Peak Exercise VO2 Research Articles

Cardiopulmonary Exercise Testing in Transgender and Gender-Diverse Patients: The Influence of Sex and Gender on Predicted Aerobic Capacity

BackgroundSex assigned at birth (SAB) is currently used to calculate predicted normative values for oxygen consumption (VO2) during cardiopulmonary exercise testing (CPET) in transgender and gender diverse (TGD) patients. It is unclear if this is physiologically valid once gender-affirming hormonal therapy (GAHT) has been instituted. Research QuestionWhat are the changes in functional aerobic capacity (FAC) and in percentage of predicted (%pred) peak VO2 when gender is used, instead of SAB, to estimated normative predicted values among TGD patients >14 years of age who are receiving GAHT? Study Design and MethodsWe retrospectively analyzed 16 referred TGD patients (8 transgender men, 8 transgender women) receiving GAHT therapy at the time of the test. Data collected and analyzed included: clinical indication for CPET, biometrics (age, height, and weight), CPET parameters (treadmill, Mayo Clinic protocol, without chest binder), chest imaging, echocardiographic results, and hemoglobin levels. ResultsIn transgender women, the use of gender congruent normative predictive values, instead of SAB, significantly increased FAC (69.70 ± 4.35 vs. 87.82 ± 5.15 [%]; mean ± SE; for SAB and gender, respectively; p= <0.0001) and %pred peak VO2 (66.53 ± 4.17 vs. 89.69 ± 5.60 [%]; mean ± SE; for SAB and gender, respectively; p= <0.0001). In transgender men, the use of gender congruent normative predictive values showed that both FAC and %pred peak VO2 significantly decreased (approximately 20% and 25%, respectively). Deconditioning was the most frequent CPET finding among transgender men. InterpretationAmong TGD individuals receiving GAHT, the use of gender to calculate normative values affects %pred peak exercise VO2 and FAC significantly. Body composition changes after GAHT require regular monitoring of muscle strength, lean body mass, and aerobic capacity. Cardiopulmonary symptoms among TGD patients should be assessed with these variables in mind –especially in the presence of chronic cardiac and pulmonary diseases.

Neurovascular Dysregulation and Acute Exercise Intolerance in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Placebo-Controlled Trial of Pyridostigmine

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by intractable fatigue, postexertional malaise, and orthostatic intolerance, but its pathophysiology is poorly understood. Pharmacologic cholinergic stimulation was used to test the hypothesis that neurovascular dysregulation underlies exercise intolerance in ME/CFS. Does neurovascular dysregulation contribute to exercise intolerance in ME/CFS, and can its treatment improve exercise capacity? Forty-five subjects with ME/CFS were enrolled in a single-center, randomized, double-blind, placebo-controlled trial. Subjects were assigned in a 1:1 ratio to receive a 60-mg dose of oral pyridostigmine or placebo after an invasive cardiopulmonary exercise test (iCPET). A second iCPET was performed 50min later. The primary end point was the difference in peak exercise oxygen uptake (Vo2). Secondary end points included exercise pulmonary and systemic hemodynamics and gas exchange. Twenty-three subjects were assigned to receive pyridostigmine and 22 to receive placebo. The peak Vo2 increased after pyridostigmine but decreased after placebo (13.3 ± 13.4mL/min vs-40.2 ± 21.3mL/min; P< .05). The treatment effect of pyridostigmine was 53.6mL/min (95%CI, -105.2 to -2.0). Peak vsrest Vo2 (25.9 ± 15.3mL/min vs-60.8 ± 25.6mL/min; P< .01), cardiac output (-0.2 ± 0.6 L/min vs-1.9 ± 0.6 L/min; P< .05), and right atrial pressure (1.0 ± 0.5mmHg vs-0.6 ± 0.5mmHg; P< .05) were greater in the pyridostigmine group compared with placebo. Pyridostigmine improves peak Vo2 in ME/CFS by increasing cardiac output and right ventricular filling pressures. Worsening peak exercise Vo2, cardiac output, and right atrial pressure following placebo may signal the onset of postexertional malaise. We suggest that treatable neurovascular dysregulation underlies acute exercise intolerance in ME/CFS. ClinicalTrials.gov; No.: NCT03674541; URL: www. gov.

Right ventricular and cyclic guanosine monophosphate signalling abnormalities in stages B and C of heart failure with preserved ejection fraction.

AimsIdentifying early right ventricular (RV) dysfunction and impaired vasodilator reserve is challenging in heart failure with preserved ejection fraction (HFpEF). We hypothesized that cardiac magnetic resonance (CMR)‐based exercise imaging and serial cyclic guanosine monophosphate (cGMP) measurements can identify dynamic RV‐arterial uncoupling and responsiveness to pulmonary vasodilators at early stages of the HFpEF syndrome.Methods and resultsPatients with HFpEF (n = 16), impaired left ventricular relaxation due to concentric remodelling (LVCR, n = 7), and healthy controls (n = 8) underwent CMR at rest and during supine bicycle exercise with simultaneous measurements of central haemodynamics and circulating cGMP levels, before and after oral administration of 50 mg sildenafil. At rest, mean pulmonary artery pressures (mPAP) were higher in HFpEF, compared with LVCR and controls (27 ± 2, 18 ± 1, and 11 ± 1, respectively; P = 0.01), whereas biventricular volumes, heart rate, and stroke volume were similar. During exercise, LVCR and HFpEF had a greater increase in the ratio of mPAP over cardiac output than controls (5.50 ± 0.77 and 6.34 ± 0.86 vs. 2.24 ± 0.55 in controls, P = 0.005). The ratio of peak exercise to rest RV end‐systolic pressure‐volume, a surrogate of RV contractility, was significantly reduced in LVCR and HFpEF (2.32 ± 0.17 and 1.56 ± 0.08 vs. 3.49 ± 0.35 in controls, P < 0.001) and correlated with peak exercise VO2 (R 2 = 0.648, P < 0.001). cGMP levels increased with exercise across the HFpEF spectrum (P < 0.05 vs. baseline), except when postcapillary pulmonary hypertension was present at rest (P = 0.73 vs. baseline). A single sildenafil administration failed to increase circulating cGMP levels and did not improve RV performance.ConclusionExercise CMR identifies impaired RV‐arterial coupling at an early stage of HFpEF. Circulating cGMP levels phenocopy the haemodynamic spectrum in HFpEF but fail to increase after phosphodiesterase type 5 inhibition, endorsing the need for alternative interventions to increase cGMP signalling in HFpEF.

Sex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction

Right ventricular (RV) dysfunction is associated with poorer outcomes in heart failure with preserved ejection fraction (HFpEF). Although female subjects are more likely to have HFpEF, male subjects have worse prognosis and resting RV function. The contribution of dynamic RV-pulmonary arterial (RV-PA) coupling between sex and its impact on peak exercise capacity (VO2) in HFpEF is not known. The goal of this study was to investigate the differential effects of sex on RV-PA coupling during maximum incremental exercise in patients with HFpEF. This study examined rest and exercise invasive pulmonary hemodynamics in 22 male patients with HFpEF and 27 female patients with HFpEF. To further investigate the discrepancy in RV-PA response between sex, 26 age-matched control subjects (11 male subjects and 15 female subjects) were included. Single beat analysis of RV pressure waveforms was used to determine the end-systolic elastance (Ees) and pulmonary arterial elastance. RV-PA coupling was determined as the ratio of end-systolic elastance/PA elastance. Both HFpEF groups experienced decreased peak VO2 (%predicted). However, male patients with HFpEF experienced a greater decrement in peak VO2 compared with female patients (58 ± 16%vs70 ± 15%; P< .05). Male patients with HFpEF had a more pronounced increase in RV afterload, Ea (1.8 ± 0.6mmHg/mL/m2 vs1.3 ± 0.4mmHg/mL/m2; P< .05) and failed to increase RV contractility during exercise, resulting in dynamic RV-PA uncoupling (0.9 ± 0.4 vs1.2 ± 0.4; P< .05) and subsequent reduced stroke volume index augmentation. In contrast, female patients with HFpEF were able to augment RV contractility in the face of increasing afterload, preserving RV-PA coupling during exercise. Male patients with HFpEF were more compromised regarding dynamic RV-PA uncoupling and reduced peak VO2 compared with female patients. This finding was driven by both RV contractile impairment and afterload mismatch. In contrast, female patients with HFpEF had preserved RV-PA coupling during exercise and better peak exercise VO2 compared with male patients with HFpEF.

Effect of 4 -Week HICTBW Training on Cardiorespiratory Fitness in Sedentary Women

Background: It is unknown whether a shorter duration of high-intensity circuit training (HICT) could improve health-related fitness in sedentary women. Objectives: This study aims to investigate the effects of 4 weeks of HICT using body weight (HICTBW) on cardiorespiratory fitness and body composition in middle aged, sedentary women. Methods: Twenty-four women (age: 35 ± 3 years), who currently participated in exercise for less than 2 days or 150 minutes per week, were randomly assigned to either an untrained (CG; n = 12) or trained (TG; n = 12) group. The TG group performed a HICTBW program for four weeks (3 times weekly), whereas the CG group performed their usual activity. All participants were asked to maintain their current eating habits. Parameters were compared before and after 4 weeks. Results: Exercise VO2peak, relative VO2peak, heart rate and workload significantly increased over the 4-week period in the TG compared with CG at the end of the 4 weeks of training (P 0.05). Conclusions: Our findings suggest that a 4-week HICTBW program (12 poses per circuit, 8 minutes each circuit three times weekly for 4 weeks) was sufficient to improve cardiorespiratory fitness but had no effect on body composition or weight loss in sedentary women who did not change their dietary habits.

Physiological and Perceptual Responses to Step-Wise and Ramp Graded Exercise Tests in Children

Step-wise graded exercise tests are common protocols to measure aerobic fitness in children but have limitations due to the nature of the increments. Modifying these tests to a ramp protocol could overcome some of these limitations. PURPOSE: To examine physiological and perceptual responses to step-wise and ramped graded exercise tests in children (n = 8; age = 13.3 ± 2.2 yrs.). METHODS: The standardized James protocol (STEP) and a modified-ramp James protocol (RAMP) were performed on a cycle ergometer on separate days. Protocol order was counterbalanced. STEP commenced with three 3-min stages, followed by 1-min stages. Work rate increases were based on body surface area. For RAMP, work rate was ramped to match the 3-min and 1-min stages of STEP. Work rate was increased until volitional exhaustion for both tests. Oxygen consumption (VO2), heart rate (HR), respiratory exchange ratio (RER) and OMNI ratings of perceived exertion for chest (RPE-chest), legs (RPE-legs) and overall (RPE-overall) were recorded at the end of each 3-minute stage and peak exercise. Physiological and perceptual responses between tests were compared using two-way repeated-measure ANOVAs and test time (TT) and peak power (PP) were compared using repeated measure t-tests. Significance was established at p<0.05. RESULTS: The physiological and RPE responses were similar between tests at the end of each 3-min submaximal stage (p>0.05). At peak exercise, absolute and relative VO2 for STEP were 2.17 ± 0.67 L∙min-1 and 42.5± 5.9 ml∙kg-1 ∙min-1. For RAMP, absolute and relative VO2peak were 2.33± 0.89 L∙min-1 and 45.3 ± 8.9 ml∙kg-1 ∙min-1. The differences were not significant. There were no differences between STEP and RAMP for peak HR (196.3 ± 9.8 bpm vs. 196.1 ± 9.7 bpm) and peak RER (1.24 ± 0.11 vs. 1.21 ± 0.06). At peak exercise, RPE-chest, RPE-leg and RPE-overall were similar between STEP (4.8 ± 4.0, 8.4 ± 2.1 and 7.6 ± 3.0, respectively) and RAMP (5.6 ± 3.4, 8.5± 2.3 and 8.0± 1.8, respectively) (p>0.05). TT and PP for STEP were 11.3± 2.5 min and 196.8 ± 70.7 W and 12.4 ± 2.4 min and 210.3 ± 65.5 W for RAMP (p=0.11 and p=0.12, respectively) CONCLUSION: Although limitations in step-wise protocols exist, submaximal and peak physiological and perceptual responses were similar to a ramp protocol. Both protocols may be appropriate in children to measure aerobic fitness.

Peak Exercise and Post‐Exercise Recovery Oxygen Uptake and Muscle Oxygenation in Patients with Heart Failure and Preserved Ejection Fraction and Healthy Matched Adults

BackgroundExercise intolerance and muscle dysfunction characterize heart failure with preserved ejection fraction (HFpEF). Exercise intolerance, as measured by low peak oxygen uptake (VO2), and slow post‐exercise VO2 recovery are predictors of mortality. The relationship between peak exercise and recovery VO2 and muscle oxygenation is unknown in this population.PurposeWe tested the hypothesis that post‐exercise VO2 recovery would be slower in patients with HFpEF compared to controls, and that slower post‐exercise VO2 recovery would be related to slower muscle oxygenation recovery in patients with HFpEF.MethodsEight patients with HFpEF and 8 healthy age‐and sex‐matched controls completed a stationary cycling peak exercise test to volition fatigue followed by 5‐min of passive recovery. Pulmonary VO2 (gas exchange via metabolic cart) and muscle oxygenation (tissue muscle oxygenation index, TOI) and deoxygenated hemoglobin (HHb via near infrared spectroscopy) were sampled continuously during the exercise test and recovery. Breath‐by‐breath VO2 data were linearly interpolated to 1‐s intervals, and both VO2 and NIRS data were averaged into 5‐s time bins. VO2 recovery data were mono‐exponentially curve‐fitted (OriginPro, 2017) to yield a recovery time constant (tau) and amplitude change. TOI and HHb at end‐exercise, end‐recovery, and the amplitude change were calculated as 10‐s averages. Statistical analyses included independent t‐tests and stepwise multiple regression. Significance was accepted at P&lt;0.05.ResultsPeak VO2 (15.8 ± 5.9 vs. 24.6 ± 6.6 mL/kg/min, P = 0.011) and VO2 recovery amplitude (−10.0 ± 4.9 vs. −15.1 ± 4.2 mL/kg/min, P = 0.041) were significantly lower in patients with HFpEF compared to matched controls. However, there were no differences between groups in VO2 recovery tau (98 ± 43 vs. 71 ± 16 s, P = 0.122) nor in any TOI or HHb parameter (all P&gt;0.05). Stepwise regression by group to predict peak VO2 yielded a positive regression using both peak‐exercise HHb and VO2 recovery amplitude in HFpEF (R2 = 0.957, P&lt;0.001) but only VO2 recovery amplitude in controls (R2 = 0.947, P&lt;0.001). The same parameters predicted VO2 recovery tau in HFpEF (R2 = 0.940, P = 0.001) with no significant finding in controls (P&gt;0.05).ConclusionsSlower post‐exercise VO2 recovery in patients with HFpEF compared to their healthy counterparts was not confirmed with these data, although this may be largely influenced by the elevated variance in the HFpEF group, or the mild‐moderate HFpEF severity. Regression analyses suggest that the level of muscle deoxygenation, i.e., the level of O2 extraction, during peak exercise may be a more important contributor to peak VO2 in patients with HFpEF compared to their healthy counterparts. The latter may suggest a muscle‐based limitation in HFpEF not observed in healthy controls.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Mechanisms of Exercise Intolerance in Heart Failure with Reduced Ejection Fraction: Influence of COPD

IntroductionExercise intolerance is a hallmark of heart failure with reduced ejection fraction (HFrEF) resulting from a variety of factors including comprised oxygen delivery. A common comorbidity of HFrEF is chronic obstructive pulmonary disease (COPD), which is independently associated with reduced exercise tolerance and cardiac output (Q) as well as peripheral dysfunction similar to HFrEF. It is currently unknown if HFrEF and coexisting COPD (HFrEF+COPD) exhibit worsened exercise tolerance and whether the mechanisms thereof are similar to HFrEF alone. We hypothesized that patients with HFrEF+COPD demonstrate further reductions in peak VO2 and workload subsequent to a lower peak Q and arterio‐mixed venous O2 content difference (C(a‐v)O2) compared to HFrEF alone.MethodsHFrEF+COPD (n=16) and HFrEF (n=17) (age: 57±7 vs 54±6 yrs; EF%: 20±5 vs 21±5; height: 173±7 vs 174±7 cm; weight: 88±14 vs 86±17 kg; all p&gt;0.18) underwent peak exercise testing during right heart catheterization. At rest and peak exercise, invasive hemodynamic, cardiac pressures, and arterial pressures were performed. Heart rate and oxygen uptake (VO2) were measured at rest and peak exercise via 12‐lead ECG and metabolic measurement system, respectively. Convective oxygen delivery was calculated as Q multiplied by CaO2.ResultsPeak exercise VO2 and workload were lower in HFrEF+COPD compared to HFrEF (7.0±1.9 vs. 9.9±2.7 mL/min/kg; 34±7 vs. 45±12 watts; both p&lt;0.01). At peak exercise, Q and stroke volume were lower in HFrEF+COPD than HFrEF (4.8±1.3 vs. 7.0±3.0 L/min; 52±16 vs. 75±28 mL; both p&lt;0.01). Significant relationships existed between delta VO2 and Q (peak exercise minus resting) in HFrEF+COPD and HFrEF (r=0.84 and r=0.89; both p&lt;0.01); however, HFrEF+COPD had a significantly lower slope (p=0.02). Peak exercise C(a‐v)O2 was not different between HFrEF+COPD and HFrEF (12.9±2.3 vs. 12.8±2.6 mL/dL; p=0.89). No differences were present in heart rate or hemoglobin at peak exercise (p&gt;0.73). Delta VO2 and C(a‐v)O2 was significantly related for HFrEF+COPD (r=0.68; p&lt;0.01), but not HFrEF (r=0.14, p=0.57). At peak exercise, HFrEF+COPD had lower convective oxygen delivery (845±239 vs. 1230±517 mL/min; p&lt;0.01).ConclusionsPatients with HFrEF and concurrent COPD demonstrate worsened exercise tolerance compared to HFrEF resulting from reduced oxygen delivery. These data suggest HFrEF with COPD exhibit more severe central and peripheral abnormalities than HFrEF alone.Support or Funding InformationNHLBI RO1 HL126638This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of ventricular function and volumes on exercise capacity in adults with repaired Tetralogy of Fallot

ObjectivesInvestigate the effects of left and right ventricular function and severity of pulmonary valve regurgitation, quantified by cardiac magnetic resonance (CMR), on exercise tolerance in adult patients who underwent ToF repair at a young age. MethodsThis is a retrospective cohort study of 52 patients after ToF surgery and 33 age- and sex-matched healthy volunteers. CMR and cardiopulmonary exercise testing (CPET) were performed on all patients; CPET was performed on control subjects. ResultsThe main finding of CPET was a severe decrease in oxygen uptake at peak exercise VO2peak in TOF patients. The patients were characterized also by lower pulse O2peak and heart rate at peak exercise. Ejection fraction of the right and left ventricles was correlated (r=0,32; p=0,03). Left ventricle ejection fraction was negatively correlated with right ventricular volumes (r=−0,34; p=0,01) and right ventricular mass (r=−046; p<0,00). Right ventricular mass was positively correlated with left ventricular variables (left ventricle end diastolic volume, r=0,43; p=0,002; left ventricle end systolic volume, r=0,54; p<0,00) as was VO2peak: LVEDV (r=0,38; p=0,01); LVESV (r=0,33; p=0,03) and LV mass (r=0,42; p=0,006). ConclusionExercise intolerance in adults with repaired ToF is markedly depressed. The decreased exercise capacity is correlated with impaired RV function and may be associated also with LV dysfunction, which suggests right-to-left ventricular interaction.

Comparison of the long-term reproducibility of the walk test and of exercise peak oxygen consumption in patients with preserved exercise capacity

Short-term and long-term reproducibility of the cardiopulmonary (CPX) exercise test have been established. Though short and mid-term reproducibility of the walk test has been ascertained, this was not extensively done for the long-term reproducibility. The aim of the study was to examine the long-term reproducibility of distance walked in an allotted time and to check the stability of the relationship between walked distance and exercise peak VO2 (pVO2).Methods: Forty six subjects (33 men; 57 ± 14 years), referred for functional capacity assessment, were studied twice by CPX and walking test. On the same day, CPX was performed on a bicycle or a treadmill and walk test in a corridor as required by specific guidelines. We performed a 12-minute walk test and the distance covered in six minutes was systematically taken down. A free time interval of 1.5 hours was observed between the exercise tests. Distance walked in the allotted time and pVO2 were analysed. Reproducibility was assessed according to Bland and Altman plots and intra-class coefficient correlation (ICC). The relationship between distance ambulated and pVO2 was analysed by the Spearman coefficient correlation.Results: The time interval between the two evaluations was 290 ± 10 days. During this meantime, for those subjects having drug treatment, no change was recorded in their regimen. BMI remained stable for the entire studied population (28 ± 5 kg/m2). Minute walked distance was respectively 522 ± 83 and 527 ± 76 m in six minutes, 1033 ± 182 and 1041 ± 153 m in 12 minutes. pVO2 was 21 ± 7 and 22 ± 7 ml/kg/min (all p = NS). The walk test was reproducible in the long-term, regardless of the modality (6 or 12-minute walk) as shown by the Bland–Altman plots and the high ICC of .89. Spearman’s rho coefficient between distance ambulated and pVO2 was modest and remained stable over time whatever the allotted time: Spearman’s r = .54; p = .0011 (1st evaluation) and Spearman’s r = .51; p = .0019 (2nd evaluation) between 6-minute distance walked and pVO2.Conclusions: The walking distance in an allotted time seems highly reproducible in the long-term. Its relationship with pVO2 remains stable over time. It could be of value for repeated assessment of patients’ exercise capacity in a first step. Further evaluation in a larger population is needed to confirm our result and its usefulness in clinical practice.

Patient education significantly improves quality of life, exercise capacity and BNP level in stable heart failure patients.

The aim of the study was to evaluate the impact of complex ambulatory education on quality of life, exercise capacity and B-type natriuretic peptide (BNP) level in chronic stable heart failure patients. Heart failure patients in NYHA class II/III (n = 31) on optimal medical treatment were recruited from the outpatient department. The following data were evaluated before and 2 months after the patient education: quality of life (evaluated by the Minnesota questionnaire), peak exercise oxygen consumption (VO2) and BNP level. The mean general quality of life evaluation index (QoLES) decreased significantly in 2 months after the education (37.90 +/- 18.78 versus 49.39 +/- 17.86 prior to the education, P < 0.001), an improvement in quality of life. Peak exercise VO2 in 2 months after the tuition significantly increased (19.26 +/- 7.22 versus baseline 16.25 +/- 3.69 ml/kg/min; P = 0.013) as well as the anaerobic threshold (AT VO2 was 12.694 +/- 3.28 ml/kg/min versus baseline 11.197 +/- 2.47 ml/kg/min; P = 0.003). The indices reflecting external load also increased significantly: workload, duration of the exercise and METs. A significant proportion of the patients 2 months after the education moved to lower NYHA functional classes. Plasma BNP level decreased significantly in 2 months after the tuition: 224 +/- 340.36 versus baseline 348.41 +/- 471.99 ng/I; P = 0.023. Patient education with the emphasis on adherence, self-care management and physical training has a reliable positive impact on the quality of life, exercise capacity and plasma levels of B-type natriuretic peptide in the population of stable moderate HF patients.

Lvad pump speed increase is associated with increased peak exercise cardiac output and vo2, postponed anaerobic threshold and improved ventilatory efficiency

BackgroundsPeak exercise cardiac output (CO) increase is associated with an increase of peak oxygen uptake (VO2), provided that arteriovenous O2 difference [Δ(Ca−Cv)O2] does not decrease. At anaerobic threshold, VO2, is related to CO.We tested the hypothesis that, in heart failure (HF) patients with left ventricular assistance device (LVAD), an acute increase of CO obtained through changes in LVAD pump speed is associated with peak exercise and anaerobic threshold VO2 increase. MethodsFifteen of 20 patients bearing LVAD (Jarvik 2000) enrolled in the study successfully performed peak exercise evaluation. All patients had severe HF as shown by clinical evaluation, laboratory tests, echocardiography, spirometry with alveolar-capillary diffusion, and maximal cardiopulmonary exercise testing (CPET). CPETs with non-invasive CO measurements at rest and peak exercise were done on 2days at LVAD pump speed set randomly at 2 and 4. ResultsIncreasing LVAD pump speed from 2 to 4 increased CO from 3.4±0.9 to 3.8±1.0L/min (ΔCO 0.4±0.6L/min, p=0.04) and from 5.3±1.3 to 5.9±1.4L/min (ΔCO 0.6±0.7L/min, p<0.01) at rest and peak exercise, respectively. Similarly, VO2 increased from 788±169 to 841±152mL/min (ΔVO2 52±76mL/min, p=0.01) and from 568±116 to 619±124mL/min (ΔVO2 69±96mL/min, p=0.02) at peak exercise and at anaerobic threshold, respectively. Δ(Ca−Cv)O2 did not change significantly, while ventilatory efficiency improved (VE/VCO2 slope from 39.9±5.4 to 34.9±8.3, ΔVE/VCO2 −5.0±6.4, p<0.01). ConclusionsIn HF, an increase in CO with a higher LVAD pump speed is associated with increased peak VO2, postponed anaerobic threshold, and improved ventilatory efficiency.

Predictive value of exhaled nitric oxide and aerobic capacity for sepsis complications after liver transplantation.

Our objective was to investigate the predictive value of fractional nitric oxide (NO) concentration in exhaled breath (FeNO) and aerobic capacity (peak VO2 ) for postoperative sepsis in liver transplantation candidates. Patients were identified and charts of all consecutive patients were prospectively reviewed. Bacterial sepsis represented the commonest postoperative complications (30%), which was attributed to peritonitis, pneumonia, and catheter-related infections. Preoperative FeNO and peak VO2 values were lower in patients with postoperative sepsis. Patients with sepsis required higher needs for mechanical ventilation and ICU length of stay. Inverse correlation was found between logarithmically FeNO-transformed data and systolic pulmonary artery pressure (r = -0.348; P = 0.018). Multivariate analyses using bootstrap sampling method indicated that odds of sepsis were associated with lower values of peak exercise VO2 [OR = 0.790 (0.592; 0.925)] and reduced log(FeNo) [OR = 0.027 (0.001; 0.451)], but not with higher MELD scores [OR = 1.141 (0.970; 1.486)]. By evaluating the cutoff for the ROC curves in each bootstrap resampling, median and 95% confidence interval were calculated for peak VO2 : 17 [16.2; 22] ml/kg/min and FeNO: 17.2 [13.0; 33.9] ppb. We conclude that low peak exercise VO2 and reduced FeNO may help identify patients who are at risk to develop perioperative sepsis.

THE EFFECTS OF HIGH INTENSITY INTERVAL TRAINING ON CLINICAL SYMPTOMS AND FUNCTIONAL CAPACITY IN ADULTS WITH NEUROMUSCULAR DISEASE

BackgroundNeuromuscular disease includes a spectrum of inflammatory and mitochondrial myopathies where dysfunction in the energy–producing mitochondria can cause muscle weakness, exercise intolerance and fatigue. Continuous endurance training has been shown...

Moderate acute exercise (70% VO2 peak) induces TGF‐β, α‐amylase and IgA in saliva during recovery

Strenuous exercise promotes changes in salivary IgA and can be associated with a high incidence of upper respiratory tract Infections. However, moderate exercise enhances immune function. The effect of exercise on salivary IgA has been well studied, but its effect on other immunological parameters is poorly studied. Thus, this study determined the effect of moderate acute exercise on immunological salivary parameters, such as the levels of cytokines (TGF-β and IL-5), IgA, α-amylase and total protein, over 24h. Ten male adult subjects exercised for 60min at an intensity of 70% VO2 peak. Saliva samples were collected before ('basal') and 0, 12 and 24h after an exercise session. The total salivary protein was lower after 12 and 24h than immediately after exercise, whereas α-amylase increased at 12 and 24h after exercise compared with basal levels. The IgA concentration was increased at 24h after exercise relative to immediately after exercise, and there was no difference in the IL-5 while TGF-β concentration increased in recovery. In conclusion, 70% VO2 peak exercise does not induce changes immediately after exercise, but after 24h, it produces an increase in salivary TGF-β without changing IL-5.

124: Echocardiographic determinants of maximal exercise capacity in asymptomatic patients with primary mitral regurgitation

Despite a symptom-based management recommended by current guidelines in patients with primary mitral regurgitation (MR), the assessment of maximal exercise capacity (MEC) is rarely performed. MEC is relatively unexplored in these patients and its exercise determinants remain unknown. We prospectively studied 63 asymptomatic patients (60±13 years, 52% of male) with at least moderate MR and with preserved left ventricular (LV) systolic function in whom comprehensive resting and exercise echocardiography and cardiopulmonary exercise test were performed. MEC was assessed using peak exercise VO2 and widely varied over patients (mean: 23.6±7, median: 22.7, range: 10.2–42.4 ml/kg/min). According to the median of peak VO2, patients with reduced MEC were significantly older (p=0.0052) and were more frequently women (p=0.02). There was no other significant difference between the 2 groups (reduced vs. preserved MEC) regarding demographic and clinical data and medication. During exercise, Peak VO2 was significantly correlated with exercise LV stroke volume (r=−0.33, p=0.02) and there was a trend for significant correlation with exercise RegV and effective regurgitant orifice area (r=−0.32, p=0.05 and r=−0.3, p=0.07, respectively). In addition, the best correlations with peak VO2 were found with exercise SPAP (r=−0.52, p<0.0001) and exercise LA volume (r=−0.59, p<0.0001). In multiple regression analysis (model r 2 =0.67), after adjustment for exercise LV stroke volume and resting E/Ea, age (β=−0.17± 0.07, p=0.02), sex (β=−3.1±0.8, p=0.0006), exercise LA volume (β=−0.12± 0.03, p=0.02) and exercise SPAP (β=−0.15±0.06, p=0.0003) were identified as independent predictors of peak exercise VO2. In asymptomatic patients with primary MR and preserved LV systolic function, MEC may vary considerably. The main independent determinants of MEC are related to MR consequences on LA and SPAP, in particular during exercise.

Time Course for Recovery of Peak Aerobic Power After Blood Donation

Peak aerobic power (VO2peak) is decreased after blood donation, but the time course for full recovery is unknown. We measured VO2peak and exercise time to fatigue before and weekly for 4 weeks after 450-ml blood donation at a blood donor clinic, to determine the time course of recovery. Twelve moderately active individuals (2 women, 10 men; 24.3 ± 5.2 years) of average aerobic fitness (based on their VO2peak relative to normative values) completed VO2peak exercise tests before donation, the day after donation, and at weekly intervals for 4 weeks after donation. VO2peak was determined by an incremental exercise test on a cycle ergometer. At baseline, mean absolute and relative VO2peak values were 4.06 ± 0.92 L·min(-1) and 46.6 ± 7.0 ml·kg(-1)·min(-1), respectively. VO2peak was significantly decreased on day 1 (3.85 ± 0.89 L·min(-1); 44.0 ± 6.5 ml·kg(-1)·min(-1)) and during week 2 (3.91 ± 0.97 L·min(-1); 44.5 ± 7.2 ml·kg(-1)·min(-1)) after blood donation (p < 0.05), and recovered at week 3 after donation. Time to fatigue and peak heart rate were not significantly affected by blood donation. We conclude that blood donation causes a significant decrease in VO2peak for between 2 and 3 weeks. The practical application of this study is that aerobic power in people of average fitness will be decreased, up to 3 weeks after donating blood. Despite this, there is no effect of blood donation on performance as measured by time to fatigue during an incremental test on a cycle ergometer.

Patient education significantly improves quality of life, exercise capacity and BNP level in stable heart failure patients

Summary — The aim of the study was to evaluate the impact of complex ambulatory education on quality of life, exercise capacity and B-type natriuretic peptide (BNP) level in chronic stable heart failure patients.Material and methods — Heart failure patients in NYHA class II/III (n = 31) on optimal medical treatment were recruited from the outpatient department.The following data were evaluated before and 2 months after the patient education: quality of life (evaluated by the Minnesota questionnaire), peak exercise oxygen consumption (VO2) and BNP level.Results — The mean general quality of life evaluation index (QoLES) decreased significantly in 2 months after the education (37.90 ± 18.78 versus 49.39 ± 17.86 prior to the education, P < 0.001), an improvement in quality of life. Peak exercise VO2 in 2 months after the tuition significantly increased (19.26 ± 7.22 versus baseline 16.25 ± 3.69 ml/kg/min; P = 0.013) as well as the anaerobic threshold (AT VO2 was 12.694 ± 3.28 ml/kg/min versus baseline 11.197 ± 2.47 ml/kg/min; P = 0.003).The indices reflecting external load also increased significantly: workload, duration of the exercise and METs. A significant proportion of the patients 2 months after the education moved to lower NYHA functional classes. Plasma BNP level decreased significantly in 2 months after the tuition: 224 ± 340.36 versus baseline 348.41 ± 471.99 ng/l; P = 0.023.Conclusions— Patient education with the emphasis on adherence, self-care management and physical training has a reliable positive impact on the quality of life, exercise capacity and plasma levels of B-type natriuretic peptide in the population of stable moderate HF patients.

Peak exercise responses in heart failure: back to basics

Evaluating central haemodynamics became a prominent cardiological feature in the 1950s following Sarnoff and Berglund's introduction of Starling's Law into practice via a family of ventricular function curves,1 but it went out of favour after 1981 when Benge2 and Franciosa3 claimed discrepancy between haemodynamics and exercise capacity in heart failure (HF) patients. Dismissing its value became fashionable in subsequent decades with further emphasis of its dissociation with changes in symptoms. In 1991, Mancini and colleagues4 greatly contributed to the widespread use of cardiopulmonary exercise testing (CPX) by showing its prognostic value in patients with severe HF referred for transplantation. Since this landmark study, a large number of studies have confirmed the unsurpassed prognostic value of peak exercise capacity, generally reported as peak oxygen consumption (peak VO2/kg), in HF patients. The simple explanation for this is that, according to the Fick principle, peak exercise VO2 is determined by peak exercise cardiac output and arteriovenous oxygen difference. When Chomsky et al. 5 tried to reintroduce the usefulness of haemodynamic evaluation in selecting transplant candidates in 1996, they were rather overwhelmed by counter arguments.6,7 The emergence of such discrepancies is clearly puzzling, especially in view of the fact that central haemodynamics offer by far the best means of looking into cardiac performance and dysfunction. There are a number of reasons why haemodynamic evaluations went out of favour. Chief amongst these are the choice of unrepresentative haemodynamic variables and the misplaced belief that measurements at rest can be representative of actual cardiac function irrespective of reserve capacity. Such a misconception probably stemmed from the misleadingly title of the 1981 paper by Franciosa,3 which also failed to highlight that in their own study, exercise haemodynamics actually correlated very well with exercise capacity. A more … *Corresponding author. Tel: +33 1 4995 6608, Fax: +33 1 4995 8439, Hopital Lariboisiere, Assistance Publique, 2 rue Ambroise Pare, 75010 Paris, France. Email: alain.cohen-solal{at}lrb.aphp.fr.

Effect of Aldosterone Antagonism on Exercise Tolerance, Doppler Diastolic Function, and Quality of Life in Older Women With Diastolic Heart Failure

Optimal therapy for diastolic heart failure (DHF), the most common form of heart failure in older persons, is unclear. To determine the effect of aldosterone antagonism in DHF, the authors conducted an open-label preliminary trial of spironolactone 25 mg/d in 11 women with DHF. Cardiopulmonary exercise testing, Doppler echocardiography, and a quality-of-life survey were administered at baseline and after 4 months. Peak exercise VO(2) increased by 8.3% (P=.001), the ratio of Doppler diastolic early filling velocity to mitral annulus velocity decreased by 25% (P=.02), quality-of-life score improved by 21% (P=.16 for trend), and median New York Heart Association class improved from class III to class II (P=.004). Findings from this preliminary study confirm the role of aldosterone in the pathophysiology of DHF and suggest that aldosterone antagonism may benefit such patients. These hypotheses are currently being tested in two separated National Institutes of Health-funded, randomized trials, the Spironolactone for Failure in the Elderly (SPIFFIE) and the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trials.