Serum neurofilament level increases after ascent to 4559 m but is not related to acute mountain sickness.

BACKGROUND AND PURPOSE: At high altitude the brain is exposed to hypoxic stress, which may result in neurological conditions, with acute mountain sickness (AMS) being the most common. We aimed to test the hypothesis that rapid ascent to high altitude alters neuro-axonal integrity, which can be detected by increased concentration of serum neurofilament light (sNfL) in the blood and may even be exaggerated in people with AMS. METHODS: Serum neurofilament light was measured using a single-molecule array (Simoa, Quanterix, Lexington, MA, USA) assay at low altitude (423 m) in 47 healthy study participants and 44 h after rapid and active ascent to high altitude (4559 m). Peripheral oxygen saturation (SpO2 ) and partial pressures of oxygen (pO2 ) were obtained at low and high altitude. The Acute Mountain Sickness-Cerebral (AMS-C) scoring system was used to assess AMS incidence and AMS severity. RESULTS: There was an increase in sNfL from its baseline value compared with its value at high altitude (6.34 ± 1.96 vs. 7.19 ± 3.14 pg/ml; p = 0.014), but sNfL level did not correlate with SpO2 (r = -0.19; p = 0.066) or pO2 (r = -0.19; p = 0.068). The incidence of AMS at high altitude was 62%. Neither at low altitude (p = 0.706) nor at high altitude (p = 0.985) was there a difference in sNfL between participants with and without AMS as measured 3 days after rapid ascent and 44 h of high-altitude exposure. Altitude sNfL did not correlate with AMS-C, either overall or with single-item scores such as headache severity. CONCLUSIONS: Rapid ascent of healthy people to high altitude provokes an increase in sNfL 44 h after arrival at 4559 m, which is not related to the magnitude of hypoxemia or AMS incidence and severity, suggesting that neuro-axonal injury does not directly contribute to AMS.

Validity of Peripheral Oxygen Saturation Measurements with the Garmin Fenix® 5X Plus Wearable Device at 4559 m.

Decreased oxygen saturation (SO2) at high altitude is associated with potentially life-threatening diseases, e.g., high-altitude pulmonary edema. Wearable devices that allow continuous monitoring of peripheral oxygen saturation (SpO2), such as the Garmin Fenix® 5X Plus (GAR), might provide early detection to prevent hypoxia-induced diseases. We therefore aimed to validate GAR-derived SpO2 readings at 4559 m. SpO2 was measured with GAR and the medically certified Covidien Nellcor SpO2 monitor (COV) at six time points in 13 healthy lowlanders after a rapid ascent from 1130 m to 4559 m. Arterial blood gas (ABG) analysis served as the criterion measure and was conducted at four of the six time points with the Radiometer ABL 90 Flex. Validity was assessed by intraclass correlation coefficients (ICCs), mean absolute percentage error (MAPE), and Bland-Altman plots. Mean (±SD) SO2, including all time points at 4559 m, was 85.2 ± 6.2% with GAR, 81.0 ± 9.4% with COV, and 75.0 ± 9.5% with ABG. Validity of GAR was low, as indicated by the ICC (0.549), the MAPE (9.77%), the mean SO2 difference (7.0%), and the wide limits of agreement (-6.5; 20.5%) vs. ABG. Validity of COV was good, as indicated by the ICC (0.883), the MAPE (6.15%), and the mean SO2 difference (0.1%) vs. ABG. The GAR device demonstrated poor validity and cannot be recommended for monitoring SpO2 at high altitude.

Effects of active commuting to work for 12 months on cardiovascular risk factors and body composition.

Active commuting has the potential to decrease cardiovascular risk by increasing physical activity. We aimed to investigate the effects of active commuting to work for 12 months on body composition and cardiovascular risk factors. Therefore, 73 hospital employees (age: 46 ± 9 years, 36% males), with a predominantly passive way of commuting, were randomly assigned to an intervention group (IG) and a control group (CG) in a 2:1 fashion. The IG was further divided into a public transportation plus active commuting group (IG-PT) and a cycling group (IG-C). Both IGs were prompted to reach 150 min/wk of moderate intensity exercise. Daily self-reported commuting details were verified by GPS tracking. All subjects underwent assessment of body composition, resting blood pressure, glycemic control, and lipid profile at the beginning and end of the study. Data for final analyses were available in 62 subjects. Commuting details indicated that the subjects randomized to IG changed their commuting habits. HbA1c decreased by 0.2% [95%CI: -0.3, -0.2] in IG-PT but was not statistically different between groups (P = .06). LDL cholesterol decreased in IG-C by 0.8 mmol/L [-1.1, -0.4] and by 0.6 mmol/L [-1.2, 0.1] in IG-PT which can be considered biologically relevant but did not yield statistical significance. Body composition and blood pressure did not differ between groups. Active commuting to work for 12 months did not change body composition but yielded relevant changes in lipid profile and glycemic control. Health benefits of active commuting should be addressed by healthcare professionals when counseling individuals that seek to improve their cardiovascular risk profile.

Mobile Technologies to Promote Physical Activity during Cardiac Rehabilitation: A Scoping Review.

Promoting regular physical activity (PA) and improving exercise capacity are the primary goals of cardiac rehabilitation (CR). Mobile technologies (mTechs) like smartphones, smartwatches, and fitness trackers might help patients in reaching these goals. This review aimed to scope current scientific literature on mTechs in CR to assess the impact on patients' exercise capacity and to identify gaps and future directions for research. PubMed, CENTRAL, and CDSR were systematically searched for randomized controlled trials (RCTs). These RCTs had to utilize mTechs to objectively monitor and promote PA of patients during or following CR, aim at improvements in exercise capacity, and be published between December 2014 and December 2019. A total of 964 publications were identified, and 13 studies met all inclusion criteria. Home-based CR with mTechs vs. outpatient CR without mTechs and outpatient CR with mTechs vs. outpatient CR without mTechs did not lead to statistically significant differences in exercise capacity. In contrast, outpatient CR followed by home-based CR with mTechs led to significant improvement in exercise capacity as compared to outpatient CR without further formal CR. Supplying patients with mTechs may improve exercise capacity. To ensure that usage of and compliance with mTechs is optimal, a concentrated effort of CR staff has to be achieved. The COVID-19 pandemic has led to an unprecedented lack of patient support while away from institutional CR. Even though mTechs lend themselves as suitable assistants, evidence is lacking that they can fill this gap.

Impairment of left atrial mechanics does not contribute to the reduction in stroke volume after active ascent to 4559 m.

Hypoxia challenges left ventricular (LV) function due to reduced energy supply. Conflicting results exist whether high-altitude exposure impairs LV diastolic function and thus contributes to the high altitude-induced increase in systolic pulmonary artery pressure (sPAP) and reduction in stroke volume (SV). This study aimed to assess LV diastolic function, LV end-diastolic pressure (LVEDP), and LA mechanics using comprehensive echocardiographic imaging in healthy volunteers at 4559 m. Fifty subjects performed rapid (<20 hours) and active ascent from 1130 m to 4559 m (high). All participants underwent echocardiography during baseline examination at 424 m (low) as well as 7, 20 and 44 hours after arrival at high altitude. Heart rate (HR), sPAP, and comprehensive volumetric- and Doppler- as well as speckle tracking-derived LA strain parameters were obtained to assess LV diastolic function, LA mechanics, and LVEDP in a multiparametric approach. Data for final analyses were available in 46 subjects. HR (low: 64 ± 11 vs high: 79 ± 14 beats/min, P < 0.001) and sPAP (low: 24.4 ± 3.8 vs high: 38.5 ± 8.2 mm Hg, P < 0.001) increased following ascent and remained elevated at high altitude. Stroke volume (low: 64.5 ± 15.0 vs high: 58.1 ± 16.4 mL, P < 0.001) and EDV decreased following ascent and remained decreased at high altitude due to decreased LV passive filling volume, whereas LA mechanics were preserved. There was no case of LV diastolic dysfunction or increased LVEDP estimates. In summary, this study shows that rapid and active ascent of healthy individuals to 4559 m impairs passive filling and SV of the LV. These alterations were not related to changes in LV and LA mechanics.

Preserved Left Atrial Mechanics Following a 5-h Laboratory Triathlon in Euhydrated Athletes.

The purpose of this study was to investigate echocardiographic changes in left ventricular (LV) diastolic filling and left atrial (LA) strain mechanics following prolonged exercise. Ten male triathletes completed a 60-min swim, 180-min bike exercise, and a 60-min all-out run in a laboratory environment. Special attention was paid to prevent dehydration and energy deficit during the exercise protocol. All participants underwent comprehensive echocardiographic analyses of Doppler- and volumetric-derived LV diastolic filling indices and novel speckle-tracking echocardiography (STE)-derived LA strain indices. LV stroke volume (pre: 108.0±15.9 vs. post: 88.8±19.0 mL; p=0.03) and LA passive emptying volume (pre: 31.2±7.5 vs. post: 22.4±9.8 mL; p=0.05) were significantly reduced following the exercise protocol. Of the STE-derived indices of LA function, reservoir and conduit strain did not change significantly, while there was a trend towards enhanced contraction strain (pre: 15.1±3.8 vs. post: 19.4±4.8%; p=0.07). Resting heart rate was significantly higher post-exercise (53.1±5.0 vs. 81.9±16.9 bpm; p<0.001) and its change correlated strongly with depression of Doppler-derived ratio of early to late ventricular filling velocities (r=0.74, p=0.01) and reduction of LA passive emptying volume (r=0.86, p=0.01). Following prolonged exercise, LV stroke volume was reduced due to heart rate related reduction in LA passive emptying volume whereas global LA strain mechanics were not compromised in this study.

The Hen or the Egg: Impaired Alveolar Oxygen Diffusion and Acute High-altitude Illness?

Individuals ascending rapidly to altitudes >2500 m may develop symptoms of acute mountain sickness (AMS) within a few hours of arrival and/or high-altitude pulmonary edema (HAPE), which occurs typically during the first three days after reaching altitudes above 3000-3500 m. Both diseases have distinct pathologies, but both present with a pronounced decrease in oxygen saturation of hemoglobin in arterial blood (SO2). This raises the question of mechanisms impairing the diffusion of oxygen (O2) across the alveolar wall and whether the higher degree of hypoxemia is in causal relationship with developing the respective symptoms. In an attempt to answer these questions this article will review factors affecting alveolar gas diffusion, such as alveolar ventilation, the alveolar-to-arterial O2-gradient, and balance between filtration of fluid into the alveolar space and its clearance, and relate them to the respective disease. The resultant analysis reveals that in both AMS and HAPE the main pathophysiologic mechanisms are activated before aggravated decrease in SO2 occurs, indicating that impaired alveolar epithelial function and the resultant diffusion limitation for oxygen may rather be a consequence, not the primary cause, of these altitude-related illnesses.

Carbohydrate Intake in Form of Gel Is Associated With Increased Gastrointestinal Distress but Not With Performance Differences Compared With Liquid Carbohydrate Ingestion During Simulated Long-Distance Triathlon.

The ingestion of exogenous carbohydrates (CHO) during prolonged endurance exercise, such as long-distance triathlon, is considered beneficial with regard to performance. However, little is known about whether this performance benefit differs among different forms of CHO administration. To this end, the purpose of our study was to determine the impact of CHO ingestion from a semisolid source (GEL) on measures of performance and gastrointestinal (GI) comfort compared with CHO ingestion from a liquid source (LIQ). Nine well-trained triathletes participated in this randomized crossover study. Each participant completed a 60-min swim, 180-min bike exercise, and a 60-min all-out run in a laboratory environment under 2 conditions, once while receiving 67.2 ± 7.2 g · h-1 (M ± SD) of CHO from GEL and once while receiving 67.8 ± 4.2 g · h-1 of CHO from LIQ. The amount of fluid provided was matched among conditions. Respiratory exchange ratio (RER), blood glucose, and lactate as well as GI discomfort were assessed at regular intervals during the experiment. The distance covered during the final all-out run was not significantly different among participants ingesting GEL (11.81 ± 1.38 km) and LIQ (11.91 ± 1.53 km; p = .89). RER, blood glucose, and lactate did not differ significantly at any time during the experiment. Seven participants reported GI discomfort with GEL, and no athlete reported GI discomfort with LIQ (p = .016). This study suggests that administration of GEL does not alter long-distance triathlon performance when compared with LIQ, but GEL seems to be associated with reduced GI tolerance. Athletes should consider this a potential disadvantage of GEL administration during long-distance triathlon.

The valuable role of cardio-pulmonary exercise testing in the diagnosis of atrial septal defect in a competitive triathlete: a case report.

Background: Atrial septal defect (ASD) is characterized by a diverse clinical presentation influenced by the type, size, and haemodynamics. Endurance athletes with ASD may exhibit higher than normal performance levels, however they face an elevated risk of exercise-induced cardiac volume and pressure strain, potentially expediting a maladaptation of the right heart. Case summary: An asymptomatic 28-year-old female elite triathlete sought a pre-participation sports medical examination. Her past medical history revealed right heart enlargement. Transthoracic echocardiography and magnetic resonance imaging did not ascertain a definitive diagnosis such as shunting. The examination revealed a remarkably high maximum oxygen uptake during cardio-pulmonary exercise testing (CPET), yet an abnormal oxygen uptake/workload slope and a low, plateauing oxygen pulse. The athlete agreed to transoesophageal echocardiography that demonstrated a superior sinus venosus-type ASD. Surgical intervention, conducted with minimally invasive endoscopic robotic technology and a pericardial patch, was performed at a tertiary centre under full cardio-pulmonary bypass. At seven-month follow-up, the patient reported engaging in swim sessions without limitations and participating in high intensity cycling sessions with performances similar to pre-surgery. Cardio-pulmonary exercise testing revealed increased maximum oxygen consumption and normalization of oxygen uptake/workload slope and maximum oxygen pulse. Discussion: Endurance athletes with ASD may have abnormal haemodynamic response during CPET despite an exceptional high maximum oxygen uptake. This underscores the value of CPET in the diagnostic work-up of right heart enlargement.

Patient-Generated Health Data Interoperability Through Master Patient Index: The DH-Convener Approach.

Patient-Generated Health Data (PGHD), such as data provided by wearable devices, hold promise to improve health outcomes. However, to improve clinical decision-making, PGHD should be integrated or linked with Electronic Health Records (EHRs). Typically, PGHD data are collected and stored as Personal Health Records (PHRs), outside EHR systems. To address this challenge, we created a conceptual framework for PGHD/EHR interoperability through the Master Patient Index (MPI) and DH-Convener platform. Then, we identified the corresponding Minimum Clinical Data Set (MCDS) of PGHD to be exchanged with EHR. This generic approach can be used as a blueprint in different countries.

Roadmap for Aligning Cardiovascular Digital Health in Austria with the European Health Data Space (EHDS) Ecosystem.

Translating the proposed European Health Data Space (EHDS) regulations and requirements into reality is a challenging task. In this work, we provide a roadmap for aligning the EHDS requirement into the cardiovascular (CV) digital health domain in Austria. To achieve that, we first examined the current eHealth infrastructure and initiatives in Austria. Then, we created a CV-connected health model and addressed the challenges facing cardiac telerehabilitation in Austria. Finally, we mapped the European CV strategies to the Austrian context for EHDS implementation. Accordingly, we were able to provide an Enterprise Architecture (EA) framework for aligning CV digital health with the Austrian EHDS context. The created EA model can be also used as a guiding framework for aligning other medical domains in Austria with EHDS.

Can Patient Contributed Data (PCD) Leverage Connected Health Technology for Cardiac Rehabilitation in Austria?

New technologies such as devices, apps, smartphones, and sensors not only enable people to self-monitor their health but also share their health data with healthcare professionals. Data collection and dissemination occur across a wide variety of environments and settings, tracking everything from biometric data to mood and behavior, which has been termed Patient Contributed Data (PCD). In this work, we created a patient journey, enabled by PCD, to shape a connected health model for Cardiac Rehabilitation (CR) in Austria. Consequently, we highlighted the potential PCD benefit, which is a postulated increasing uptake of CR and improved patient outcomes through apps in a home-based setting. Finally, we addressed the related challenges and policy barriers that hinder the implementation of CR-connected health in Austria and identified actions to be taken.

Effect of digital tools in outpatient cardiac rehabilitation including home training-results of the EPICURE study.

Introduction: Cardiovascular diseases are the leading cause of death worldwide and are partly caused by modifiable risk factors. Cardiac rehabilitation addresses several of these modifiable risk factors, such as physical inactivity and reduced exercise capacity. However, despite its proven short-term merits, long-term adherence to healthy lifestyle changes is disappointing. With regards to exercise training, it has been shown that rehabilitation supplemented by a) home-based exercise training and b) supportive digital tools can improve adherence. Methods: In our multi-center study (ClincalTrials.gov Identifier: NCT04458727), we analyzed the effect of supportive digital tools like digital diaries and/or wearables such as smart watches, activity trackers, etc. on exercise capacity during cardiac rehabilitation. Patients after completion of phase III out-patient cardiac rehabilitation, which included a 3 to 6-months lasting home-training phase, were recruited in five cardiac rehabilitation centers in Austria. Retrospective rehabilitation data were analyzed, and additional data were generated via patient questionnaires. Results: 107 patients who did not use supportive tools and 50 patients using supportive tools were recruited. Already prior to phase III rehabilitation, patients with supportive tools showed higher exercise capacity (Pmax = 186 ± 53 W) as compared to patients without supportive tools (142 ± 41 W, p < 0.001). Both groups improved their Pmax, significantly during phase III rehabilitation, and despite higher baseline Pmax of patients with supportive tools their Pmax improved significantly more (ΔPmax = 19 ± 18 W) than patients without supportive tools (ΔPmax = 9 ± 17 W, p < 0.005). However, after adjusting for baseline differences, the difference in ΔPmax did no longer reach statistical significance. Discussion: Therefore, our data did not support the hypothesis that the additional use of digital tools like digital diaries and/or wearables during home training leads to further improvement in Pmax during and after phase III cardiac rehabilitation. Further studies with larger sample size, follow-up examinations and a randomized, controlled design are required to assess merits of digital interventions during cardiac rehabilitation.

Performance and reliability of two frequently used point-of-care blood gas analyzers at 423 and 4,559 m.

BACKGROUND AND OBJECTIVES: Blood gas analyzers (BGA) aid medical decision-making. Their specified performance criteria are based on sea level conditions. However, millions of people are living at high altitude (HA) where the performance of BGAs is poorly characterized. We investigated the effect of exposure to 4,559 m on the reliability and robustness of two BGAs widely used at HA. METHODS: In this prospective study arterial blood samples from 13 volunteers (2 female) with susceptibility to the development of high-altitude pulmonary edema were collected once near sea level at 423 m (nSL423) and three times at high altitude (HA4,559). Samples were measured in triplicate with the cartridge BGAs Rapidpoint 500 (SIE; Siemens Healthcare) and the ABL90 (RAD; Radiometer) to calculate coefficients of variation (CV) and intraclass correlation coefficients (ICC) within a mixed model. RESULTS: At nSL423 and HA4,559, 3% and 17% of all data were not reported with SIE, mainly due to clotting of the sample caused by delays because of the frequent automated calibration routines. No data were missing with RAD. ICCs were not significantly lower (mean (min-max) 0.87 (0.68-0.98) vs. 0.94 (0.84-1.00); p = 0.217) with SIE at nSL423, but significantly lower at HA4,559 (0.87 (0.49-1.00) vs. 0.99 (0.96-1.00); p = 0.025). All CVs, except that for arterial oxygen saturation at HA4,559,were higher with SIE . CONCLUSION: In this study, the reliability of RAD was superior to SIE at nSL423 and HA4,559. In contrast to RAD, the performance of SIE declined at HA4,559. SIE was more prone to not reporting all variables, especially at HA4559.

Asymmetric and symmetric dimethylarginine in high altitude pulmonary hypertension (HAPH) and high altitude pulmonary edema (HAPE).

Introduction: High altitude exposure may lead to high altitude pulmonary hypertension (HAPH) and high altitude pulmonary edema (HAPE). The pathophysiologic processes of both entities have been linked to decreased nitric oxide (NO) availability. Methods: We studied the effect of acute high altitude exposure on the plasma concentrations of asymmetric (ADMA) and symmetric dimethylarginine (SDMA), L-arginine, L-ornithine, and L-citrulline in two independent studies. We further investigated whether these biomarkers involved in NO metabolism were related to HAPH and HAPE, respectively. Fifty (study A) and thirteen (study B) non-acclimatized lowlanders were exposed to 4,559 m for 44 and 67 h, respectively. In contrast to study A, the participants in study B were characterized by a history of at least one episode of HAPE. Arterial blood gases and biomarker concentrations in venous plasma were assessed at low altitude (baseline) and repeatedly at high altitude. HAPE was diagnosed by chest radiography, and HAPH by measuring right ventricular to atrial pressure gradient (RVPG) with transthoracic echocardiography. AMS was evaluated with the Lake Louise Score (LLS) and the AMS-C score. Results: In both studies SDMA concentration significantly increased at high altitude. ADMA baseline concentrations were higher in individuals with HAPE susceptibility (study B) compared to those without (study A). However, upon high altitude exposure ADMA only increased in individuals without HAPE susceptibility, while there was no further increase in those with HAPE susceptibility. We observed an acute and transient decrease of L-ornithine and a more delayed but prolonged reduction of L-citrulline during high altitude exposure. In both studies SDMA positively correlated and L-ornithine negatively correlated with RVPG. ADMA was significantly associated with the occurrence of HAPE (study B). ADMA and SDMA were inversely correlated with alveolar PO2, while L-ornithine was inversely correlated with blood oxygenation and haemoglobin levels, respectively. Discussion: In non-acclimatized individuals ADMA and SDMA, two biomarkers decreasing endothelial NO production, increased after acute exposure to 4,559 m. The observed biomarker changes suggest that both NO synthesis and arginase pathways are involved in the pathophysiology of HAPH and HAPE.

Investigating shared decision-making during the use of a digital health tool for physical activity planning in cardiac rehabilitation.

Background: Shared decision making (SDM) between healthcare professionals and persons with CVD can have a positive impact on motivation, adherence, or sustainability regarding long-term goals and integration of cardiovascular disease (CVD) rehabilitation in the everyday lives of persons with CVD. SDM can foster the transition between regular heart-healthy activity at rehabilitation facilities and more independent activity at home, but it is often challenging to implement SDM given limited time and resources, e.g., in the daily practice of rehabilitation. Digital tools can help but must be appropriately tailored for situated use and user needs. Objective: We aimed to (1) describe in how far SDM is manifested in the situated context when using a digital tool developed by our group, and, based on that, (2) reflect on how digital health tools can be designed to facilitate and improve the SDM process. Methods: In the context of a field study, we investigated how SDM is already naturally applied and manifested when using a digital tool for joint physical activity planning in cardiac rehabilitation in clinical practice. In a two-week qualitative study, we collected data on expectations, experiences and interactions during the use of a digital health tool by seven persons with CVD and five healthcare professionals. Data was collected by means of observations, interviews, questionnaires and a self-reported diary, and analysed with a particular focus on episodes related to SDM. Results: We found that SDM was manifested in the situated context to limited extent. For example, we identified high improvement potential for more structured goal-setting and more explicit consideration of preferences and routines. Based on mapping our findings to temporal phases where SDM can be adopted, we highlight implications for design to further support SDM in clinical practice. We consider this as "SDM supportive design in digital health apps," suggesting for example step-by-step guidance to be used during the actual consultation. Conclusion: This study contributes to further understanding and integration of SDM in digital health tools with a focus on rehabilitation, to empower and support both persons with CVD and healthcare professionals.

Exertional Dyspnea as the Main Symptom in an Adolescent Athlete With Coronary Artery Anomaly - A Case Report.

Coronary artery anomalies (CAA) are associated with sudden cardiac death (SCD) and the majority of those events occur during exercise. Depending on the anatomic features and severity, CAA usually provoke clinical symptoms of coronary ischemia, mainly syncope and (exertional) chest pain. Here we present a case of a female adolescent athlete with a high-risk CAA variant and an unusual clinical presentation, which delayed diagnosis 2 years after first symptoms were reported. After successful surgical management of the anomalous artery, the patient was determined eligible for competitive sports with unremarkable follow-up examinations.

Overview of Existing Tools for Extracting Health and Fitness Data from mHealth Apps.

Wearable sensors and mHealth apps collect fitness and health data outside of clinical settings. These data are essential for precision medicine. This paper addresses and analyzes the available tools for extracting health and fitness data from wearables and mHealth apps. We focus on the most common tools used for research, namely, the Open mHealth-Shimmer application and Fitrockr research platform.