Symptom-limited Exercise Test Research Articles

Cardiorespiratory Fitness is a Strong, Independent Predictor of Radiation Induced Fatigue in Breast Cancer

Fatigue is among the most common but most poorly understood toxicities of patients undergoing radiation treatment for primary breast cancer, predisposing to poor quality of life, treatment non-compliance and comorbidity. In this prospective study, we sought to investigate whether an integrative measure of cardiopulmonary function under exercise conditions (cardiorespiratory fitness as evaluated by peak oxygen consumption, VO2peak) predicted fatigue in patients with early stage breast cancer undergoing radiation treatment. Patients with stage Tis-T2N0M0 breast cancer undergoing radiation to the breast performed a symptom-limited cardiopulmonary exercise test (CPET) on an electronic motorized treadmill test with 12-lead ECG monitoring (Mac® 5000, GE Healthcare) to assess cardiorespiratory fitness (VO2peak; ml O2.kg-1.min-1) according to standard procedures. Fatigue was assessed by the FACIT fatigue scale survey. Both assessments were performed during or after radiation therapy (typically within 30 days). To isolate the effects of radiation on fatigue and VO2peak, patients who received cytotoxic chemotherapy were excluded. All patients were treated with an opposed tangent technique to a dose of 4240 cGy in 16 fractions +/- a lumpectomy bed boost of 1000 cGy in 4 fractions. Twenty-eight patients (median age: 51.5, range 31-71) successfully performed both CPET and the FACIT surveys. The mean VO2 peak was 26.7 ml O2.kg-1.min-1(range 16.7- 41.7). The mean fatigue score was 38.6 (range 10-52, lower values indicating more fatigue). In age-adjusted analysis, lower VO2peak was a significant predictor of fatigue (r (25) = 0.49, n = 28, p = 0.009). Radiation-induced fatigue appears to be driven by a decrease in global cardiopulmonary function. Larger prospective studies are needed to further investigate this novel finding.

Cardiopulmonary Exercise Metrics Demonstrate that CF-LVAD Patients Suffer from Residual Heart Failure

Background Continuous flow left ventricular assist devices (CF-LVADs) improve survival and quality-of-life for patients with heart failure with reduced ejection fraction (HFrEF), but exercise capacity remains reduced. While resting and exertional cardiovascular performance is described in the setting of CF-LVAD support, data on pulmonary performance are limited. The primary objective of this study was to describe changes in metrics of cardiopulmonary performance during exercise among HFrEF patients before and after CF-LVAD implantation. Methods 11 HFrEF patients completed submaximal and symptom-limited cardiopulmonary exercise testing (CPET) on three separate visits. Visit 1 involved CPET testing ∼2-4 weeks prior to CF-LVAD implantation. Visit 2 involved CPET testing ∼3 months post-LVAD at a constant pump speed. Visit 3 involved CPET testing ∼4-5 months post-LVAD with progressive increases in LVAD pump speed during exercise. Exercise involved two levels of submaximal exercise below the ventilatory threshold (steady-states 1-2) and peak exercise on an upright cycle ergometer. Breath-by-breath gas exchange parameters (oxygen uptake [VO2], carbon dioxide production [VCO2], minute ventilation [VE]) were recorded by indirect calorimetry. Results Clinical characteristics are summarized in table 1. There was no improvement in submaximal or peak VO2 following LVAD implantation (figure 1) regardless of whether individuals exercised at constant speed (visit 2) or exercised with progressive pump speed increases (visit 3). Ventilatory efficiency improved modestly on visits 2 and 3, but remained severely impaired. Oxygen uptake efficiency slope (OUES) was largely unchanged post-LVAD. Changes in end-tidal carbon dioxide during exercise were similar on all three visits. Conclusions HFrEF patients suffer from severe impairments in functional capacity as measured by oxygen uptake following CF-LVAD implantation, which does not improve with modulations in pump speed. CF-LVAD patients also suffer from severe impairments in ventilatory efficiency. These data suggest that CF-LVAD patients suffer from residual heart failure that is precipitated by submaximal exercise and not alleviated by modulations in pump speed.

Professional Doctorate in Clinical Exercise Physiology

Professional Doctorate in Clinical Exercise Physiology

COVID-19 — Is It Time for Exercise Clinicians to Prehabilitate “High Risk” Respiratory Patients?

COVID-19 — Is It Time for Exercise Clinicians to Prehabilitate “High Risk” Respiratory Patients?

The Predictive Value Of The Sf-36 Questionnaire In Determining CPET Performance In Patients With ME/CFS

INTRODUCTION: Patients diagnosed with Myalgic Encephalomyelitis (ME/CFS) tend to have difficulties with higher-intensity exercise, and usually show diminished maximal exercise capabilities when compared to their sedentary healthy counterparts (sHC). Thus, it is important to find new ways to identify patients most at risk for diminished exercise performance as soon as possible. PURPOSE: The present study seeks to determine the predictive validity of the Short Form Health Questionnaire (SF-36) and its subscales as a non-exercise component in patient evaluation. METHODS: 18 male patients diagnosed with ME/CFS (Age: 39.2 ± 12.8 years) and 18 male sedentary healthy controls (Age: 39.9 ± 13.4 years) were asked to fill out the SF-36 health survey before participating in a symptom-limited maximal exercise test (CPET). CPET was performed on a cycle ergometer, and initial resistance was set at 30 Watts with a 30 Watt increase every 2 minutes. Subjects were asked to maintain a cycling cadence of 60-70 RPM for as long as possible, or until they experienced any of the predetermined symptoms. Maximal exercise data and veniality efficiency measures were recorded and used in correlative analyses. RESULTS: Significant differences were observed between ME/CFS and sHC in all relevant subscales of the SF-36 (p < 0.005 in all cases). The Physical Functioning, Vitality and Physical Health subscales were all positively correlated with maximal oxygen uptake (VO2 Max) in the ME/CFS group (r = 0.67, p <0.005; r = 0.59, p <0.05; and r = 0.65, p < 0.005 respectively), but showed poor correlations in the sHC group (r = 0.28, p = 0.24; r = 0.16, p = 0.51; r = 0.11, p = 0.65 respectively). Although there were significant differences in VE/VCO2 slopes between the groups (p < 0.05), neither group showed strong correlations between and subscales and ventilatory efficiency. CONCLUSIONS: The SF-36 and its subscales showed strong correlations with maximal exercise performance in subjects diagnosed with ME/CFS. These results were not observed in sHC, possibly due in part to the large percentage of “perfect” scores recorded in this group. While the SF-36 did not show any significant correlations with inter-test ventilatory efficiency measures, it might still hold some value in predicting outcomes of maximal CPETs in subjects with diminished exercise capacity.

Dynamic right ventricular function response to incremental exercise in pulmonary hypertension.

Pulmonary hypertension is a progressive disease whose survival is linked to adequate right ventricle adaptation to its afterload. In the current study, we performed an in-depth characterization of right ventricle function during maximum incremental exercise in patients with pulmonary hypertension and how it relates to exercise capacity. A total of 377 pulmonary hypertension patients who completed a maximum symptom-limited invasive cardiopulmonary exercise testing were evaluated to identify 45 patients with heart failure with preserved ejection fraction, 48 with exercise pulmonary hypertension, and 47 with established pulmonary arterial hypertension. These patients were compared to 17 age- and gender-matched normal controls. Load-adjusted right ventricle function was quantified as the ratio of right ventricle stroke work index to pulmonary arterial elastance. All patients with pulmonary hypertension had reduced peak VO2 %predicted compared to controls. Right ventricle function deteriorated for all pulmonary hypertension groups by 50% of peak VO2. Worsening of right ventricle function during freewheeling exercise was associated with greater reduction in peak VO2 compared to those whose right ventricle function deteriorated at later exercise stages (i.e. min 1, 2, and 3). On multivariate analysis, reduced ratio of right ventricle stroke work index to arterial elastance was an independent predictor of peak VO2 %predicted (β-Coefficient –5.46, 95% CI: –9.47 to –1.47, p = 0.01). Right ventricle function deteriorates early during incremental exercise in pulmonary hypertension, occurring by 50% of peak oxygen uptake. The current study demonstrates that right ventricle dysfunction is an early phenomenon during incremental exercise in pulmonary hypertension, occurring by 50% of peak oxygen uptake. The threshold at which right ventricle function is compromised during incremental exercise in pulmonary hypertension influences aerobic capacity and may help guide exercise strategies to mitigate dynamic worsening of right ventricle function during exercise training.

Serial Assessment Of The Cardiorespiratory Fitness Vital Sign: Prognostic Significance One Year Post Cardiac Rehabilitation

Cardiorespiratory fitness (CRF) consistently demonstrates robust prognostic value in apparently healthy individuals and in those at risk for or diagnosed with one or more chronic conditions. While CRF at baseline and immediately following cardiac rehabilitation (CR) hold prognostic value, little is known about the significance of serial CRF assessments over a prolonged period. PURPOSE: Assess the prognostic utility of serial CRF assessments in patients completing CR. METHODS: 3,185 patients (mean age = 62 ±10 years, 82% male) with cardiovascular disease (CVD) that were referred to and completed a 12-week exercise-based CR program were included. All patients completed a symptom-limited treadmill exercise test at baseline, immediately following CR and at 1-year follow-up. Peak metabolic equivalents (METs) were determined at each exercise test from treadmill speed and grade. The difference between peak METs at baseline and immediately post CR and between baseline and 1-year post CR were also calculated. Patients were subsequently tracked for all-cause mortality. RESULTS: 206 subjects died during the tracking period (mean tracking = 79 ±34 months). Peak METs at baseline (Mean = 7.7 ±2.0 METs, HR: 0.66, 95% CI: 0.62-0.71, p<0.001), immediately following CR (Mean = 8.7 ±2.0 METs, HR: 0.65, 95% CI: 0.60-0.69, p<0.001) and 1-year post CR (Mean = 8.6 ±2.2 METs HR: 0.65, 95% CI: 0.61-0.69, p<0.001) were all significant predictors of survival. The mean change in peak METs from baseline to immediate post CR (0.88 ±1.4 METs) and from baseline to 1-year post CR (0.88 ±1.3 METs) was significant (p<0.001). However, only the change in peak METs from baseline to 1-year post CR was a significant predictor of survival (HR: 0.73, 95% CI: 0.66-0.80, p<0.001). CONCLUSIONS: The current findings again demonstrate the prognostic significance of the CRF vital sign in patients with CVD undergoing CR. Our results indicate continued serial assessment of the CRF, in this analysis 1-year following completion of CR, provides important prognostic information. In particular, maintenance of CRF improvement following CR over the long-term is clinically important and should be monitored.

Relationship of Left Atrial Volume Index with Exercise Functional Capacity among Post-Percutaneous Coronary Intervention Patients

INTRODUCTION: Recent evidence highlighted the importance of increased left atrial volume index (LAVI) as a powerful predictor of mortality after acute myocardial infarction (AMI). This study aimed to investigate whether LAVI correlates with the level of functional capacity assessed by treadmill exercise test using metabolic equivalents (METS). METHODS: Twenty-four patients with AMI who underwent percutaneous coronary intervention (PCI) were included in this study. Two-dimensional echocardiography done after PCI were reviewed and the following parameters were obtained: left atrial size, LAVI and left ventricular ejection fraction (LVEF). At least two weeks post-PCI, patients underwent symptom-limited treadmill exercise test using the National Institute for Health (NIH)/NEPTET protocol. Pearson product moment correlation was used to determine the linear correlation between LAVI and exercise capacity measured by METS score. RESULTS: Majority of the patients were male with a mean age of 49.5 years. Majority were hypertensive, overweight and were current smokers. The mean ejection fraction (56.0 + 1.0) was preserved while the mean LAVI (21.3 + 5.8) was within normal ranges. The median METS achieved patients was 7.5. Pearson product moment correlation showed that there was no correlation between LAVI and exercise capacity measured by METS score. CONCLUSION: There is no correlation between LAVI and exercise capacity measured by metabolic equivalents (METS) among post-PCI for myocardial infarction patients. KEYWORDS: left atrial volume index; functional exercise capacity; post-percutaneous coronary intervention

Determining Safe Participation in Aerobic Exercise Early After Stroke Through a Graded Submaximal Exercise Test.

The benefits of aerobic exercise early after stroke are well known, but concerns about cardiovascular risk are a barrier to clinical implementation. Symptom-limited exercise testing with electrocardiography (ECG) is recommended but not always feasible. The purpose of this study was to determine the frequency of and corresponding exercise intensities at which ECG abnormalities occurred during submaximal exercise testing that would limit safe exercise prescription beyond those intensities. This study was a retrospective analysis of ECGs from 195 patients who completed submaximal exercise testing during stroke rehabilitation. A graded submaximal exercise test was conducted with a 5- or 12-lead ECG and was terminated on the basis of predetermined endpoint criteria (heart rate, perceived exertion, signs, or symptoms). ECGs were retrospectively reviewed for exercise-induced abnormalities and their associated heart rates. The peak heart rate achieved was 65.4% (SD=10.5%) of the predicted maximum heart rate or 29.1% (SD=15.5%) of the heart rate reserve (adjusted for beta-blocker medications). The test was terminated more often because of perceived exertion (93/195) than because of heart rate limits (60/195). Four patients (2.1%) exhibited exercise-induced horizontal or downsloping ST segment depression of ≥1mm. Except for 1 patient, the heart rate at test termination was comparable with the heart rate associated with the onset of the ECG abnormality. A graded submaximal exercise test without ECG but with symptom monitoring and conservative heart rate and perceived exertion endpoints may facilitate safe exercise intensities early after stroke. Symptom-limited exercise testing with ECG is still recommended when progressing to higher intensity exercise. Concerns about cardiovascular risk are a barrier to physical therapists implementing aerobic exercise in stroke rehabilitation. This study showed that, in the absence of access to exercise testing with ECG, submaximal testing with conservative heart rate and perceived exertion endpoints and symptom monitoring can support physical therapists in the safe prescription of aerobic exercise early after stroke. It is recommended that people with stroke participate in aerobic exercise as early as possible during their rehabilitation. A submaximal exercise test with monitoring of heart rate, perceived exertion, blood pressure, and symptoms can support physical therapists in safely prescribing that exercise.

Effect of High Intensity Interval Training on Blood Glucose Levels in Type 2 Diabetes

Abstract Background: Patients with type 2 diabetes are at signifi-cantly increased risk for cardiovascular morbidity and mortality compared with age-matched healthy control subjects. Aim of Study: Was to determine the effect of high intensity interval training on blood glucose levels in type 2 diabetes. Subject and Methods: Forty diabetic patients of both sexes (12 males and 28 females). They were assigned into two groups equal in number. All patients were diagnosed clinically with established T2DM for more than 7-year duration. Their ages ranged from 45 to 55 years selected from outpatient clinic of Kasr El-Aini, Cairo University, Egypt. Study group with mean age (51.07±3.31) years. and Control group with mean age (51.36± 2.83 ) years. The study group included 20 patients (7 males and 13 females) who practiced high intensity interval training at intensity level of (85-90% of MHR), three times per week for 12 weeks in addition to their optimized oral hypoglycemic medications. Symptom limited exercise test was performed before and after training (12 weeks) to determine maximum heart rate. The control group included 20 patients (5 males 15 females) who only received their optimized oral hypoglycemic medications. Fasting and post prandial blood glucose were measured initially before starting the treatment and after the end of the sessions in both groups. Results: Post-treatment there were a significant improve-ment in both fating and two hours post prandial blood glucose. There were a significant decrease in fasting and two hours post prandial blood glucose. Conclusion: The high intensity interval training is an effective tool to decrease insulin resistance and hyperglycemia this effect is mediated, in part, by the decrease in fasting and two hours post prandial blood glucose in type 2 diabetic patients which consequently helps in the treatment type 2 diabetes.

0719 The Association of Sleep Apnea and Cardiorespiratory Fitness with Long-Term Major Cardiovascular Events

Abstract Introduction Sleep disordered breathing (SDB) is associated with adverse cardiovascular outcomes and decreased cardiorespiratory fitness (CRF). The risk of long-term major adverse cardiovascular events (MACE) when SDB and decreased CRF co-occur has not been determined. Methods We included consecutive patients that underwent a symptom-limited cardiopulmonary exercise test followed by first-time diagnostic polysomnography within 6 months. Patients were stratified based on the presence of moderate-severe SDB (apnea/hypopnea index ≥15/hour) and decreased CRF defined as &amp;lt;70% predicted peak oxygen consumption (VO2). MACE was a composite outcome of myocardial infarction (MI), coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), stroke/transient ischemic attack (TIA) and death. Cox-proportional hazard models adjusting for factors known to influence CRF and MACE were constructed. Results Of 498 included patients (60±13 years, 28.1% female), 175 (35%) had MACE (MI=17, PCI=14, CABG=13, stroke=20, TIA=12, deaths=99) at a median follow-up of 8.7 years (interquartile range=6.5-10.3 years). After adjusting for age, sex, beta-blockers, systemic hypertension, diabetes mellitus, coronary artery disease, cardiac arrhythmia, chronic obstructive pulmonary disease, smoking and positive airway pressure (PAP) usage, decreased CRF alone (HR=1.91, 95%CI=1.15-3.18, p=0.012), but not SDB alone (HR=1.26, 95%CI=0.75-2.13, p=0.389) was associated with increased risk of MACE. Those with SDB and decreased CRF had increased risk of MACE compared to patients with decreased CRF alone (HR=1.85, 95%CI=1.21-2.84, p&amp;lt;0.005) after accounting for these confounders; the risk was attenuated after additionally adjusting for adequate adherence to PAP (HR=1.85, 95%CI=0.99-3.05, p=0.05). Conclusion The incidence of MACE, including mortality, was high in this sample. Moderate-severe SDB with concurrent decreased CRF was associated with higher risk of MACE than decreased CRF alone. These results highlight the importance of including CRF in the risk assessment of patients with SDB, and conversely, that of screening for SDB in patients with low peak VO2. Support None.

Contributions of residual hypoxemia to exercise hyperventilation in Fontan patients.

ABSTRACTIt is unsettled whether increased exercise ventilation in Fontan subjects is due to increased pulmonary dead space or augmented ventilatory drive. Twenty-six Fontan patients underwent symptom-limited treadmill cardiopulmonary exercise testing. Two groups of age- and sex- matched subjects served as controls: the biventricularly repaired (Bi, n = 18), and the “true” control (C, n = 29) groups. Peak oxygen uptake (V̇O2peak) was not different among groups (41.0 +/– 8.4 ml/min/kg, 43.5 +/– 6.6 ml/min/kg, and 45.9 +/– 11.6 ml/min/kg for Fontan, Bi, and C groups, respectively, p = 0.16). Fontan subjects, however, showed steeper alveolar ventilation/carbon-dioxide (V̇A/V̇CO2) regression slope (35.5 +/– 5.3, 28.7 +/– 3.8, and 29.5 +/– 3.0 l/ml, for Fontan, Bi, and C groups, respectively, p<0.0001), and lower end-expiratory carbon-dioxide fraction (FetCO2VAT) at ventilatory threshold (VAT) (4.4 +/– 0.5%, 5.5 +/– 0.5%, and 5.5 +/– 0.4%, for Fontan, Bi, and C groups, respectively, p<0.001). The dead-space ventilation fraction at VAT was similar among groups (0.33 +/– 0.06, 0.33 +/– 0.04, 0.35 +/– 0.05 for Fontan, Bi, and C groups, respectively, p = 0.54). In Fontan subjects, arterial oxygen saturation at rest (SaO2rest) was correlated with V̇A/V̇CO2 regression slope (r = –0.41, p = 0.04) and with FetCO2VAT (p = –0.53, p<0.01). We conclude that Fontan patients show exercise hyperventilation due to augmented central and/or peripheral ventilatory drive, which is further augmented by residual hypoxemia.

Impact of Right Ventricular Dilatation in Patients with Atrial Septal Defect.

Objective The aim of this study was to examine the relationship between right ventricular (RV) volume and exercise capacity in adult patients with atrial septal defect (ASD) and to determine the degree of RV dilatation for transcatheter ASD closure. Background RV dilatation is an indication of transcatheter ASD closure; however, few studies have reported the clinical significance of RV dilatation. Methods We enrolled 82 consecutive patients (mean age, 49 ± 18 years; female, 68%) who underwent cardiac magnetic resonance imaging and symptom-limited cardiopulmonary exercise test before ASD closure. The relationship between RV volume and peak oxygen uptake (VO2) was evaluated. Results The mean RV end-diastolic volume index was 108 ± 27 ml/m2 (range, 46 to 180 ml/m2). The mean peak VO2 was 24 ± 7 ml/min/kg (range, 14 to 48 ml/min/kg), and the mean predicted peak VO2 was 90 ± 23%. There were significant negative relationships of RV end-diastolic volume index with peak VO2 (r = −0.28, p < 0.01) and predicted peak VO2 (r = −0.29, p < 0.01). The cutoff value of RV end-diastolic volume index <80% of predicted peak VO2 was 120 ml/m2, with the sensitivity of 49% and the specificity of 89%. Conclusions There was a relationship between RV dilatation and exercise capacity in adult patients with ASD. RV end-diastolic volume index ≥120 ml/m2 was related to the reduction in peak VO2. This criterion of RV dilatation may be valuable for the indication of transcatheter ASD closure.

The Personalized Precise Exercise Training Holistic Integrative Protocol (PPET‐HIP) for Patient with Myocardial Incompetence and Catecholamine‐Sensitive Ventricular Arrhythmia after her Sudden Cardiac Arrest

INTRODUCTIONSThe patient was a 23yrs female nurse in Fuwai‐hospital. After 2d overtime work, she had suddenly cardiac arrested followed by successful CPR and 5hr unconsciousness. Afterward she was diagnosed as catecholamine‐sensitive ventricular tachycardia, myocardial insufficiency and etc; and some physicians suggested installing of cardiac pacemaker with ICD. However, based on HIPM, we believe her main problem was the mismatching of supply‐demand and poor integration among systems, and Personalized Precise exercise Training Holistic Integrative Protocol (PPET‐HIP)can reverse those. We suggested give us ~100d PPET‐HIP and then decide for pacemaker‐ICD.METHODSAfter performing symptom limited maximum cardiopulmonary exercise testing (CPET) for objectively quantitative evaluation, we generated her PPET‐HIPΔ50% Power for intensity titration. According to results of continuous beat‐by‐beat blood pressure and continuous blood glucose monitoring during 30min Δ50% Power intensity titration we did select qid, 6d/w intensive management.RESULTSAfter 1m of intensive management, her continuation duration of PPET‐HIP was increased from 1–2min to 6–7min. The total exercise duration was increased from 17 to 24min, and resting was decreased from 8–10 to 3–4 times/30min. In 1st CPET, ventricular premature (PVC) began from loading intensity over 75w/min until peak loading127.5W/min , and total PVC was 119beat/130s.After three‐month PPET‐HIP,CPET showed PVC began from loading intensity over 100w/min until peak loading 162.5W/min , and total PVC was 68beat/170s. Comparing with the 1st one, three‐month CPET’s key parameters of peakVO2, AT, peak loading, peak CO and oxygen uptake efficiency plateau (OUEP) were increased by 20.1%, 15.2%, 21.5% and 22.5%, 21.7% and 5.7% respectively, only VE/VCO2 was decreased by 5.4%; all indicated improvement of functional status. The she has been believed that she couldn’t be nursing work again. However, after leaving Fuwai, she has become a clinical nurse again and working in cardiac rehabilitation, which is very meaningful for her.CONCLUSION Under the guidance of HIPM, we could safely and effectively manage patients by PPET‐HIP. Increased functional capacity parameters in CPET by 5–23%. Increased threshold of PVC and decreased rate of PVC during CPET. Decreased number of PVC and decreased rate of PVC in 30min training of PPET‐HIP.Support or Funding InformationNational Natural Science Foundation of China (81470204);Fuwai Hospital, National Cardiovascular Institute of Chinese Academy of Medical Sciences (2012‐YJR02);Research on Clinical Characteristics of the Capital (Z141107002514084);Research and Outcome Promotion of Clinical Characteristics in the Capital (Project No. Z161100000516127)

Difference in prevalence of exertional oscillatory ventilation between healthy subjects and patients with cardiovascular disease.

Exercise oscillatory ventilation (EOV) is an ominous sign in heart failure due to reduced left ventricular ejection fraction (HFrEF) whatever it is represented. But EOV is detected also in normal healthy individuals and in other cardiovascular disease (CVD) patients, however, its prevalence in these is not completed clear. The aim was to describe the occurrence of EOV in healthy subjects and the overall population all CVD patients who performing symptom limited cardiopulmonary exercise testing (CPET). Healthy subjects were divided in athletes and normal subjects, while, CVD patients were subdivided into: i) t hose with preserved left ventricular ejection fraction (LVEF); ii) those with mild to moderate impairment of LVEF (41-49%); iii) those with severe impairment of LVEF (≤40%); iv) HFrEF or with preserved LVEF (HFpEF); and iv) patients after heart transplantation (HXT). EOV was observed only in CVD patients and in those with depressed LVEF; the prevalence of EOV was observed 1.9% (3/55) those with mild to moderate impairment of LVEF (41-49%), 3.4% (56/1613) those with severe impairment of LVEF (≤40%), and 7.3% (214/2903) in HFrEF); no EOV was observed in CVD with preserved LVEF. Kremser's EOV was observed in patients, and, particularly, in those with systolic function impairment. Moreover, as EOV impacts prognosis in HFrEF, its occurrence can modify prognostic-decision models. Even though, EOV prevalence was derived from largest single center population, more studies are needed to tackle the EOV prevalence in different CVD conditions and in normal subjects.

Changes in oxygen uptake kinetics after exercise caused by differences in loading pattern and exercise intensity.

AimsThe kinetics of recovery‐period oxygen uptake (VO2) are affected by the O2 deficit generated during exercise. However, studies using ramp tests (RTs) and constant work rate tests (CT) have differently characterized VO2 responses to increased exercise intensity differently. We used these two types of loading patterns to investigate the effects of low‐intensity, medium‐intensity, and high‐intensity exercises on the half time (T1/2) of recovery‐period VO2 and the mechanism.Methods and resultsTen healthy men aged 21.2 ± 0.9 years underwent symptom‐limited cardiopulmonary exercise tests with the ramp protocol to determine their anaerobic threshold. All subjects subsequently underwent three submaximal RT and CT at low, moderate, and high intensities. In all RTs, subjects began exercise by warming up (20 W). In CT, T1/2 was significantly lengthened as exercise intensity increased (CT‐low: 34.0 ± 3.9 s, CT‐moderate: 39.5 ± 3.5 s, CT‐high:44.6 ± 4.2 s; P < 0.01, ANOVA), whereas no significant change was observed in RT, which began with the same work rate (RT‐low: 46.0 ± 5.7 s, RT‐moderate: 45.7 ± 4.8 s, RT‐high: 44.6 ± 3.5 s, RT‐max: 44.8 ± 3.2 s; P = 0.868, ANOVA). Only high‐intensity exercise resulted in two components (the fast and slow components) of VO2 decay, reflecting the increased O2 deficit by anaerobic metabolism.ConclusionsThe exercise intensity at the beginning of an exercise affects early recovery‐period VO2, which is a fast component. The T1/2 of recovery‐period VO2 occurs during the fast component, and an increase in O2 deficit affects both the fast and slow components, lengthening the T1/2. The T1/2 of recovery‐period VO2 in CT at moderate or high intensities, even if not symptom limited, can be used to evaluate exercise intolerance and early occurrence of anaerobic metabolism. Submaximal exercise tests may be considered as convenient methods for evaluating exercise tolerance in patients with cardiac failure.

Ventilatory compensation during the incremental exercise test is inversely correlated with air trapping in COPD.

Background: Air trapping and gas exchange abnormalities are major causes of exercise limitation in chronic obstructive pulmonary disease (COPD). During incremental cardiopulmonary exercise testing, actual nadir values of ventilatory equivalents for carbon dioxide (V E/VCO 2) and oxygen (V E/VO 2) may be difficult to identify in COPD patients because of limited ventilatory compensation capacity. Therefore, we aimed in this exploratory study to detect a possible correlation between the magnitude of ventilation augmentation, as manifested by increments in ventilatory equivalents from nadir to peak exercise values and air trapping, detected with static testing. Methods: In this observational study, we studied data obtained previously from 20 COPD patients who, during routine follow-up, underwent a symptom-limited incremental exercise test and in whom a plethysmography was obtained concurrently. Air trapping at rest was assessed by measurement of the residual volume (RV) to total lung capacity (TLC) ratio (RV/TLC). Gas exchange data collected during the symptom-limited incremental cardiopulmonary exercise test allowed determination of the nadir and peak exercise values of V E/VCO 2 and V E/VO 2, thus enabling calculation of the difference between peak exrcise value and nadir values of V E/VCO 2 and V E/VO 2, designated ΔV E/VCO 2 and ΔV E/VO 2, respectively. Results: We found a statistically significant inverse correlation between both ΔV E/VCO 2 (r = -0. 5058, 95% CI -0.7750 to -0.08149, p = 0.0234) and ΔV E/VO 2 (r = -0.5588, 95% CI -0.8029 to -0.1545, p = 0.0104) and the degree of air trapping (RV/TLC). There was no correlation between ΔV E/VCO 2 and forced expiratory volume in the first second, or body mass index. Conclusions: The ventilatory equivalents increment to compensate for acidosis during incremental exercise testing was inversely correlated with air trapping (RV/TLC).

Subclinical Inflammation Is Associated With Reductions in Muscle Oxygenation, Exercise Capacity and Quality of Life in Adults With Type 2 Diabetes

ObjectivesExercise capacity is related to both morbidity and mortality in patients with type 2 diabetes (T2DM). The aim of this study was to investigate the relationship between subclinical inflammation level, exercise capacity, muscle oxygenation and quality of life in T2DM. MethodsThis study includes 28 patients with T2DM (mean age, 51.5±5.0 years; male-to-female ratio, 6:22). Exercise capacity was evaluated using an incremental symptom-limited maximal exercise test on a bicycle ergometer. Muscle oxygenation was investigated using a wearable lactate-measuring device. Diabetes-specific quality of life was assessed using the Diabetes Quality of Life Questionnaire (DQOL). Subclinical inflammation was assessed using C-reactive protein (CRP) levels. ResultsCRP level was negatively correlated with peak workload during the test (r=–0.588, p=0.002), muscle oxygenation (r=–0.465, p=0.019) and the psychological impact of treatment subscale of the DQOL (r=–0.540, p=0.017), and positively correlated with body mass index (r=0.519, p=0.008), waist circumference (r=0.426, p=0.038) and fat percentage (r=0.573, p=0.004). There was no correlation between CRP and fasting blood glucose or glycated hemoglobin level (p>0.05). Peak workload was inversely related to fat percentage (r=–0.467, p=0.016) and the DQOL worry about the future impact of diabetes subscale (r=–0.501, p=0.021). ConclusionsIn our study, subclinical inflammation negatively affected muscle oxygenation, exercise capacity and quality of life independently of glycemic indicators. Our findings suggest that the degree of glycemic control is insufficient to explain lower exercise capacity. Further studies are needed to investigate subclinical inflammation-reducing interventions in T2DM.

Ventilatory compensation during the incremental exercise test is inversely correlated with air trapping in COPD

Background: Air trapping and gas exchange abnormalities are major causes of exercise limitation in chronic obstructive pulmonary disease (COPD). During incremental cardiopulmonary exercise testing, actual nadir values of ventilatory equivalents for carbon dioxide (V E/VCO 2) and oxygen (V E/VO 2) may be difficult to identify in COPD patients because of limited ventilatory compensation capacity. Therefore, we aimed in this exploratory study to detect a possible correlation between the magnitude of ventilation augmentation, as manifested by increments in ventilatory equivalents from nadir to peak exercise values and air trapping, detected with static testing. Methods: In this observational study, we studied data obtained previously from 20 COPD patients who, during routine follow-up, underwent a symptom-limited incremental exercise test and in whom a plethysmography was obtained concurrently. Air trapping at rest was assessed by measurement of the residual volume (RV) to total lung capacity (TLC) ratio (RV/TLC). Gas exchange data collected during the symptom-limited incremental cardiopulmonary exercise test allowed determination of the nadir and peak exercise values of V E/VCO 2 and V E/VO 2, thus enabling calculation of the difference between peak exrcise value and nadir values of V E/VCO 2 and V E/VO 2, designated ΔV E/VCO 2 and ΔV E/VO 2, respectively. Results: We found a statistically significant inverse correlation between both ΔV E/VCO 2 (r = -0. 5058, 95% CI -0.7750 to -0.08149, p = 0.0234) and ΔV E/VO 2 (r = -0.5588, 95% CI -0.8029 to -0.1545, p = 0.0104) and the degree of air trapping (RV/TLC). There was no correlation between ΔV E/VCO 2 and forced expiratory volume in the first second, or body mass index. Conclusions: The ventilatory equivalents increment to compensate for acidosis during incremental exercise testing was inversely correlated with air trapping (RV/TLC).

Association of Simple Step Test With Readiness for Exercise in Youth After Concussion.

We hypothesized that a submaximal step test would be associated with readiness to commence graded exercise in children and adolescents with concussion. Children and adolescents aged 8 to 18 years performed standard concussion clinical assessment for vestibular/ocular and balance impairment, and exercise examination utilizing the 3-minute Kasch Pulse Recovery test (KPR) and a symptom-limited graded exercise test (GXT). Outcome measures included activity readiness and symptom exacerbation. Forty-five participants (mean age 13.2 ± 2.1 years, 76% male) had a confirmed concussion (73% sports-related). Some participants required follow-up testing giving 75 clinical presentations. Sensitivity and specificity of the KPR were 100% and 95.7%, respectively. Area under the receiver operating characteristics curve was 0.979. Activity readiness to GXT and KPR was strongly associated (χ = 21.672, P < .001), while symptom exacerbation showed a significant correlation between testing methods (r = 0.796, P < .001). Better exercise performance on GXT and KPR was significantly correlated with normal Vestibular/Ocular Motor Screening (rs = -0.380, P = .010, and rs = -0.281, P = .017, respectively) and Modified Balance Error Scoring System (rs = -0.452, P < .001, and rs = -0.301, P = .010, respectively). The KPR is a simple and practical tool to determine whether it is appropriate for a child or adolescent with concussion to commence graded exercise.