth factor receptor-3 (FGFR3) signaling in the GP was assessed by immunohistochemistry, while the effect of SOCS3 overexpression on FGFR3-driven pMAPK signaling in HEK293T cells was evaluated by Western blot.

RESULTS

Socs3^Δ/Δcol2 mice of both sexes were consistently smaller compared to littermate controls throughout life. This phenotype was due to reduced long bone size, poor cortical bone development, reduced Ki67⁺ proliferative chondrocytes and decreased proliferative zone (PZ) width in the GP. Expression of pMAPK, but not pSTAT3, was increased in the GPs of Socs3^Δ/Δcol2 mice relative to littermate controls. Overexpression of FGFR3 in HEK293T cells increased Fibroblast Growth Factor 18 (FGF18)-dependent Mitogen-activated protein kinase (MAPK) phosphorylation, while concomitant expression of SOCS3 reduced FGFR3 expression and abrogated MAPK signaling.

CONCLUSION

Our results suggest a potential role for SOCS3 in GP chondrocyte proliferation by regulating FGFR3-dependent MAPK signaling in response to FGF18.

P2247Pregnancies and childbirth in women with arrhythmogenic right ventricular cardiomyopathy are associated with low risk of ventricular arrhythmias

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with a risk of ventricular arrhythmias (VA) and sudden cardiac death (SCD). Even though female patients with ARVC are considered to be at lower risk of VA, the impact of pregnancy and child birth on the arrhythmic risk and development of arrhythmic substrate in the context of ARVC remains insufficiently studied.

Objective

To assess the risk of VA in relation to childbirth in women with ARVC and the impact of multiple pregnancies on progression of arrhythmic manifestations of the disease.

Methods

The study included 186 females with definite ARVC (n=107, 70 probands) or unaffected mutation-carriers (n=79) with median age at the end of follow up of 48 (IQR 34–60) years. Seventeen women had 1, 59 had 2 and 29 had ≥3 child births by the age of 40 years. VA was defined as ventricular tachycardia, appropriate ICD therapy, aborted cardiac arrest or SCD. Proportions of patients who experienced VA by the age of 40 years were compared between nulliparous women (n=81) and those with reported child births (n=105). VA-free survival after accomplished pregnancies was assessed for women ≥40 years of age (n=119). Cumulative probability of VA for each pregnancy (n=230) was assessed from conception through 2 years after child birth and compared between those that occurred before ARVC diagnosis (Pre-Ds, n=164), after it (Post-Ds, n=11) and in unaffected mutation carriers (No-Ds, n=55).

Results

The nulliparous women had lower age at ARVC diagnosis (37 vs 44, p=0.023) and more often had VA before the age of 40 (31% vs 13%, p=0.003) while the number of child births was not related to the prevalence of VA (18% among women with 1 childbirth, 12% in those with 2 and 14% in those with 3 or more, ns). Three women suffered SCD before the age of 40. VA-free survival after 40 years did not differ between nulliparous and those who gave birth (Figure A). Only four pregnancy-related events were documented (Figure B): 1 in the Post-Ds group and three in the Pre-Ds group. No pregnancy-related events were reported in the unaffected mutation carriers.

Conclusion

In this Scandinavian cohort of women with ARVC we observed no indication of an increased VA risk either associated with pregnancies or during long-term follow up after the last child birth.

P992Incidence, predictors, and success of ventricular tachycardia catheter ablation in arrhythmogenic right ventricular cardiomyopathy (ARVC): A long-term cohort study from the Nordic ARVC registry

Background

Catheter ablation may reduce ventricular tachycardia (VT) burden in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. However, little is known about factors predicting need for ablation and various outcomes have been reported.

Purpose

We sought to investigate predictors and use of VT ablation and to evaluate the post-procedural outcome in ARVC patients.

Methods

We studied 435 patients from the Nordic ARVC registry including 220 probands with definite ARVC according to the 2010 task force criteria and 215 mutation-carrying relatives identified through cascade screening. Patients were followed until first-time VT ablation, death, heart transplantation, or January 1st 2018. Additionally, patients undergoing VT ablation were further followed from the time of ablation for recurrent ventricular arrhythmias.

Results

Cumulative use of VT ablation was 4% (95% CI 3%-6%) and 11% (95% CI 8%-15%) after 1 and 10 years. All procedures were performed in probands in whom the cumulative use was 8% (95% CI 5%-12%) and 20% (95% CI 15%-26%). In adjusted analyses restricted to probands, only young age predicted need for ablation. In patients undergoing ablation, risk of recurrent arrhythmias was 59% (95% CI 44%-71%) and 74% (95% CI 59%-84%) 1 and 5 years after the procedure. Despite high recurrence rates, the burden of ventricular arrhythmias was reduced after ablation (p=0.0042). Young age, use of several antiarrhythmic drugs and inducibility to VT immediately after ablation were associated with an unfavorable outcome.

Conclusions

Twenty percent of ARVC probands developed a clinical indication for VT ablation within 10 years after diagnosis whereas mutation-carrying relatives were without such need. Although the burden of ventricular arrhythmias decreased after ablation, risk of recurrence was substantial.

Large-scale determination of micropollutant elimination from municipal wastewater by passive sampling gives new insights in governing parameters and degradation patterns

A simple balancing method using passive samplers over a week's period has been developed and tested successfully to determine elimination rates of 22 common micropollutants of household and industrial sources in 18 full-scale wastewater treatment plants of different design and performance. Independent reactor tests to delineate elimination rates with native sludge of the treatment plants correlated very well with the full-scale elimination rate determinations. As opposed to common assumptions, this large dataset indicated that shorter sludge retention times - read: higher active biomass - showed higher micropollutant elimination rates in many cases. Multivariate statistical analysis of the elimination rates over the 18 treatment plants was able to group compounds according to common degradation pathways and showed that sensitivity to SRT drove the grouping. The dataset also allowed to determine population equivalent normalized loads of the investigated micropollutants. The application of WWTP balancing with passive sampling makes it relatively easy to gather elimination rates and inlet loads on a much broader basis than before and gives orientation for more in-depth analysis of degradation pathways.

Case Studies in Physiology: Temporal changes in determinants of aerobic performance in individual going from alpine skier to world junior champion time trial cyclist

This paper reports temporal changes in physiological measurements of exercise performance in a young man transitioning from alpine skiing until he became a world junior champion time trial cyclist after only 3 yr of bike-specific training. At the time he became World Champion he also achieved among the highest reported maximal oxygen uptake (V̇o_2max) value, 96.7 ml·min^-1·kg^-1, or 7,397 ml/min in absolute terms at 76.5 kg, which had increased by 29.6% from 74.6 ml·min^-1·kg^-1 pre-bike-specific training. After 15 mo with almost no structured exercise training, V̇o_2max returned to 77.0 mL·min^-1·kg^-1 and was similar to the value reported before specific bike training, albeit with absolute term (6,205 ml/min) still being 11.3% higher. Part of the explanation for his athletic achievements is likely also related to the up to 20.9% improvement in Power@4 mmol/l (W). Although genetic profiles of endurance athletes have not generated data suggesting a shared genetic signature associated with elite endurance performance, this case study highlights the importance of intrinsic biological factors in elite endurance performance.NEW & NOTEWORTHY This study shows that very high V̇o_2max values (>70 ml·min^-1·kg^-1) can be found in individuals not previously specializing in aerobic training and that values of >90 ml·min^-1·kg^-1, as well as a cycling world junior champion title, can be achieved in such individuals with just 3 yr of dedicated exercise training.

Experimental Observation of Proton Bunch Modulation in a Plasma at Varying Plasma Densities

We give direct experimental evidence for the observation of the full transverse self-modulation of a long, relativistic proton bunch propagating through a dense plasma. The bunch exits the plasma with a periodic density modulation resulting from radial wakefield effects. We show that the modulation is seeded by a relativistic ionization front created using an intense laser pulse copropagating with the proton bunch. The modulation extends over the length of the proton bunch following the seed point. By varying the plasma density over one order of magnitude, we show that the modulation frequency scales with the expected dependence on the plasma density, i.e., it is equal to the plasma frequency, as expected from theory.

Experimental Observation of Plasma Wakefield Growth Driven by the Seeded Self-Modulation of a Proton Bunch

We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of 2.1×10^{14} and 7.7×10^{14}  electrons/cm^{3}. We show that these wakefields periodically defocus the proton bunch itself, consistently with the development of the seeded self-modulation process. We show that the defocusing increases both along the bunch and along the plasma by using time resolved and time-integrated measurements of the proton bunch transverse distribution. We evaluate the transverse wakefield amplitudes and show that they exceed their seed value (<15  MV/m) and reach over 300  MV/m. All these results confirm the development of the seeded self-modulation process, a necessary condition for external injection of low energy and acceleration of electrons to multi-GeV energy levels.