Lower VO2 Research Articles

Abstract EP18: Cardiopulmonary Testing In Long Covid Versus Non-CovidPatients With Undifferentiated Dyspnea On Exertion

Background: COVID-19 reveals new manifestations not only in the acute phase but also in the long term. The latter is what has been termed as ‘post acute sequelae of SARS-CoV-2 infection’ (PASC) — or “long COVID”— with dyspnea as one of its hallmarks. Cardiopulmonary stress testing (CPET) is increasingly being used to better evaluate such patients. Objective: To compare CPET findings of long COVID patients versus non-COVID patients with undifferentiated dyspnea on exertion seen at Mayo Clinic. Methods: A cohort study was carried out using Mayo Clinic’s exercise testing database. The study group included 77 PASC patients confirmed by a positive antigen or PCR test with no prior history of heart or lung disease. PASC patients were compared to 766 non-COVID patients with unspecified dyspnea without known diagnosis of cardiac or pulmonary disease. ANOVA according to the general linear model and Pearson’s Chi square were used for the bivariate analysis of the quantitative and categorical variables, respectively. Analyses were controlled for age, sex, and beta blocker use as appropriate. Both HR and SBP at rest and peak exercise were significantly different between groups, although the absolute differences were small. Results: Compared with the control group, the post-COVID patients were younger (mean age 47 SD ±14.9 years versus 50.5 SD ±10.1 years) and more likely to be female (70.1% (54 of 77) vs 57.6% (441 of 766)). Although there were many significant differences in the CPET results, the most outstanding were a lower FAC (73 SD ±19.4% vs 85.2 SD ±20.8%) and peak VO2 (22 SD ±6.4 ml/kg/min vs 25.8 SD ±7.37 ml/kg/min) in the study group (p<.0001). Also, CNS changes during CPET were reported at higher rates (19.5% (15 of 77) vs 11.4% (87 of 766)) while dyspnea at lower rates (55.8% (43 of 77) vs 65.7% (503 of 766)) in post-COVID patients (p=0.02). When adjusting for age and sex, weight was significantly higher in the study group (p=0.03) although the absolute difference was modest and BMI remained not significant. PFTs did not suggest any pulmonary abnormalities. Conclusions: We identified a high rate of severe exercise limitation among long COVID patients. Young women may be at higher risk for these complications. Pre-exercise PFTs and absence of objective respiratory limitation during CPET argue against a primary pulmonary cause of the observed limitations, though evaluation of cardiac, autonomic, and muscular impairment is pending. Further studies are warranted to untangle the physiologic abnormalities responsible for these observations.

Differences between Sexes in Cardiopulmonary Fitness among Children and Adolescents with Kawasaki Disease.

It is known that children and adolescents with Kawasaki disease (KD) can maintain normal cardiopulmonary fitness (CPF) after the disease’s acute stage has subsided. This study aimed to investigate whether gender differences affect CPF in children and adolescents with KD. We retrospectively reviewed a cohort of 204 participants (120 boys and 84 girls) with KD. All participants were instructed to complete a symptom-limited cardiopulmonary exercise test (CPET) adapted to assess their CPF. Based on body mass index (BMI), boys and girls were categorized into groups of underweight (19 boys and 12 girls), normal (62 boys and 59 girls), and overweight (39 boys and 13 girls). Although a similarity in body composition was found among both genders for KD subjects and normal Taiwanese peers, the percentage of overweight subjects was higher in KD boys than the normal Taiwanese boys. When comparing CPF for different BMI groups, the whole KD group showed no discrepancy, but a significantly lower peak VO2 for the overweight KD boys group was observed, representing poorer CPF. In conclusion, girls with KD had better CPF than boys, and gender stereotypes affect sports participation as well as self-efficacy, and may be contributing to poorer CPF in KD boys.

Physical fitness in patients with bipolar disorder compared with a population-based sample.

BackgroundThis study aimed to evaluate physical fitness and body composition in a sample including hospitalized patients with bipolar disorder and to compare them with a population‐based sample.MethodsIn this comparative observational study, 40 bipolar patients and 40 healthy subjects in Taleghani Hospital, Tehran, Iran, in 2019 were assessed. The physical fitness items such as body mass index (BMI), body fat, push‐up test, curl‐up test, VO2 peak, and sit and reach test were compared across the groups. Young Mania Rating Scale for assessing the severity of bipolar disease and WHODAS2.0 for the estimation of global performance were done in the case group.ResultsThe results of this study demonstrate that sit and reach test, body mass index (BMI), and body fat percent were similar across the studied groups. The push‐up test, curl‐up test, and VO2 peak (P = .001) were significantly lower in the case group. In the case group, only the push‐up test was associated with the severity of bipolar disorder and decreased performance.ConclusionLower push‐up and curl‐up can indicate an increase in both back and neck pains in these patients. Low VO2 peak in these patients increases the risk of heart disease and mortality rates in bipolar patients. The push‐up test can be used as a screen test to estimate the severity of the bipolar disorder.

Three dimensional myocardial deformation parameters are associated with functional capacity in hypertrophic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Three-dimensional (3D) echocardiography is an emerging tool for assessment of left ventricular function, with a promising role in the evaluation of cardiomyopathies. Hypertrophic cardiomyopathy (HCM) is often associated with reduced exercise capacity. The aim of this study was to evaluate the importance of 3D myocardial deformation parameters as predictors of exercise capacity in HCM patients (P). Methods This prospective study enrolled P with HCM. Each P underwent a comprehensive transthoracic echocardiogram including 3D speckle-tracking to measure global longitudinal, radial and circumferential strain, twist, torsion and global area strain. Functional capacity was objectively assessed by treadmill cardiorespiratory exercise testing. Results 83 patients with HCM, 50 (60%) male, mean left ventricular ejection fraction (LVEF) of 68 ± 7%, 27 (33%) with obstructive HCM (LV outflow tract [LVOT] gradient of 89 ± 60 mmHg). Impairment in LV myocardial deformation parameters was significantly correlated with lower peak VO2: global longitudinal 3D strain (r=-0.397, p < 0.001), global radial 3D strain (r = 0.336, p = 0.003) and global circumferential 3D strain (r=-0.353, p = 0.002) (Figure 1). Impaired LV twist was significantly correlated with inferior peak VO2 (r = 0.264, p = 0.033) (Fig.2) and peak circulatory power (r = 0.371, p = 0.003). Torsion impairment also significantly associated with lower peak VO2 (r = 0.285, p = 0.021), circulatory power (r = 0.380, p = 0.002), time to ventilatory anaerobic threshold (VAT) (r = 0.369, p = 0.003) and (VE/VCO2 slope)/peak VO2 ratio (r=-0.316, p = 0.012). Furthermore, global area strain impairment showed significant relation with decreased peak VO2 (r=-0.368, p = 0.001), lower exercise duration (r=-0.384, p = 0.001), time to VAT (r=-0.404, p < 0.001), circulatory power (r=-0.272, p = 0.032) and (VE/VCO2 slope)/peak VO2 ratio (r = 0.391, p = 0.002). LV twist (r=-0.135, p = 0.284), torsion (r=-0.120, p = 0.341) and global area strain (r = 0.152, p = 0.235) impairment did not correlate with VE/VCO2 slope. Exercise capacity was not associated with LV mass index (r = 0.209, p = 0.095), LV end-diastolic volume (r = 0.058, p = 0.639), maximum wall thickness (r = 0.041, p = 0.744), LVEF (r=-0.092, p = 0.458), 2D global longitudinal strain (r=-0.024, p = 0.848) or peak LVOT gradient (r=-0.006, p = 0.964). In a subanalysis examining only the nonobstructive (nHCM) P, we found that peak VO2 had a superior correlation with global longitudinal 3D strain (r=-0.420, p = 0.004), global radial 3D strain (r = 0.356, p = 0.016) and global circumferential 3D strain (r=-0.357, p = 0.016) as well as LV twist (r = 0.300, p = 0.046) and torsion (r = 0.336, p = 0.024). Conclusion Although P with HCM often have supranormal LVEF, 3D speckle-tracking echocardiographic imaging has the potential to demonstrate subclinical impairment of LV function. Impaired LV 3D strain, twist, torsion and global area strain were associated with reduced exercise capacity, particularly in nHCM P. Abstract Figure. Peak VO2 and 3D strain parameters Abstract Figure. LV twist, torsion and global area strain

Retinal Oxygen Delivery and Extraction in Ophthalmologically Healthy Subjects With Different Blood Pressure Status.

PurposeTo compare retinal oxygen delivery (DO2) and oxygen extraction (VO2) in ophthalmologically healthy subjects with different blood pressure (BP) status.MethodsIn this case-control study, we prospectively included 93 eyes of 93 subjects (aged 50–65 years) from a Dutch cohort (n = 167,000) and allocated them to four groups (low BP, normal BP [controls], treated arterial hypertension [AHT], untreated AHT). We estimated vascular calibers from fundus images and fractal dimension from optical coherence tomography angiography scans. We combined calibers, fractal dimension, BP, and intraocular pressure measurements in a proxy of retinal blood flow (RBF), using a Poiseuille-based model. We measured arterial and venous oxygen saturations (SaO2, SvO2) with a scanning laser ophthalmoscope. We calculated the DO2 and VO2 from the RBF, SaO2, and SvO2. We compared the DO2 and VO2 between groups and investigated the DO2–VO2 association.ResultsDO2 and VO2 were different between groups (P = 0.009, P = 0.036, respectively). In a post hoc analysis, the low BP group had lower DO2 than the untreated AHT group (P = 4.9 × 10−4). The low BP group and the treated AHT group had a lower VO2 than the untreated AHT group (P = 0.021 and P = 0.034, respectively). There was a significant DO2–VO2 correlation (Robs = 0.65, bobs = 0.51, P = 2.4 × 10−12). After correcting for shared measurement error, the slope was not significant.ConclusionsThe DO2 and VO2 were altered in ophthalmologically healthy subjects with different BP status. Future studies could elucidate whether these changes can explain the increased risk of ophthalmic pathologies in those subjects.Translational RelevanceUnderstanding the baseline interplay between BP, retinal perfusion, and oxygenation allows for improved evaluation of retinal disease manifestation.

Differential Influence of Physical Activity on Cardiopulmonary Performance and Stroke Volume Assessed at Cardiopulmonary Exercise Test in Pectus Excavatum: A Pilot Study.

BackgroundExercise training increases muscle VO2 by increasing O2 transport and O2 uptake while cardiac output increase might be limited by the conformation of the chest in subjects with pectus excavatum (PE).AimsThe aim of the present study was to investigate the influence of physical activity (PA) on functional parameters of cardiopulmonary performance and stroke volume obtained at Cardiopulmonary Exercise Test (CPET) in PE.Methods and ProceduresA cohort of adolescents (15 with PE and 15 age- and sex-matched healthy controls, HC) underwent Cardiopulmonary Exercise Test (CPET) and administration of the International Physical Activity Questionnaire – Short Form (IPAQ-SF) with estimation of weekly PA (METs h–1⋅week–1). Determinants of CPET parameters were investigated with multivariable linear regression analysis.ResultsAs expected, when compared to HC, PE had lower VO2 max (37.2 ± 6.6 vs. 45.4 ± 6.4 mL⋅kg–1⋅min–1, p < 0.05), and VO2/HR max (O2 pulse, 12.1 ± 2.4 vs. 16.2 ± 3.6 mL⋅min–1⋅bpm–1, p < 0.05). Importantly, physical activity level was a predictor of VO2 max (adjusted for sex, body mass index, FEV1%, and presence of PE, β = 0.085; 95% Cl 0.010 to 0.160, p = 0.029) whereas O2 pulse was independent from PA level (β = 0.035; 95% Cl −0.004 to 0.074).ConclusionPhysical activity is a determinant of VO2 max (cardiopulmonary performance), whereas it appears not to affect O2 pulse (a measure of stroke volume at peak exercise) related to constrained diastolic filling in PE.

Improved performance of vanadium redox flow battery with tuneable alkyl spacer based cross-linked anion exchange membranes

We synthesize cross-linked aliphatic polymer with side chain grafted imidazole based anion exchange membranes (AEMs) using alkyl chain spacer. Prepared AEMs exhibit excellent stabilities, ionic conductivity, and vanadium ion impervious nature. These AEMs with rigid polymer matrix show low swelling ratio in spite of high molality of exchangeable functional groups. Cross-linked methylmethacrylate-co-vinyl imidazole copolymer (CMVI) with C3 spacer (CMVI-C3) possess 1.21 meq/g ion exchange capacity, and 8.1 × 10−2 S/cm conductivity. Well optimized CMVI-C3 AEM shows extremely low VO2+ permeability (1.96 × 10−9 cm2 s−1) in comparison to Nafion 117 (16.34 × 10−9 cm2 s−1), due to blocking property of CMVI AEMs for VO2+. At 120.0 mA cm−2, relatively high Coulombic (98.8%), energy (78.2%), and voltage (80.5%) efficiencies of CMVI-C3 AEM in comparison with Nafion 117 membrane, has been attributed to synergetic balance between hydrophobic and hydrophilic segments. The CMVI-C3 AEM maintains the high performance and good integrity during in-situ VRFB cycle performance assessment up to 200 cycles. Simple method for the preparation, good stabilities, and high performance are attractive features of CMVI-C3 AEM for vanadium redox flow battery.

A reflective millimeter-wave photonic limiter.

Millimeter-wave (mm-wave) communications and radar receivers must be protected from high-power signals, which can damage their sensitive components. Many of these systems arguably can be protected by using photonic limiting techniques, in addition to electronic limiting circuits in receiver front-ends. Here we demonstrate, experimentally and numerically, a free-space, reflective mm-wave limiter based on a multilayer structure involving a nanolayer of vanadium dioxide VO2, which experiences a heat-related insulator-to-metal phase transition. The multilayer acts as a variable reflector, controlled by the incident wave intensity. At low intensities VO2 remains dielectric, and the multilayer exhibits strong resonant transmittance. When the incident intensity exceeds a threshold level, the emerging metallic phase renders the multilayer highly reflective while safely dissipating a small portion of the input power, without damage to the limiter. In the case of a Gaussian beam, the limiter has a nearly constant output above the limiting threshold input.

Effect of pulmonary hypertension on exercise capacity and gas exchange in patients with chronic obstructive pulmonary disease living at high altitude.

Background: Pulmonary hypertension (PH) is associated with decreased exercise tolerance in chronic obstructive pulmonary disease (COPD) patients, but in the altitude the response to exercise in those patients is unknown. Our objective was to compare exercise capacity, gas exchange and ventilatory alterations between COPD patients with PH (COPD-PH) and without PH (COPD-nonPH) residents at high altitude (2640 m). Methods: One hundred thirty-two COPD-nonPH, 82 COPD-PH, and 47 controls were included. Dyspnea by Borg scale, oxygen consumption (VO2), work rate (WR), ventilatory equivalents (VE/VCO2), dead space to tidal volume ratio (VD/VT), alveolar-arterial oxygen tension gradient (AaPO2), and arterial-end-tidal carbon dioxide pressure gradient (Pa-ETCO2) were measurement during a cardiopulmonary exercise test. For comparison of variables between groups, Kruskal-Wallis or one-way ANOVA tests were used, and stepwise regression analysis to test the association between PH and exercise capacity. Results: All COPD patients had a lower exercise capacity and higher PaCO2, A-aPO2 and VD/VT than controls. The VO2 % predicted (61.3 ± 20.6 vs 75.3 ± 17.9; p < 0.001) and WR % predicted (65.3 ± 17.9 vs 75.3 ± 17.9; p < 0.001) were lower in COPD-PH than in COPD-nonPH. At peak exercise, dyspnea was higher in COPD-PH (p = 0.011). During exercise, in COPD-PH, the PaO2 was lower (p < 0.001), and AaPO2 (p < 0.001), Pa-ETCO2 (p = 0.033), VE/VCO2 (p = 0.019), and VD/VT (p = 0.007) were higher than in COPD-nonPH. In the multivariate analysis, PH was significantly associated with lower peak VO2 and WR (p < 0.001). Conclusion: In COPD patients residing at high altitude, the presence of PH was an independent factor related to the exercise capacity. Also, in COPD-PH patients there were more dyspnea and alterations in gas exchange during the exercise than in those without PH.

53 Exercise oxygen kinetic in hypertrophic cardiomyopathy: results from a multicentre cardiopulmonary exercise testing study

Abstract Aims Reduced cardiac output (CO) has been considered crucial in symptoms’ genesis in hypertrophic cardiomyopathy (HCM). We evaluated the cardiopulmonary exercise testing (CPET) response in HCM focusing on parameters strongly associated with stroke volume (SV) and cardiac output (CO), such as oxygen uptake (VO2) and O2-pulse, considering both their absolute values and temporal behaviour during physical exercise. Methods and results We enrolled 312 non-end stage HCM patients, divided according to left ventricle outflow tract obstruction (LVOTO) at rest or during Valsalva manoeuver (72% with LVOTO &amp;lt; 30; 10% between 30 and 49; and 18% ≥50 mmHg). Peak VO2 (percent of predicted), O2-pulse, and ventilation to carbon dioxide production (VE/VCO2) slope did not change across LVOTO groups. Ninety-six (31%) HCM patients presented an abnormal O2-pulse temporal behaviour, irrespective of LVOTO values. These patients showed lower peak systolic pressure, workload (106 ± 45 vs. 130 ± 49 W), VO2 (74 ± 17% vs. 80 ± 20%) and O2-pulse (12 [9–14] vs. 14 [11–17]ml/beat), with higher VE/VCO2 slope (28 [25–31] vs. 27 [24–31]) (P &amp;lt; 0.005 for all). Only two patients had an abnormal VO2/work slope. Conclusions None of CPET parameters, either as absolute values or dynamic relationships, were associated with LVOTO. Differently, an abnormal O2-pulse exercise behaviour, which is strongly related to inadequate SV during exercise, correlates with reduced functional capacity (peak and anaerobic threshold VO2 and workload) and increased VE/VCO2 slope, helping identifying more advanced disease irrespectively of LVOTO. Adding O2-pulse kinetics evaluation to standard CPET could lead to a potential incremental benefit in terms of HCM prognostic stratification and, then, therapeutic management.

New crosslinked membranes based on cardo-poly(etherketone) and poly(ethylene imine) for the vanadium redox flow battery

• Low-cost membranes for VFRBs are synthesized by crosslinking PEI with PEKC. • x %PEI-PEKC membranes exhibt low AR and low VO 2+ permeability simultenously. • The 50%PEI-PEKC membrane displays superior VRFB efficiencies and cycling stability. Developing polymer membranes with low cost, high ionic conduction and low vanadium ion permeability simultaneously for the vanadium redox flow battery (VRFB) is a huge challenge to macromolecule design and engineering. Herein, a series of high-performance and low-cost macromolecule cross-linked membranes for VRFB are synthesized from cardo-poly(etherketone) (PEKC) and poly(ethylene imine) (PEI) through a straightforward lactamization reaction between the primary amines in PEI and lactones in PEKC. Owing to the acid-base interaction between amino groups of PEI and sulfonic acid (SA), crosslinked x %PEI-PEKC membranes exhibit excellent SA adsorption capability and low area resistance. Meanwhile, the formed macromolecule multi-crosslinked networks significantly improve the membrane-forming property of PEI and endow membranes with superior mechanical rigidity and low vanadium ion permeability simultaneously. Consequently, the 50%PEI-PEKC membrane exhibit a nearly 90 times higher ion selectivity of 24.71 × 10 5 S min cm −3 than Nafion 115. The assembled VRFB with 50%PEI-PEKC displays higher battery efficiencies than Nafion 115 at 60–160 mA cm −2 , which also possesses superior cycling stability at 100 mA cm −2 .

Abstract 12407: A Comparison of Hemodynamic and Cardiopulmonary Exercise Stress Variables for Advanced Heart Failure Prognosis

Introduction: Both invasive hemodynamics as measured by right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET) are used for prognostication in advanced heart failure patients. We aimed to compare the prognostic performance of these variables in patients with advanced heart failure with a particular focus on defining the incremental prognostication of advanced hemodynamic metrics compared to CPET variables. Methods: We retrospectively analyzed patients who underwent both a RHC and CPET within one year of each other from January 2013 to January 2019 at our institution. The CPET variables of peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2), oxygen pulse (VO2/HR), and the RHC variables of left ventricular stroke work index (LVSWI), cardiac power output (CPO), and aortic pulsatility index (API) were used. The primary outcome was death, left ventricular assist device, or heart transplant at one year following the RHC. Results: A total of 55 patients were included in the analysis: 35% women, 51% Black, and 27% ischemic cardiomyopathy. Overall, using Spearman’s analysis, there were no significant correlations between the RHC and CPET variables. On Kaplan-Meier analysis, lower LVSWI was significantly associated with the primary outcome when compared to lower VO2/HR, HR 5.3 (95% CI 1.2-23, p = 0.02.), lower VE/VCO2, HR 3.7 (95% CI 1.3-10.4, p = 0.014), and lower peak VO2, HR 7.0 (95% CI 0.9-56, p = 0.06). Conclusion: LVSWI is more associated with one-year outcomes in patients with advanced heart failure than other prognostic hemodynamic or CPET variables. Furthermore, advanced hemodynamic metrics are more prognostic than CPET measurements when these values are discordant.

Abstract 14269: The Association of Treadmill Exercise Test-Derived VO 2 Max and Symptomology in Athletes and Non-Athletes With Hypertrophic Cardiomyopathy

Introduction: Hypertrophic cardiomyopathy (HCM) is a major cause of sudden cardiac death in the young and especially in young athletes. The treadmill exercise test (TEST) has an important role in the functional assessment of patients with HCM. Herein, TEST-derived peak oxygen uptake (VO2 max) is a proxy for cardiopulmonary fitness. However, the correlation between symptoms and VO2 - especially in active young patients with HCM - is unclear. Objective: To explore the relationship between TEST-derived VO2 and symptomology in athletes and non-athletes with HCM. Methods: Overall, 91 patients (40% female) with HCM and a TEST with VO 2 data were included in this case-control study. Data were abstracted from the electronic health record using the first TEST performed at Mayo Clinic. Patients were defined as an athlete if they participated in an organized, competitive sport. Results: Overall, 60 HCM patients (33% female) were categorized as an athlete. HCM athletes were younger (17 vs. 27 years; p&lt;0.0001) and less likely to be symptomatic at the time of their TEST (OR=0.24; p=0.01). Additionally, athletes had a higher VO2 max (86% vs. 68% of predicted; p&lt;0.0001) and reached higher exercise times (93% vs 76% of predicted; p&lt;0.0001) compared to the non-athletes with HCM. When comparing symptomatic (n = 18) to asymptomatic patients (n = 73), symptomatic patients had i) a reduced exercise time (68% vs. 92% of predicted; p=0.002) and ii) lower VO2 max (62% vs 84% of predicted; p&lt;0.001). Finally, among the 27 patients (30%) with a VO 2 max &lt; 70% predicted (n=27), they i) more likely had a history of cardiac arrest (4 vs 0; p=0.006) and ii) were more likely to be symptomatic (OR=7.7; p&lt; 0.0001) than those with VO2 ≥ 70% of predicted (n=64). Importantly, however, 15/27 (56%) patients (8 athletes/7 non-athletes) with a VO2 max &lt; 70% were asymptomatic. Conclusions: Reduced exercise capacity is common in athletes with HCM and does not correlate with symptom status. However, if the TEST-derived VO2 max is &lt; 70%, treatment intensification may be necessary as it may portend an adverse outcome both arrhythmically and mechanically.

Abstract 9310: Aortic Arch Shape After Coarctation Repair Predicts Exercise Capacity: A Multicenter Analysis

Introduction: Patients with coarctation of the aorta (CoA) have decreased exercise capacity despite successful repair with no anatomic obstruction. Altered aortic arch shape after surgical repair may increase resistance to flow and affect flow distribution. This study correlates parameters of aorta size and flow with exercise capacity after successful CoA repair. Methods: We retrospectively reviewed patients with repaired CoA at 4 centers who had cardiac magnetic resonance imaging (CMR) and an exercise stress test with respiratory exchange ratio ≥ 1.09 within 1 year. Patients with significant valve disease, outflow tract obstruction, or need for cardiac bypass outside of their arch repair were excluded. Aorta size mismatch (D AAo /D DAo ), defined by the ratio of ascending (AAo) to proximal descending aorta (DAo) diameter, and DAo flow as a percentage of AAo flow, were measured from CMR. Each parameter was correlated with percent predicted peak oxygen consumption (VO2 max). Results: Forty-six patients (age 26 ± 8.4 years) with left ventricular ejection fraction (LVEF) &gt; 52%, met inclusion criteria. Larger D AAo /D DAo and lower %DAo flow correlated significantly with lower VO2 max (Fig). Compared to those with normal VO2 max (n=25), patients with VO2 max &lt;90% predicted (n=21) had a primary repair at an older age (p=0.03) and smaller DAo diameter/m 2 (p=0.04). There were no significant differences in prevalence of arch obstruction by echocardiogram, LVEF, hypertension, blood pressure gradient at rest or exercise, or AAo diameter/m 2 between groups. Conclusions: Aorta size mismatch, due to AAo dilation or small DAo, and associated decreased %DAo flow, correlate significantly with decreased exercise capacity after CoA repair in patients with normal left ventricular systolic function. CMR measurements of aorta geometry and flow can inform the definition of a successful repair and suggest that indications for re-intervention may not be limited to discrete re-coarctation.

Renin-Angiotensin System Blockade Is Associated with Exercise Capacity, Sympathetic Activity, and Endothelial Function in Patients with Chronic Kidney Disease

Background: Chronic kidney disease (CKD) patients have exercise intolerance and exaggerated blood pressure reactivity during exercise that are mediated by sympathetic nervous system (SNS) overactivation and decreased nitric oxide (NO) bioavailability. The activation of the renin-angiotensin system (RAS) increases SNS activation and reduces NO synthesis, and prior studies suggest that RAS blockade attenuates declines in physical function. We hypothesized that RAS inhibitor (RASi) use is associated with higher exercise capacity mediated by decreased SNS activity and increased NO-dependent endothelial function in CKD. Method: In 35 CKD patients (57 ± 7 years) and 20 controls (CONs) (53 ± 8 years), we measured exercise capacity (peak oxygen consumption [VO_2peak]), muscle sympathetic nervous activity (MSNA), and flow-mediated dilation (FMD) for NO-dependent endothelial function. Results: CKD patients treated with RASi (CKD + RASi, n = 25) had greater VO_2peak than CKD patients not treated with RASi (CKD no RASi, n = 10), but lower VO_2peak than CONs (23.3 ± 5.8 vs. 16.4 ± 2.9, p = 0.007; vs. 30.0 ± 7.7, p = 0.016 mL/min/kg, respectively). CKD + RASi had lower resting MSNA and greater FMD than CKD no RASi. Compared to CONs, CKD + RASi had similar MSNA but lower FMD. VO_2peak was positively associated with FMD (r = 0.417, p = 0.038) and was predicted by the combination of FMD and RASi status (r² = 0.344, p = 0.01) and MSNA and RASi status (r² = 0.575, p = 0.040) in CKD patients. Conclusion: In summary, CKD patients with RASi have higher exercise capacity than those not on RASi. Higher exercise capacity in the RASi-treated group was associated with lower resting SNS activity and higher NO-dependent vascular endothelial function.

A multi-component intervention to affect physical activity, sleep length and stress levels in office workers

Physical inactivity, insufficient sleep and prolonged high stress levels are well documented risk factors for premature death. Yet, modern lifestyle is associated with high prevalence of these risk factors. This multi-component intervention aims to enhance and support healthy behaviors in office-workers. Sixty-three participants (28 males, with a mean age of 42 years, SD 11, range: 24–68 years) were included at three workplaces. A control period (four weeks) was followed by an intervention period (eight weeks). The intervention included a personal approach to enhance physical activity, restrictions on the use of bedtime technology and the application of a wrist-worn device tracking physical activity, sleep, and stress. After the intervention period, an increase of aerobic capacity was observed with 2.05 mL/kg/min (P < 0.001). Total sleep time was unchanged while sleep onset was postponed 10 min (P < 0.001) in the intervention period compared to the control period. Lower stress levels based on heart rate variability were observed in the intervention period compared to the control period (P = 0.001). Our results suggest that a multi-component intervention can increase physical activity resulting in an improved maximal oxygen uptake in office-workers. Stress levels may decrease especially for those with an initially low VO 2 max while restricting use of technology use in the bedroom has no effect on sleep length. The results suggest that increasing PA through an individual approach supported by a WTD is accompanied by noteworthy health benefits while restricting bedtime technology use has limited effect on sleep measures. • This study targets physical activity, sleep and stress behaviors simultaneously among a population of office-workers. • An individual approach to enhance physical activity combined with the use of a wearable tracking device can increase VO 2 max. • Restricting technology use within the bedroom has no effect on sleep length. • Objectively measured stress levels may decrease especially for those with an initially low VO 2 max.

Left ventricular diastolic dysfunction in non-severe chronic obstructive pulmonary disease as a step forward in cardiovascular comorbidome

Abstract Background Chronic obstructive pulmonary disease (COPD) augments the likelihood of having left ventricular diastolic dysfunction (LVDD) – precursor of heart failure with preserved ejection fraction (HFpEF). LVDD shares overlapping symptomatology (cough and dyspnea) with COPD. Purpose Our aim was to evaluate the predictive value of inflammatory, oxidative stress, cardio-pulmonary and echocardiographic parameters at rest for the diagnosis of stress LVDD in non-severe COPD patients, who complain of exertional dyspnea and are free of overt cardiovascular diseases. Methods A total of 104 COPD patients underwent echocardiography before cardio-pulmonary exercise testing (CPET) and 1–2 minutes after peak exercise. Patients were divided into two groups based on peak E/e': patients with stress induced left ventricular diastolic dysfunction (LVDD) - E/e' &amp;gt;15 (HFpEF) and patients LVDD (without HFpEF). CPET and echocardiographic parameters at rest were measured and their predictive value for stress E/e' was analysed. Markers for inflammation (resistin, prostaglandine E2) and oxidative stress (8-isoprostanes) were also determined. Results Stress induced LVDD occurred in 67/104 patients (64%). Those patients had lower work load, lower VO2 consumption, lower minute ventilation and higher VE/VCO2 slope in comparison to patients without. Except for prostglandine E2, none of the inflammatory, oxidative stress markers correlated to stress E/e'. The best independent predictors for HFpEF were RAVI, right ventricular parasternal diameter and RV E/A &amp;gt;0.75. Their combination predicted HFpEF with the accuracy of 91.2%. Conclusion There is a high prevalence of HFpEF in non-severe COPD with exertional dyspnea, free of overt cardiovascular disease. RAVI, right ventricular parasternal diameter and RV E/A &amp;gt;0.75 were the only independent clinical predictors of HFpEF. Funding Acknowledgement Type of funding sources: None.

Insulin resistance-related differences in the relationship between left ventricular hypertrophy and cardiorespiratory fitness in asymptomatic newly diagnosed hypertensive Black sub-Saharan Africans

Abstract Background Left ventricular hypertrophy (LVH) is associated with impaired cardiorespiratory fitness (CRF), a surrogate marker of poor outcome. Insulin resistance (IR) plays a central role in all stages of cardiovascular disease continuum. Purpose This study evaluates IR-related differences in the relationship between left ventricular mass (LVM) and CRF in asymptomatic newly diagnosed hypertensive patients. Methods In this cross-sectional observational study, 126 asymptomatic newly diagnosed hypertensive participants (50.5±9.5 years) underwent comprehensive resting transthoracic echocardiographic examination and maximal incremental cardiopulmonary exercise test (CPET). CRF was estimated in peak oxygen uptake (VO2 peak). CPET results were compared between participants with and without LVH. Multivariate analysis examined the influence of IR on the observed differences. Results Those with LVH had lower VO2 peak (15.7±5.5 mL min–1 kg–1 vs. 18.4±3.7 mL min–1 kg–1; p=0.001) than those without LVH. In patients with IR, LVM (r=−0.261, p=0.012), LVM indexed to body surface area (LVMIbsa; r=−0.229, p=0.027), and LVM indexed to height to an allometric power of 2.7 (LVMIh2.7; r=−0.351, p=0.001), and VO2 peak were negatively correlated. In hypertensive patients without IR, these same parameters and VO2 peak have no significant correlation. Body mass index (BMI), LVM, and LVMIbsa emerged as independent determinants of VO2 peak, explaining 46.9% of its variability (overall p=0.001) in IR participants, a relationship not found in participants without IR. Conclusions IR may participate in the deterioration of CRF associated with LVH. Targeting IR in hypertensive patients with LVH could improve prognosis. Funding Acknowledgement Type of funding sources: None.

Comprehensive Study of Heart Rate Recovery and Altered Ventilatory Response to Exercise in Patients with Obstructive Sleep Apnea

Abstract Background Obstructive sleep apnea (OSA) is a chronic disorder that results in many cardiovascular disorders including hypertension, arrhythmias and congestive heart failure (CHF). Polysomnography is the gold standard for diagnosis of OSA, even though up to 93% of women and 82% of men with moderate to severe OSA still remain undiagnosed. Cardiopulmonary exercise testing (CPXT) has been conventionally used for evaluation of coronary artery diseases and rehabilitation of cardiac patients. Modern systems allow for the analysis of gas exchange at rest, during exercise, and during recovery and also yield measures of oxygen uptake (V O2), carbon dioxide output (V CO2), and minute ventilation (V E) together with heart rate, blood pressure, electrocardiography findings, and symptoms. This may have clinical utility if added to the available screening tools used to identify OSA. Aim of study To assess altered ventilatory response and heart rate recovery in response to exercise in patients with obstructive sleep apnea and their relation to its severity. Methods and Results Case control study was enrolled including 30 patients with obstructive sleep apnea (OSA) divided according to severity (5 mild, 8 moderate and 17 severe) and 15 control healthy overweight with sedentary lifestyle individuals. The two groups underwent cardiopulmonary exercise testing and different pulmonary and cardiac parameters were calculated. Greater VE, VE/VCO2, VE/VO2 ratios and VE/VCO2 slope were statistically significant regarding the patients group (P &amp;lt; 0.001, F = 69.053, 104.381, 140.806 and 68.010 respectively according to ANOVA test). OSA patients had a reduced maximal exercise capacity expressed as lower VO2 peak, decreased breathing reserve (BR) and VO2 at anaerobic threshold compared to control group (P &amp;lt; 0.001, F = 22.597, 68.773 and 82.90 respectively). Delayed heart rate recovery (HRR) and weaker chronotropic response (CR) in patients with OSA than in controls with negative relationship to severity of OSA were proved (p &amp;lt; 0.001, F = 119.493 and 91.271 respectively). The study revealed elevated maximal systolic BP (max SBP), diastolic BP (max DBP) and recovery SBP in the following 2 minutes after exercise in patients with OSA relative to their healthy controls with positive relationship to the severity of OSA (P &amp;lt; 0.001, F = 37.129, 169.275 and 244.609 respectively). Conclusion Patients with OSA demonstrated exaggerated ventilatory response to exercise and autonomic dysfunction reflected by measurement of heart rate variability and reduced maximal exercise capacity than healthy controls. Abbreviations OSA, CHF, CPXT, VO2, VCO2, VE, VE/VCO2, VE/VO2, VE/VCO2, BR, CR, HRR, max SBP and max DBP.

Relationships between parameters of cardiorespiratory function and bioimpedance analysis in young patients with type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) triggers disruption of oxygen transport system in patients. The maximum oxygen consumption (VO2 max) during spiroergometry depends on the functional capabilities and composition of the body. Moreover, VO2 max may be considered a predictor of pathological changes in cardiovascular system.Aim. The purpose of the study was to investigate the compositional body characteristics and functional cardiorespiratory parameters in T1DM patients.Material and Methods. The study comprised 30 patients with T1DM (average age of 25.5 ± 8.1 years) and 10 patients of control group (average age of 27 ± 9 years). Patients received spiroergometry examination according to B. Bruce protocol and bioimpedansometry using the Inbody 770 apparatus. The study showed that T1DM patients reached anaerobic threshold faster (p = 0.032) and had significantly lower VO2 max and carbon dioxide emission compared to patients without diabetes (p = 0.021; p = 0.034) whereas exercise tolerance did not significantly differ compared with the corresponding value in control group. Patients with higher muscle mass i.e. muscle tissue weight (kg) according to bioimpedance measurements had higher values of VO2 max (L) in control group (p = 0.017) and in group of T1DM patients (p = 0.028).Conclusions: Young T1DM patients without cardiovascular diseases had significantly less effective cardiorespiratory system compared with that in people without diabetes even in those with high exercise tolerance. Rapid achievement of anaerobic threshold with preserved performance efficiency was a sign of unfavorable prognosis. Body mass index and lean body mass did not significantly affect the performance parameters in young T1DM patients. Screening of spiroergometry parameters may be used for identification of young T1DM patients at high risk of unfavorable cardiovascular diseases including chronic heart failure.