Oxygen Uptake Efficiency Research Articles

Two-minute exercise testing is sufficient to estimate maximal cardiorespiratory fitness in people with epilepsy

We aimed to examine the agreement between submaximal cardiopulmonary exercise testing (CPET) measures and peak oxygen consumption (VO2peak) in adults with epilepsy. Data from a randomized controlled trial with adults with epilepsy (N = 21) were analyzed. VO2peak was assessed using indirect calorimetry during a treadmill graded maximal CPET. Oxygen uptake efficiency slope (OUES) was calculated from the relationship between oxygen uptake and minute ventilation during the entire test (OUESpeak) and the first 2 (OUES2min), 3 (OUES3min), and 4 (OUES4min) minutes of the CPET. The strength of the association between measures was tested by Pearson correlation. Linear regression models were used to predict VO2peak based on OUES from the different testing durations. Agreement between measured and predicted maximal values was tested using intraclass correlation coefficient (ICC) and Bland-Altman plots. OUES2min, OUES3min, and OUES4min were highly associated with absolute (r = 0.84, r = 0.76, r = 0.75, respectively) and relative (r = 0.84, r = 0.78, r = 0.78, respectively) VO2peak. Agreement (ICC = 0.83) between CPET-measured and OUES-predicted VO2peak values was stronger with OUES2min than the other time-based OUES markers. Bland-Altman plot showed satisfactory agreement between predicted and measured CPET measures with the narrowest limits of agreement observed with the OUES2min. No potential bias was identified between these two measurements (p = 0.33). Changes in absolute (r = 0.77) and relative (r = 0.88) VO2peak were highly associated with the change in OUES2min. OUES2min can be used as a surrogate for maximal cardiorespiratory fitness in adults with epilepsy. Studies with larger samples size are encouraged to confirm our findings in a more heterogeneous population.

Comparing individual and population differences in minute ventilation/carbon dioxide production slopes using centile growth curves and log-linear allometry.

Identifying vulnerable groups and/or individuals’ cardiorespiratory fitness (CRF) is an important challenge for clinicians/researchers alike. To quantify CRF accurately, the assessment of several variables is now standard practice including maximal oxygen uptake (VʹCO2) and ventilatory efficiency, the latter assessed using the minute ventilation/carbon dioxide production (VʹE/VʹCO2) slope. Recently, reference values (centiles) for VʹE/VʹCO2 slopes for males and females aged 20 to 80 have been published, using cardiopulmonary exercise testing (CPX) data (treadmill protocol) from the Fitness Registry and the Importance of Exercise National Database (FRIEND Registry).In the current observational study we provide centile curves for the FRIEND Registry VʹE/VʹCO2 slopes, fitted using the generalised additive model for location, scale and shape (GAMLSS), to provide individuals with a more precise estimate of where their VʹE/VʹCO2 slopes fall within the population. We also confirm that by adopting allometric models (incorporating a log transformation), the resulting ANCOVAs provided more normal and homoscedastic residuals, with superior goodness-of-fit using the Akaike information criterion (AIC)=14 671 (compared with traditional ANCOVA's AIC=15 008) that confirms allometric models are vastly superior to traditional ANCOVA models.In conclusion, providing sex-by-age centile curves rather than referring to reference tables for ventilatory efficiency (VʹE/VʹCO2 slopes) will provide more accurate estimates of where an individual's particular VʹE/VʹCO2 slope falls within the population. Also, by adopting allometric models researchers are more likely to identify real and valid inferences when analysing population/group differences in VʹE/VʹCO2 slopes.

Heritable variation in swimming performance in Nile tilapia (Oreochromis niloticus) and negative genetic correlations with growth and harvest weight

Nile tilapia is predominantly produced in smallholder ponds without aeration. We hypothesize that Nile tilapia with high oxygen uptake efficiency (O2UE) may perform better under these conditions than Nile tilapia with low O2UE. Critical swimming speed (Ucrit, in cm s−1) is a potential indicator for O2UE. Our objectives were to estimate variance components for Ucrit and fish size at swim testing early in life, and genetic correlations (rg) between Ucrit with harvest weight (HW) and daily growth coefficient (DGC) later after grow-out in a non-aerated pond. Substantial heritability was found for absolute Ucrit (0.48). The estimated rg between absolute Ucrit and fish size at testing were all strong and positive (range 0.72–0.83). The estimated rg between absolute Ucrit and HW, and absolute Ucrit and DGC were − 0.21 and − 0.63 respectively, indicating that fish with higher absolute Ucrit had lower growth in the non-aerated pond as compared to fish with lower absolute Ucrit. These results suggest a juvenile trade-off between swimming and growth performance where fish with high Ucrit early in life show slower growth later under conditions of limited oxygen availability. We conclude that Ucrit in Nile tilapia is heritable and can be used to predict growth performance.

Neuromuscular electrical stimulation resistance training enhances oxygen uptake and ventilatory efficiency independent of mitochondrial complexes after spinal cord injury: a randomized clinical trial.

The purpose of the study was to determine whether neuromuscular electrical stimulation resistance training (NMES-RT)-evoked muscle hypertrophy is accompanied by increased V̇o2 peak, ventilatory efficiency, and mitochondrial respiration in individuals with chronic spinal cord injury (SCI). Thirty-three men and women with chronic, predominantly traumatic SCI were randomized to either NMES-RT (n = 20) or passive movement training (PMT; n = 13). Functional electrical stimulation-lower extremity cycling (FES-LEC) was used to test the leg V̇o2 peak, V̇E/V̇co2 ratio, and substrate utilization pre- and postintervention. Magnetic resonance imaging was used to measure muscle cross-sectional area (CSA). Finally, muscle biopsy was performed to measure mitochondrial complexes and respiration. The NMES-RT group showed a significant increase in postintervention V̇o2 peak compared with baseline (ΔV̇o2 = 14%, P < 0.01) with no changes in the PMT group (ΔV̇o2 = 1.6%, P = 0.47). Similarly, thigh (ΔCSAthigh = 19%) and knee extensor (ΔCSAknee = 30.4%, P < 0.01) CSAs increased following NMES-RT but not after PMT. The changes in thigh and knee extensor muscle CSAs were positively related with the change in V̇o2 peak. Neither NMES-RT nor PMT changed mitochondrial complex tissue levels; however, changes in peak V̇o2 were related to complex I. In conclusion, in persons with SCI, NMES-RT-induced skeletal muscle hypertrophy was accompanied by increased peak V̇o2 consumption which may partially be explained by enhanced activity of mitochondrial complex I.NEW & NOTEWORTHY Leg oxygen uptake (V̇o2) and ventilatory efficiency (V̇E/V̇co2 ratio) were measured during functional electrical stimulation cycling testing following 12-16 wk of either electrically evoked resistance training or passive movement training, and the respiration of mitochondrial complexes. Resistance training increased thigh muscle area and leg V̇o2 peak but decreased V̇E/V̇co2 ratio without changes in mitochondrial complex levels. Leg V̇o2 peak was associated with muscle hypertrophy and mitochondrial respiration of complex I following training.

Exploring the physiological determinants of marathon performance

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ESPA 2014-2020 Background/Introduction: Long-time endurance exercise training leads to cardiovascular, respiratory, haematological and neuromuscular adaptations. The relative contribution of these adaptations to running performance in long-distance races remains to be elucidated in an integrative manner. Purpose The study of the relationship of marathon performance with anthropometric, cardiorespiratory and haematological adaptations. Methods Thirty-one marathon runners (26 males, age: 42 ± 9 years) were examined within 3 weeks before Athens marathon race (42.195 km). Assessment of training characteristics, anthropometric measurements, including height, body weight and body fat percentage, echocardiographic study, cardiopulmonary exercise testing using treadmill ergometer and blood test were performed. Results Training age was 11(1-39) years. Body fat percentage(BFP) was 17.3 ± 7.1% and body weight-indexed maximum oxygen uptake(VO2max) was 52.6 ± 8.9 mL/kg/min. Marathon race time(MRT) was 3:59:01(2:47:17-5:31:32). Among anthropometric measurements, MRT was positively associated with BFP(r= 0.561, p = 0.002) and body fat mass(r = 0.514, p = 0.005), even after adjustment for VO2max or oxygen uptake at first(VO2-VT1) or second(VO2-VT2) ventilatory threshold, implying an effect of BFP on running economy. Among echocardiographic parameters, MRT correlated negatively with right ventricular end-diastolic area(RVEDA) (r = -0.707, p &amp;lt; 0.001) and ratio of early to late diastolic transtricuspid flow velocity(TVE/A) (r= -0.430, p = 0.025). MRT correlated negatively with body weight-indexed VO2max (r= -0.692, p &amp;lt; 0.001), VO2-VT1 (r= -0.426, p = 0.019) and VO2-VT2 (r= -0.688, p &amp;lt; 0.001). MRT correlated negatively with maximum minute ventilation(VEmax) (r= -0.418, p = 0.022), VEmax indexed for body surface area(BSA) (r= -0.456, p= 0.011), maximum tidal volume(Vtmax) indexed for BSA(r= -0.436, p = 0.018) and oxygen uptake efficiency slope(OUES) (r= -0.529, p = 0.003). MRT was not associated with haemoglobin concentration. RVEDA correlated positively with maximum oxygen pulse (r = 0.653, p = 0.001), which is an estimate of stroke volume during exercise, and OUES(r = 0.534, p = 0.009). After performing multivariate linear regression analysis with MRT as dependent variable and BFP(standardized β=0.495, p = 0.001), RVEDA(standardized β= -0.550, p = 0.001) and Vtmax indexed for BSA(standardized β= -0.110, p = 0.418) as independent variables, only BFP and RVEDA were significant independent predictors of MRT(adjusted R2 = 0.667, p &amp;lt; 0.001 for the model). Conclusions The results of the present study demonstrated that the main cardiorespiratory adaptation that could predict a better marathon performance was right ventricular dilatation, through the increase in stroke volume during exercise, whereas upregulation of tidal volume during exercise was found to be a weaker predictor. The principal anthropometric determinant of marathon performance appears to be body fat percentage, via the influence on running economy. Abstract Figure 1

Oxygen uptake efficiency slope: A submaximal test evaluation tool that provides cardiopulmonary reserve data in individuals with Parkinson's disease

BackgroundOxygen uptake efficiency slope (OUES) is a method for investigating cardiorespiratory fitness and is proposed as an alternative to overcome the limitations of traditional measures such as peak oxygen consumption (VO2peak) for patients who do not achieve a maximum response, such as in Parkinson's disease (PD). ObjectiveTo assess the performance of individuals with PD during the six-minute walk test (6MWT) using the OUES. MethodsThis is an observational cross-sectional study including 12 individuals with PD and 12 healthy controls. Participants performed the 6MWT along with an analysis of exhaled gas kinetics. The OUES was determined from the last 16 s of the walk test. Multiple linear regression analyses were computed to explore associations between the independent (OUES) and the dependent variables (VO2peak) controlled by group. ResultsThe OUES was associated to VO2peak on the 6MWT (β=0.24, p<0.01) in individuals with PD. The PD group had low performance on the 6MWT with a shorter distance walked (mean difference: -113.1 m; 95% CI: -203.2, -59.1) and worse cardiopulmonary condition with lower OUES values (mean difference: -0.52 [l/minO2]/[l/minVE]; 95% CI: -0.83, -0.21) found in this same group. ConclusionsOur results suggest that OUES is related to VO2peak during the 6MWT, and therefore it could be used as a submaximal test evaluation tool which provides cardiopulmonary reserve data in individuals with PD.

Physiological Factors Important to Cardiorespiratory Fitness are Similar Between Breast Cancer Survivors and Controls

Rationale Breast cancer is the most common type of cancer in the United States, and breast cancer survivors have a high prevalence of cardiovascular disease (CVD) and reduced cardiorespiratory fitness. Cardiorespiratory fitness is a major predictor of CVD and all-cause mortality in the general population, and an important predictor of survival in breast cancer survivors. However, the physiological factors that contribute to reduced cardiorespiratory fitness in breast cancer survivors have not been completely elucidated. Purpose To assess differences in cardiorespiratory fitness and physiological factors (cardiac, pulmonary, and muscle oxygenation) between breast cancer survivors and age and BMI-matched control groups. Methods To examine this, 23 female breast cancer survivors (50 ± 9 yrs; 25.5 ± 2.9 kg/m2), and 23 female age and BMI-matched controls (49 ± 9 yrs; 25.7 ± 4.6 kg/m2), underwent a maximal exercise test on a cycle ergometer with cardiac function, pulmonary function, and muscle oxygenation evaluated at baseline and at peak exercise (VO2peak). Cardiac variables included stroke volume (SV), heart rate (HR), and cardiac output (Q). SV was assessed from aortic blood flow waveforms (3 cardiac cycles) obtained via Doppler echocardiography using a pedoff probe placed on the suprasternal notch. SV was calculated as = π × (LVOT2/2) × VTI, where LVOT = left ventricular outflow tract diameter and VTI = subvalvular velocity time integral. Q was calculated as SV × HR. Both SV and Q were indexed to body surface area. Pulmonary function variables included the oxygen uptake efficiency slope (OUES) and ventilation to carbon dioxide production slope (VE/VCO2 slope)) acquired from indirect calorimetry during the peak cycling exercise test. Muscle oxygenation variables (oxygenated (HbO2), deoxygenated (HHb) and total hemoglobin (Hb), and tissue saturation index (TSI)) were measured non-invasively with near-infrared spectroscopy (NIRS) from the rectus femoris. Results VO2peak was similar between groups. Both groups similarly increased all cardiac variables (HR, SV, SVindex, Q, and Qindex) at peak exercise compared to baseline (p<0.001). Breast cancer survivors, however, had higher HR and lower SVindex values (group effect, p<0.05). Breast cancer survivors also had similar OUES and VE/VCO2 slope values compared to the control group. TSI decreased and Hb and HHb increased at peak exercise compared baseline (p<0.001), with similar responses observed in both groups. Conclusion: Our data suggest breast cancer survivors do not exhibit differences in cardiac, pulmonary, and muscle function variables at peak exercise compared to controls, when both groups have similar cardiorespiratory fitness. It appears cardiorespiratory fitness may not be as consistently attenuated in breast cancer survivors as previously reported in the literature, and warrants further examination.

A clinical evaluation of VO2 kinetics in kidney transplant recipients

PurposeAerobic exercise capacity is reduced in patients with chronic kidney disease, partly due to alterations at the muscular and microvascular level. This study evaluated oxygen uptake (VO2) kinetics as indicator of muscular oxidative metabolism in a population of Kidney Transplant Recipients (KTRs).MethodsTwo groups of KTRs enrolled 3 (n = 21) and 12 months (n = 14) after transplantation and a control group of healthy young adults (n = 16) underwent cardiopulmonary exercise testing on cycle-ergometer. The protocol consisted in two subsequent constant, moderate-load exercise phases with a final incremental test until exhaustion.ResultsThe time constant of VO2 kinetics was slower in KTRs at 3 and 12 months after transplantation compared to controls (50.4 ± 13.1 s and 43.8 ± 11.6 s vs 28.9 ± 8.4 s, respectively; P < 0.01). Peak VO2 was lower in KTRs evaluated 3 months after transplantation compared to patients evaluated after 1 year (21.3 ± 4.3 and 26.4 ± 8.0 mL/kg/min; P = 0.04). Blood haemoglobin (Hb) concentration was higher in KTRs evaluated at 12 months (12.8 ± 1.7 vs 14.6 ± 1.7 g/dL; P < 0.01). Among KTRs, τ showed a moderate negative correlation with Peak VO2 (ρ = − 0.52) and Oxygen uptake efficiency slope (OUES) (r = − 0.57) while no significant correlation with Hb and peak heart rate.ConclusionsKTRs show slower VO2 kinetics compared to healthy controls. Hb and peak VO2 seem to improve during the first year after transplantation. VO2 kinetics were significantly associated with indices of cardiorespiratory fitness, but less with central determinants of aerobic capacity, thus suggesting a potential usefulness of adding this index of muscular oxidative metabolism to functional evaluation in KTRs.

The Relationship between Resistance Exercise Performance and Ventilatory Efficiency after Beetroot Juice Intake in Well-Trained Athletes.

The assessment of ventilatory efficiency is critical to understanding the matching of ventilation (VE) and perfusion in the lungs during exercise. This study aimed to establish a causal physiological relationship between ventilatory efficiency and resistance exercise performance after beetroot juice (BJ) intake. Eleven well-trained males performed a resistance exercise test after drinking 140 mL of BJ (~12.8 mmol NO3−) or a placebo (PL). Ventilatory efficiency was assessed by the VE•VCO2−1 slope, the oxygen uptake efficiency slope and the partial pressure of end-tidal carbon dioxide (PetCO2). The two experimental conditions were controlled using a randomized, double-blind crossover design. The resistance exercise test involved repeating the same routine twice, which consisted of wall ball shots plus a full squat (FS) with a 3 min rest or without a rest between the two exercises. A higher weight lifted was detected in the FS exercise after BJ intake compared with the PL during the first routine (p = 0.004). BJ improved the VE•VCO2−1 slope and the PetCO2 during the FS exercise in the first routine and at rest (p < 0.05). BJ intake improved the VE•VCO2−1 slope and the PetCO2 coinciding with the resistance exercise performance. The ergogenic effect of BJ could be induced under aerobic conditions at rest.

Peripheral Oxygen Extraction and Exercise Limitation in Asymptomatic Patients with Diabetes Mellitus

Patients with diabetes mellitus (DM) frequently present reduced exercise capacity. We aimed to explore the extent to which peripheral extraction relates to exercise capacity in asymptomatic patients with DM. We prospectively enrolled 98 asymptomatic patients with type-2 DM (mean age of 59 ± 11 years and 56% male sex), and compared with 31 age, sex and body mass index-matched normoglycemic controls. Cardiopulmonary exercise testing with resting followed by stress echocardiography was performed. Exercise response was assessed using peak oxygen uptake (peak VO2) and ventilatory efficiency was measured using the slope of the relationship between minute ventilation and carbon dioxide production (VE/VCO2). Peripheral extraction was calculated as the ratio of VO2 to cardiac output. Cardiac function was evaluated using left ventricular longitudinal strain, E/e', and relative wall thickness. Among patients with DM, 26 patients (27%) presented reduced percent-predicted-peak VO2(<80%) and 18 (18%) presented abnormal VE/VCO2slope (>34). There was no significant difference in peak cardiac output; however, peripheral extraction was lower in patients with DM compared to controls. Higher peak E/e' (beta = -0.24, p = 0.004) was associated with lower peak VO2 along with age, sex and body mass index (R2 = 0.53). A cluster analysis found left ventricular longitudinal strain, E/e', relative wall thickness and peak VO2 in different clusters. In conclusion, impaired peripheral extraction may contribute to reduced peak VO2in asymptomatic patients with DM. Furthermore, a cluster analysis suggests that cardiopulmonary exercise testing and echocardiography may be complementary for defining subclinical heart failure in patients with DM.

Prognostic Value of Cardiopulmonary Exercise Test Parameters in Ventricular Assist Device Therapy

<h3>Purpose</h3> Cardiopulmonary exercise test parameters are among the best prognosticators for medically managed advanced heart failure. However, the prognostic value of pre & post-implantation CPET parameters in LVAD therapy is unclear and is evaluated in this study. <h3>Methods</h3> Adult patients who were implanted with an LVAD and underwent CPET during the pre and/or post-implantation period were included to the study. Five parameters were derived from each CPET: vO₂max, oxygen uptake efficiency slope (OUES), vE/vCO₂min, vE/vCO₂max and vE/vCO₂ Slope. The independent predictive relationship between CPET parameters and clinical outcomes was evaluated with multivariate analysis. <h3>Results</h3> Pre & post-implantation CPET cohorts included 191 and 122 patients respectively (Table 1). Among pre-implantation CPET parameters: vO₂max was an independent predictor of in-hospital mortality; vO₂max and OUES were independent predictors of 1-year, 3-year and 5-year mortality, whereas vE/vCO₂min and vE/vCO₂ Slope were independent predictors of 5-year mortality (p<.05). No CPET parameter was associated with ICU or hospital length of stay, 30-day readmission or 90-day mortality (p>.05). Among post-implantation CPET parameters: vO₂max was an independent predictor of 5-year mortality, while vE/vCO₂min and vE/vCO₂max were independent predictors of 3-year mortality (p<.05) (Table 2). <h3>Conclusion</h3> CPET parameters derived from pre and post-implantation exercise tests have high predictive value for long-term outcomes in LVAD therapy. Except vO₂max, CPET parameters' predictive capacity for early post-implantation outcomes appears to be limited.

A novel exercise testing algorithm to diagnose mitochondrial myopathy.

Oxygen uptake efficiency slope (OUES) is a noninvasive cardiopulmonary exercise testing (CPET) measurement based on oxygen uptake (V˙O2 ) and minute ventilation (V˙E) and is a marker of the efficiency of oxygen utilization by the body. However, it has not been studied in mitochondrial disorders. We explored noninvasive CPET parameters, including OUES, as a way to reliably diagnose mitochondrial myopathy. We performed cycle ergometer maximal exercise testing on definite and suspected mitochondrial myopathy subjects (MM-D and MM-S) and their age- and sex-matched controls. OUES was corrected for body surface area (OUES/BSA) to eliminate the effect of body size. A total of 40 participants, including 20 MM-D (n = 13; 6 males; aged 14-64 years) and 7 MM-S (5 males, aged 11-30 years) subjects and 20 controls, completed the study. MM-D subjects showed lower aerobic fitness than controls. OUES/BSA was lower in MM-D subjects, suggesting inefficient oxygen utilization. Area under the curve (AUC) and 95% confidence interval (CI) for OUES/BSA (AUC, 0.91; 95% CI, 0.80-1.00), peak V˙O2 percent predicted (AUC, 0.95; 95% CI, 0.86-1.00), and V˙O2 /work slope (AUC, 0.94; 95% CI, 0.85-1.00) showed excellent ability to diagnose mitochondrial myopathy in MM-D subjects. We applied a diagnostic approach based on the parameters just noted to MM-S subjects and their controls and were able to support or disprove the diagnosis of mitochondrial myopathy. We proposed and applied an approach based on the aformentioned three CPET parameters to diagnose mitochondrial myopathy reliably and found it to be clinically useful.

Cardiopulmonary exercise testing was used to evaluate objectively and quantitatively the holistic function in patients after neoadjuvant chemotherapy

Objective: Cardiopulmonary exercise testing(CPET)was used to evaluate objectively and quantitatively the holistic function in patients accepted preoperative chemotherapy. Methods: This study investigated reliable objective and quantitative assessment methods of symptom limited maximal incremental CPET before and after chemotherapy in patients with 6 esophageal cancer. We re-analyzed the changes in cardiopulmonary, metabolism, and other functions physiologic parameters of CPET. Results: After patients accepted preoperative chemotherapy,Peak oxygen consumption (Peak VO2)(P<0.05), anaerobic threshold (AT) and peak oxygen pulse (Peak O2 paulse), oxygen uptake efficiency plateau (OUEP)were decreased (P<0.01). The lowest of ventilatory equivalent for carbon dioxide and slope of ventilatory equivalent for carbon dioxide were increased (P<0.05). For individual of all patients, except one patient's Peak VO2 and OUEP slightly increased,all of the above indicators were reduced in the remaining patients. The lowest of ventilatory equivalent for carbon dioxide and slope of ventilatory equivalent for carbon dioxide increased in all the patients,except one patient's slope of ventilatory equivalent for carbon dioxide decreased slightly. The heart rate of 6 patients showed an upward trend in each state, but there was no statistical difference. Three of the 6 patients had blood pressure measurement, and the other 3 patients had a significant decrease in diastolic blood pressure (P<0.05) except at extreme state.The patients had lower oxygen uptake at AT(P<0. 01) and extreme state (P<0. 05) than that before chemotherapy. The oxygen uptake efficiency in a warm-up state(P<0. 01),and an AT state(P<0. 05)after chemotherapy were lower than those before chemotherapy. The ventilator equivalent for carbon dioxide after chemotherapy was in the each states presented an upward trend, but only ventilator equivalent for carbon dioxide after in the warm-up state (P<0.05) and AT(P<0.01) had statistical significance. oxygen pulse in all four states showed a decreasing trend, and only at AT (P<0.05) showed a significant decrease.After chemotherapy,the PETCO2 in a warm-up state after chemotherapy was lower than that before chemotherapy(P<0. 05); the PETO2 in a quiescent state,a warm - up state,and an extreme state after chemotherapy were higher than those before chemotherapy;but there was nosignificant difference. Conclusion: The holistic functional capacity of patients with esophageal significantly decreased after 136 days chemotherapy. The circulatory functionalandentilator functional parameters significantly decreased after chemotherapy.

A clinical research report on the pathophysiological characteristics of exercise in patients with mitral regurgitation

Objective: Cardiopulmonary exercise testing (CPET) was used to investigate the exercise pathophysiology of mitral regurgitation. Methods: 26 patients with moderate and severe mitral regurgitation who completed standardized extreme exercise CPET under strict quality control after signing informed consent since 2016, and 11 normal subjects in the same period as the control group. The core indexes of CPET were analyzed and calculated according to the standard method and compared with normal subjects for intergroup statistical independent sample t-test. At the same time, the patients with heart failure and exercise oscillation breathing (OB) were divided into two subgroups: 11 cases without heart failure, 15 cases with heart failure, 8 cases with non-OB and 18 cases with OB, and their similarities and differences were compared between each subgroup. Results: The core indexes of CPET, such as peak oxygen uptake (85.60 ±9.06)%pred and anaerobic threshold (AT, (87.59 ±15.38)%pred) were normal. The peak oxygen uptake of CPET in patients with mitral regurgitation was (48.15 ±12.11)%pred, peak oxygen pulse was (66.57 ±12.20)%pred, AT was (56.75 ±11.50)%pred, oxygen uptake efficiency plateau was (88.24 ±16.42)%pred , lowest value of carbon dioxide ventilatory efficiency was (125.89 ±27.05)%pred and slope of carbon dioxide ventilatory efficiency was (128.31 ±31.68)%pred. Among them, only oxygen uptake efficiency plateau (OUEP) was normal and low, and the other indexes were significantly abnormal. There were significant differences between the patients and the control group (P<0.01). There was no significant difference between the non-OB group and the OB group, but there was significant difference between the non-OB group and the control group (P<0.05). There was no significant difference between the non-heart failure group and the heart failure group, but there was significant difference between the non-heart failure group and the control group. Conclusion: All the core indexes of cardiopulmonary exercise are significantly abnormal in patients with mitral regurgitation who are significantly lower than those in normal subjects except for the low effectiveness of oxygen ventilation. And with or without heart failure and OB did not affect the cardiopulmonary function.

Clinical study on the characteristics of exercise pathophysiological in patients with severe heart failure

Objective: The cardiopulmonary function of patients with chronic heart failure (CHF) was severely limited, but the holistic integrative exercise pathophysiology is still unclear. Methods: After signed the consent form, Eighty three patients with severe CHF from October 2016 to October 2017 in Fuwai Hospital were performed Ramp incremental loading program CardioPulmonary Exercise Testing (CPET), and 12 normal subjects served as control. CPET were performed according to standard of Harbor-UCLA MC and the circulatory, respiratory and metabolic parameters during CPET were measured and analyzed. Results: Peak oxygen uptake (Peak VO2) in CHF (14.33±2.69) ml/(min·kg), (44.25±14.74)%pred was significantly lower than control ((29.42±5.46) ml/(min·kg), (83.88±6.28)%pred). Other core parameters of CPET such as anaerobic threshold (AT), peak oxygen pulse, oxygen uptake efficiency platform (OUEP), the lowest of carbon dioxide output ventilation ratio (Lowest VE/VCO2), and carbon dioxide output ventilation slope (VE/VCO2 Slope) in CHF were significantly different with the control group(P<0.01). The core parameters of lung function, such as forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, and carbon monoxide diffusion (DLCO) were significantly decreased (P<0.01). Systolic blood pressure during all stages of CPET in CHF was significantly lower than control group (P<0.05); Heart rate at AT, peak and recovery stages were significantly lower than control (P<0.01). Minute ventilation, tidal volume and respiratory frequency at rest, warm-up were significantly higher than control (P<0.05). Tidal volume at recovery was significantly higher than control (P<0.05). VO2 at AT, peak and recovery stages in CHF were significantly higher than control (P<0.01). Oxygen pulse at AT and peak were significantly higher than control (P<0.01). Pulse oxygen saturation during all stages of CPET in CHF were significantly lower than control (P<0.01). Conclusion: The decreased holistic functional capacity of cardiogenic CHF dominantly due to circulatory limitation, and secondly due to respiratory and metabolic limitation.

Predictive Value of Cardiopulmonary Exercise Testing Parameters in Ambulatory Advanced Heart Failure

ObjectivesThis study sought to determine cardiopulmonary exercise (CPX) predictors of the combined outcome of durable mechanical circulatory support (MCS), transplantation, or death at 1 year among patients with ambulatory advanced heart failure (HF). BackgroundOptimal CPX predictors of outcomes in contemporary ambulatory advanced HF patients are unclear. MethodsREVIVAL (Registry Evaluation of Vital Information for ventricular assist devices [VADs] in Ambulatory Life) enrolled 400 systolic HF patients, INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profiles 4-7. CPX was performed by 273 subjects 2 ± 1 months after study enrollment. Discriminative power of maximal (peak oxygen consumption [peak VO2]; VO2 pulse, circulatory power [CP]; peak systolic blood pressure • peak VO2], peak end-tidal pressure CO2 [PEtCO2], and peak Borg scale score) and submaximal CPX parameters (ventilatory efficiency [VE/VCO2 slope]; VO2 at anaerobic threshold [VO2AT]; and oxygen uptake efficiency slope [OUES]) to predict the composite outcome were assessed by univariate and multivariate Cox regression and Harrell’s concordance statistic. ResultsAt 1 year, there were 39 events (6 transplants, 15 deaths, 18 MCS implantations). Peak VO2, VO2AT, OUES, peak PEtCO2, and CP were higher in the no-event group (all p < 0.001), whereas VE/VCO2 slope was lower (p < 0.0001); respiratory exchange ratio was not different. CP (hazard ratio [HR]: 0.89; p = 0.001), VE/VCO2 slope (HR: 1.05; p = 0.001), and peak Borg scale score (HR: 1.20; p = 0.005) were significant predictors on multivariate analysis (model C-statistic: 0.80). ConclusionsAmong patients with ambulatory advanced HF, the strongest maximal and submaximal CPX predictor of MCS implantation, transplantation, or death at 1 year were CP and VE/VCO2, respectively. The patient-reported measure of exercise effort (Borg scale score) contributed substantially to the prediction of outcomes, a surprising and novel finding that warrants further investigation. (Registry Evaluation of Vital Information for VADs in Ambulatory Life [REVIVAL]; NCT01369407)

Effect of a 7-week low intensity synchronous handcycling training programme on physical capacity in abled-bodied women

ABSTRACT This study evaluated the effect of a low-intensity norm duration synchronous handcycle wheelchair training in untrained able-bodied women. The training group (n = 9) received 7-weeks of low-intensity upper body training in an instrumented handcycle on a motor-driven treadmill (MDT), 3 × 30 min/week at 30% heart rate reserve. The control group (n = 10) received no training. Incremental handcycle tests on the MDT were used to determine peak values for oxygen uptake (VO2peak), power output (POpeak), heart rate (HRpeak), minute ventilation (VEpeak), and respiratory exchange ratio (RERpeak), submaximal values for heart rate (HR), oxygen uptake (VO2) and gross efficiency (GE) before and after training. Local perceived discomfort and rate of perceived exertion (RPE) were also assessed. Training significantly improved POpeak (+20%), HRpeak (+3%), RERpeak (+5%), submaximal GE (+21%), VO2 (−20%), VE (−33%), HR (−12%) and RPE was low (7.1 ± 0.5) (p < 0.05). No effects were found in VO2peak and VEpeak (p > 0.05). Though VO2peak did not improve, low-intensity norm duration handcycling training improved handcycling POpeak, while RPE was low. Also, GE increased, suggesting a motor control improvement. Handcycle training seems to be an appropriate exercise mode to improve physical capacity, and prevent early fatigue and overuse in untrained individuals.

Oxygen Uptake Efficiency Slope is Strongly Correlated to VO2peak Long-Term After Arterial Switch Operation

After the arterial switch operation (ASO) for transposition of the great arteries (TGA), many patients have an impaired exercise tolerance. Exercise tolerance is determined with cardiopulmonary exercise testing by peak oxygen uptake (VO2peak). Unlike VO2peak, the oxygen uptake efficiency slope (OUES) does not require a maximal effort for interpretation. The value of OUES has not been assessed in a large group of patients after ASO. The purpose of this study was to determine OUES and VO2peak, evaluate its interrelationship and assess whether exercise tolerance is related to ventricular function after ASO. A cardiopulmonary exercise testing, assessment of physical activity score and transthoracic echocardiography (fractional shortening and left/right ventricular global longitudinal peak strain) were performed to 48 patients after ASO. Median age at follow-up after ASO was 16.0 (IQR 13.0–18.0) years. Shortening fraction was normal (36 ± 6%). Left and right global longitudinal peak strain were reduced: 15.1 ± 2.4% and 19.5 ± 4.5%. This group of patients showed lower values for all cardiopulmonary exercise testing parameters compared to the reference values: mean VO2peak% 75% (95% CI 72–77) and mean OUES% 82(95% CI 77–87); without significant differences between subtypes of TGA. A strong-to-excellent correlation between the VO2peak and OUES was found (absolute values: R = 0.90, p < 0.001; normalized values: R = 0.79, p < 0.001). No correlation was found between cardiopulmonary exercise testing results and left ventricle function parameters. In conclusion, OUES and VO2peak were lower in patients after ASO compared to reference values but are strongly correlated, making OUES a valuable tool to use in this patient group when maximal effort is not achievable.

Factors related to the discontinuation and mortality rates of a cardiac rehabilitation programme in patients with Chagas disease: a 6-year experience in a Brazilian tertiary centre.

To describe the clinical and sociodemographic characteristics of participants as well as discontinuation and mortality rates in a cardiac rehabilitation programme (CRP) tailored to Chagas disease (CD). Participants underwent functional capacity, anthropometry and cardiac function evaluations before beginning a CRP. Univariate and multivariate Cox proportional hazards models were performed to investigate the associations between clinical and sociodemographic characteristics at baseline with discontinuation rates and deaths. Forty-two patients were enrolled in the CRP (61.9% men, mean age of 58.1±11.8years). During a median follow-up period of 10.8months, 74% discontinued and 14% died while enrolled in CRP. 34% of the patients who discontinued CRP died during follow-up. White race (HR=0.09; 95% CI 0.01-1.00), right ventricular systolic dysfunction (HR=10.54; 95% CI 1.24-89.50) and oxygen pulse (HR=0.69; 95% CI 0.48-0.99) were independently associated with death while enrolled in CRP. Married status (HR=0.44; 95% CI 0.21-0.95) was independently associated with discontinuation rates from CRP. VO2 peak (HR=0.85; 95% CI 0.74-0.98) and CRP discontinuation due to CD-related reasons (HR=8.33; 95% CI 1.91-36.27) were the variables independently associated with death after discontinuation of CRP. In this population, sociodemographic aspects and severity of CD were important determinants of CRP discontinuation and mortality.

Cardiopulmonary exercise testing (CPET)to evaluate the efficacy after intensive control of personalized precise exercise training for cardiovascular and cerebrovascular chronic diseases

Objective: To study the symptom-restricted extreme cardiopulmonary exercise testing (CPET) to evaluate the improvement of the overall function of patients with long-term chronic diseases after intensive control of personalized precise exercise training for 3 months. Methods: We selected 20 patients with chronic cardiovascular and cerebrovascular metabolic diseases who were intensively controlled by our team from 2014 to 2016. After signing the informed consent form, based on the results of CPET and continuous functional tests, we formulated the overall management plan with individualized moderate exercise intensity as the core. After 3 months, CPET was performed. The changes of CPET indicators before and after intensive control in each patient were analyzed individually. Then the difference value and percentage difference value were calculated. Results: In this study, 20 patients (18 males and 2 females) with chronic cardiovascular and cerebrovascular metabolic diseases, aged (55.75±10.80, 26~73) years, height (172.20±8.63, 153~190) cm, weight (76.35±15.63, 53~105) kg, all patients were not any dangerous events during the period of CPET and intensive control.①After intensive control, the static pulmonary function index, resting systolic blood pressure, rate blood pressure product and fasting blood glucose were significantly improved (P<0.05).②Before intensive control, the peak oxygen uptake is (55.60±15.69, 34.37~77.45) % pred and anaerobic threshold is (60.11±12.26, 43.29~80.63)% pred; after intensive control, the peak oxygen uptake is (71.85±21.04, 42.40~102.00) % pred and anaerobic threshold (74.95±17.03, 51.90~99.47) %pred. Compared with before the intensive control, the peak oxygen uptake and anaerobic threshold of all patients after intensive control were significantly increased by (29.09±7.38,17.78~41.80) % and(25.16±18.38, 1.77~81.86)%(all P<0.01). Other core indexes were also improved significantly, including peak oxygen uptake,peak heart rate, peak work rate, oxygen uptake efficiency plateau, lowest value of carbon dioxide ventilatory efficiency, slope of ventilatory equivalent for carbon dioxide, ramp exercise duration(all P<0.01).③In terms of individualized analysis, after intensive control, the above 8 CPET core indexes were all improved in 15 cases, and 7 indexes in 5 cases were improved; the peak oxygen uptakeof all cases increased by more than 15%, 16 cases > 20%, 13 cases > 25%, 10 cases > 30%. Conclusion: CPET can safely, objectively and quantitatively evaluate the overall functional status and therapeutic effects, and guide the formulation of individualized precise exercise intensity. The overall plan of individualized precision exercise for three months can safely and effectively reverse the overall functional status of patients with long-term cardio-cerebrovascular metabolism diseases.