Search

Aim: Poor cardiorespiratory fitness has been suggested to increase the risk of chronic diseases in obesity. We investigated the ability of key variables from cardiopulmonary exercise testing (CPET) to predict all‐cause mortality in an obese cohort. Methods: The sample included 469 participants of both sexes (mean age 40 ± 13 years) who underwent a CPET for clinical reasons between 1 March 2009 and 1 December 2023. All‐cause mortality was the prognostic endpoint. A receiver operating characteristic analysis was performed to establish optimal cut‐points for CPET variables. Kaplan–Meier and Cox regression analyses were used to determine the association between CPET variables and all‐cause mortality. Results: There were 46 deaths during a mean follow‐up period of 69 ± 48 months, resulting in an annual mortality rate of 2%. Despite the sample being made up of mostly women (70%), there were more deaths in men (18 vs. 6%, p < 0.001).The optimal thresholds for discrimination of survival were as follows: (a) peak oxygen uptake (pVO2) ≤16 mL/kg/min; (b) minute ventilation/carbon dioxide production (VE/VCO2) slope ≥31; (c) ventilatory power ≤5.8 mmHg; and (d) circulatory power ≤2980 mmHg/mL O2/min. Kaplan–Meier survival plots revealed a significant positive association between lower pVO2, circulatory power and ventilatory power values and survival (log‐rank, p < 0.001) and higher mortality for men than women. Adjusted Cox regression models showed that a pVO2 ≤16 mL/kg/min had a 20‐fold higher risk of mortality when compared with >16 mL/kg/min. Conclusion: Given the strong association of VO2, ventilatory efficiency, circulatory and ventilatory power with all‐cause mortality, our findings support the notion that poorer cardiorespiratory fitness is associated with a poor prognosis in patients with obesity. [ABSTRACT FROM AUTHOR]

Considerable and convincing global data from cohorts across the health spectrum (i.e. apparently healthy to known disease) indicate that cardiorespiratory fitness (CRF) is a major predictor of overall and cardiovascular disease (CVD)-survival, seemingly with greater prognostic resolution compared to other traditional CVD risk factors. Therefore, the assessment of CRF in research and clinical settings is of major importance. In this manuscript, we review the technology of measuring CRF assessed by the 'gold standard,' cardiopulmonary exercise testing (CPET), as well as with various other methods (e.g. estimated metabolic equivalents, 6-minute walk tests, shuttle tests, and non-exercise equations that estimate CRF), all of which provide significant prognostic information for CVD- and all-cause survival. The literature through May 2024 has been cited. The promotion of physical activity in efforts to improve levels of CRF is needed throughout the world to improve lifespan and, more importantly, healthspan. The routine assessment of CRF should be considered a vital sign that is routinely assessed in clinical practice. [ABSTRACT FROM AUTHOR]

This review emphasizes the importance of cardiopulmonary exercise testing (CPET) in patients diagnosed with hypertrophic cardiomyopathy (HCM). In contrast to standard exercise testing and stress echoes, which are limited due to the ECG changes and wall motion abnormalities that characterize this condition, CPET allows for the assessment of the complex pathophysiology and severity of the disease, its mechanisms of functional limitation, and its risk stratification. It is useful tool to evaluate the risk for sudden cardiac death and select patients for cardiac resynchronization therapy (CRT), cardiac transplantation, or mechanical circulatory support, especially when symptomatology and functional status are uncertain. It may help in differentiating HCM from other forms of cardiac hypertrophy, such as athletes' heart. Finally, it is used to guide and monitor therapy as well as for exercise prescription. It may be considered every 2 years in clinically stable patients or every year in patients with worsening symptoms. Although performed only in specialized centers, CPET combined with echocardiography (i.e., CPET imaging) and invasive CPET are more informative and provide a better assessment of cardiac functional status, left ventricular outflow tract obstruction, and diastolic dysfunction during exercise in patients with HCM. [ABSTRACT FROM AUTHOR]

BACKGROUND: We sought to assess whether noninvasive ventilation (NIV) as an adjunct with high-intensity exercise (HIEx) is more effective than exercise alone or exercise + sham on respiratory and peripheral oxygenation and vascular function in subjects with coexisting COPD and heart failure (HF). METHODS: On separate days, subjects performed incremental cardiopulmo-nary exercise testing and 3 constant load tests: HIEx, HIEx+NIV, and HIEx+sham (bi-level mode, Astral 150). Subjects were randomized with a 1:1 block allocation for the HIEx+NIV group and HIEx+sham group until the limit of tolerance (Tlim). Peripheral and respiratory oxy-genation were assessed by oxyhemoglobin (O2Hb) and deoxyhemoglobin (Hb) using near-infrared spectroscopy in the respiratory and peripheral musculature. Vascular function was assessed by endothelial function using the flow-mediated vasodilation (FMD) method. RESULTS: There was a significant increase in FMD (mm), FMD (%), and shear stress in the HIEx+NIV group when compared to HIEx or HIEx+sham (P < .05). Less extraction of O2 (Hb) in the peripheral and respiratory muscles was observed in the HIEx+NIV group (P < .05). We also found correlations between peripheral muscle oxygenation (O2Hb) at the moment 80% of Tlim (r = 0.71, P = .009) and peak of Tlim (100%) (r = 0.76, P = .004) with absolute FMD (mm) immediately after HIEx+NIV. CONCLUSIONS: NIV as an adjunct to HIEx can acutely unload the respiratory musculature with better redistribution of available blood flow and beneficially modulate endo-thelial function. These results may influence the approach to cardiopulmonary rehabilitation in patients with coexisting COPD-HF. [ABSTRACT FROM AUTHOR]

Introduction: Peak rating of perceived exertion (RPE) is measured during clinical cardiopulmonary exercise testing (CPX) and is commonly used as a subjective indicator of maximal effort. However, no study to date has reported reference standards or the distribution of peak RPE across a large cohort of apparently healthy individuals. Purpose: This study aimed to determine reference standards for peak RPE when using the 6–20 Borg scale for both treadmill and cycle tests. Methods: The analysis included 9551 tests (8821 treadmill, 730 cycle ergometer) from 13 laboratories within the Fitness Registry and Importance of Exercise National Database (FRIEND). Using data from tests conducted January 1, 1980, to January 1, 2021, percentiles of peak RPE for men and women were determined for each decade from 20 to 89 yr of age for treadmill and cycle exercise modes. Two-way ANOVA was used to compare differences in peak RPE values between sexes and across age groups. Results: There were statistically significant differences in RPE between age groups whether the test was performed on a treadmill or cycle ergometer (P < 0.05). However, the mean and median RPE for each sex, age group, and test mode were between 18 and 19. In addition, 83% of participants met the traditional RPE criteria of ≥18 for indicating sufficient maximal effort. Conclusions: This report provides the first normative reference standards for peak RPE in both male and female individuals performing CPX on a treadmill or cycle ergometer. Furthermore, these reference standards highlight the general consistency of peak RPE responses during CPX. [ABSTRACT FROM AUTHOR]

Purpose: Poor cardiorespiratory fitness is associated with increased all cause morbidity and mortality. In children with obesity, maximum oxygen uptake (...O2max) may not be achieved due to reduced motivation and peripheral fatigue. We aimed to identify a valid submaximal surrogate for ...O2max in children with obesity. Method: Ninety-two children with obesity (7-16 years) completed a maximal exercise treadmill test and entered a three-month exercise and/or nutrition intervention after which the exercise test was repeated (n = 63). Participants were required to reach ...O2max to be included in this analysis (n = 32 at baseline and n = 13 at both time-points). The oxygen uptake efficiency slope (OUES) was determined as the slope of the line when ...O2 (L/min) was plotted against log...E. Associations between the maximal OUES, submaximal OUES (at 3, 4, 5 and 6 min of the exercise test) and ...O2max were calculated. Results: In the cross-sectional analysis, ...O2max (L/min) was strongly correlated with 5-min OUES independent of Tanner puberty stage and sex (R² = .80, p < .001). Longitudinal changes in ...O2max were closely reflected by changes in 5-min OUES independent of change in percent body fat (R² = .63, p < .05). Conclusion: The 5-min OUES is a viable alternative to ...O2max when assessing children with obesity. [ABSTRACT FROM AUTHOR]

Our aim was to evaluate: (1) the prevalence of coexistence of heart failure (HF) and chronic obstructive pulmonary disease (COPD) in the studied patients; (2) the impact of HF + COPD on exercise performance and contrasting exercise responses in patients with only a diagnosis of HF or COPD; and (3) the relationship between clinical characteristics and measures of cardiorespiratory fitness; (4) verify the occurrence of cardiopulmonary events in the follow-up period of up to 24 months years. The current study included 124 patients (HF: 46, COPD: 53 and HF + COPD: 25) that performed advanced pulmonary function tests, echocardiography, analysis of body composition by bioimpedance and symptom-limited incremental cardiopulmonary exercise testing (CPET) on a cycle ergometer. Key CPET variables were calculated for all patients as previously described. The V ˙ E/ V ˙ CO2 slope was obtained through linear regression analysis. Additionally, the linear relationship between oxygen uptake and the log transformation of V ˙ E (OUES) was calculated using the following equation: V ˙ O2 = a log V ˙ E + b, with the constant 'a' referring to the rate of increase of V ˙ O2. Circulatory power (CP) was obtained through the product of peak V ˙ O2 and peak systolic blood pressure and Ventilatory Power (VP) was calculated by dividing peak systolic blood pressure by the V ˙ E/ V ˙ CO2 slope. After the CPET, all patients were contacted by telephone every 6 months (6, 12, 18, 24) and questioned about exacerbations, hospitalizations for cardiopulmonary causes and death. We found a 20% prevalence of HF + COPD overlap in the studied patients. The COPD and HF + COPD groups were older (HF: 60 ± 8, COPD: 65 ± 7, HF + COPD: 68 ± 7). In relation to cardiac function, as expected, patients with COPD presented preserved ejection fraction (HF: 40 ± 7, COPD: 70 ± 8, HF + COPD: 38 ± 8) while in the HF and HF + COPD demonstrated similar levels of systolic dysfunction. The COPD and HF + COPD patients showed evidence of an obstructive ventilatory disorder confirmed by the value of %FEV1 (HF: 84 ± 20, COPD: 54 ± 21, HF + COPD: 65 ± 25). Patients with HF + COPD demonstrated a lower work rate (WR), peak oxygen uptake ( V ˙ O2), rate pressure product (RPP), CP and VP compared to those only diagnosed with HF and COPD. In addition, significant correlations were observed between lean mass and peak V ˙ O2 (r: 0.56 p < 0.001), OUES (r: 0.42 p < 0.001), and O2 pulse (r: 0.58 p < 0.001), lung diffusing factor for carbon monoxide (DLCO) and WR (r: 0.51 p < 0.001), DLCO and VP (r: 0.40 p: 0.002), forced expiratory volume in first second (FEV1) and peak V ˙ O2 (r: 0.52; p < 0.001), and FEV1 and WR (r: 0.62; p < 0.001). There were no significant differences in the occurrence of events and deaths contrasting both groups. The coexistence of HF + COPD induces greater impairment on exercise performance when compared to patients without overlapping diseases, however the overlap of the two diseases did not increase the probability of the occurrence of cardiopulmonary events and deaths when compared to groups with isolated diseases in the period studied. CPET provides important information to guide effective strategies for these patients with the goal of improving exercise performance and functional capacity. Moreover, given our findings related to pulmonary function, body composition and exercise responses, evidenced that the lean mass, FEV1 and DLCO influence important responses to exercise. [ABSTRACT FROM AUTHOR]

Anticipation of stress induces physiological, behavioral and cognitive adjustments that are required for an appropriate response to the upcoming situation. Additional research examining the response of cardiopulmonary parameters and stress hormones during anticipation of stress in different chronic stress adaptive models is needed. As an addition to our previous research, a total of 57 subjects (16 elite male wrestlers, 21 water polo player and 20 sedentary subjects matched for age) were analyzed. Cardiopulmonary exercise testing (CPET) on a treadmill was used as the laboratory stress model; peak oxygen consumption (VO2) was obtained during CPET. Plasma levels of adrenocorticotropic hormone (ACTH), cortisol, alpha-melanocyte stimulating hormone (alpha-MSH) and N-terminal-pro-B type natriuretic peptide (NT-pro-BNP) were measured by radioimmunometric, radioimmunoassay and immunoassay sandwich technique, respectively, together with cardiopulmonary measurements, 10 minutes pre-CPET and at the initiation of CPET. The response of diastolic blood pressure and heart rate was different between groups during stress anticipation (p=0.019, 0.049, respectively), while systolic blood pressure, peak VO2 and carbon-dioxide production responses were similar. ACTH and cortisol increased during the experimental condition, NT-pro-BNP decreased and alpha-MSH remained unchanged. All groups had similar hormonal responses during stress anticipation with the exception of the ACTH/cortisol ratio. In all three groups, DNT-pro-BNP during stress anticipation was the best independent predictor of peak VO2 (B=36.01, r=0.37, p=0.001). In conclusion, the type of chronic stress exposure influences the hemodynamic response during anticipation of physical stress and the path of hormonal stress axis activation. Stress hormones released during stress anticipation may hold predictive value for overall cardiopulmonary performance during the stress condition. [ABSTRACT FROM AUTHOR]

To achieve this with an appropriately powered sample size, an international registry that includes high-quality CPX laboratories conducting tests in patients with COVID-19 and tracking outcomes would be ideal. Pleguezuelos et al. [[8]] performed CPX on healthy controls, patients diagnosed with ischemic heart disease (IHD), patients diagnosed with chronic obstructive pulmonary disease (COPD) and patients hospitalized for COVID-19; CPX was performed two months post-hospital discharge in the COVID-19 group. Keywords: Aerobic capacity; cardiorespiratory fitness; prognosis; pulmonary hemodynamics; ventilatory efficiency EN Aerobic capacity cardiorespiratory fitness prognosis pulmonary hemodynamics ventilatory efficiency 877 880 4 11/30/21 20211001 NES 211001 Countries around the world continue to address the large-scale health and wellbeing impacts and the broader societal burden associated with the coronavirus disease 2019 (COVID-2019). [Extracted from the article]

Background: Understanding the basis of the phenotypic variation in Gaucher's disease (GD) has proven to be challenging for efficient treatment. The current study examined cardiopulmonary characteristics of patients with GD type 1. Methods: Twenty Caucasian subjects (8/20 female) with diagnosed GD type I (GD‐S) and 20 age‐ and sex‐matched healthy controls (C), were assessed (mean age GD‐S: 32.6 ± 13.1 vs. C: 36.2 ± 10.6, p >.05) before the initiation of treatment. Standard echocardiography at rest was used to assess left ventricular ejection fraction (LVEF) and pulmonary artery systolic pressure (PASP). Cardiopulmonary exercise testing (CPET) was performed on a recumbent ergometer using a ramp protocol. Results: LVEF was similar in both groups (GD‐S: 65.1 ± 5.2% vs. C: 65.2 ± 5.2%, p >.05), as well as PAPS (24.1 ± 4.2 mmHg vs. C: 25.5 ± 1.3 mmHg, p >.05). GD‐S had lower weight (p <.05) and worse CPET responses compared to C, including peak values of heart rate, oxygen consumption, carbondioxide production (VCO2), end‐tidal pressure of CO2, and O2 pulse, as well as HR reserve after 3 min of recovery and the minute ventilation/VCO2 slope. Conclusions: Patients with GD type I have an abnormal CPET response compared to healthy controls likely due to the complex pathophysiologic process in GD that impacts multiple systems integral to the physiologic response to exercise. Our study demonstrate that patients with Gaucher's disease (GD) type I have an abnormal Cardiopulmonary exercise testing response compared to healthy controls. These findings are likely due to the complex pathophysiologic process in GD that impacts multiple systems integral to the physiologic response to exercise. [ABSTRACT FROM AUTHOR]

Background: Respiratory muscle unloading through proportional assist ventilation (PAV) may enhance leg oxygen delivery, thereby speeding off-exercise oxygen uptake ( V. ⁢ O 2 ) kinetics in patients with heart failure with reduced left ventricular ejection fraction (HFrEF). Methods: Ten male patients (HFrEF = 26 ± 9%, age 50 ± 13 years, and body mass index 25 ± 3 kg m2) underwent two constant work rate tests at 80% peak of maximal cardiopulmonary exercise test to tolerance under PAV and sham ventilation. Post-exercise kinetics of V. ⁢ O 2 , vastus lateralis deoxyhemoglobin ([deoxy-Hb + Mb]) by near-infrared spectroscopy, and cardiac output (Q T ) by impedance cardiography were assessed. Results: PAV prolonged exercise tolerance compared with sham (587 ± 390 s vs. 444 ± 296 s, respectively; p = 0.01). PAV significantly accelerated V. ⁢ O 2 recovery (τ = 56 ± 22 s vs. 77 ± 42 s; p < 0.05), being associated with a faster decline in Δ[deoxy-Hb + Mb] and Q T compared with sham (τ = 31 ± 19 s vs. 42 ± 22 s and 39 ± 22 s vs. 78 ± 46 s, p < 0.05). Faster off-exercise decrease in Q T with PAV was related to longer exercise duration (r = −0.76; p < 0.05). Conclusion: PAV accelerates the recovery of central hemodynamics and muscle oxygenation in HFrEF. These beneficial effects might prove useful to improve the tolerance to repeated exercise during cardiac rehabilitation. [ABSTRACT FROM AUTHOR]

Cardiorespiratory fitness (CRF) is now established as a vital sign. Cardiopulmonary exercise testing (CPX) is the gold-standard approach to assessing CRF. A body of literature spanning several decades clearly supports the clinical utility of CPX in those who are apparently health and at risk for chronic disease as well as numerous patient populations. While CPX, in and of itself, is a valid and reliable clinical assessment, combining findings with other available assessments may provide a more comprehensive perspective that enhances clinical decision making and outcomes. The current review will accomplish the following: (1) define key CPX measures based upon current evidence; and (2) describe the current evidence addressing the relationships between CPX and echocardiography, serum biomarkers, and cardiovascular magnetic resonance. Cardiopulmonary exercise testing provides prognostic and diagnostic information in apparently healthy individuals, those at risk for one or more chronic conditions, as well as numerous patient populations. Moreover, if the goal of an intervention is to improve one or more systems integral to the physiologic response to exercise, CPX should be considered as a central assessment to gauge therapeutic efficacy. To further refine the information obtained from CPX, combining other assessments has demonstrated promise. [ABSTRACT FROM AUTHOR]

Background: Circulatory (CP) and ventilatory power (VP) have been used to improve the prognostic accuracy of cardiopulmonary exercise tests in cardiovascular disease, such as coronary artery disease. However, the effects of combined resistance and aerobic exercise program on VP and CP, especially in type 2 diabetes patients, have not been adequately investigated. Thus, this new parameter can be useful to prescribe exercise programs more assertive for this population. The present study aimed to assess the effect of 3 months of combined resistance and aerobic exercise training (CET) on CP and VP in patients with type 2 diabetes. Methods: A randomized controlled trial was conducted involving 48 diabetic patients with an average age of 52.4 (±8.01) years old. The subjects were randomized into two groups: sedentary (SG, n = 15) and the CET group (n = 19). Cardiopulmonary exercise testing (symptom‐limited incremental) was performed on a cycle ergometer, and the following parameters were measured: relative VO2, VE/VCO2 slope, linear relationship between oxygen uptake and minute ventilation, and VCO2. CET was performed with 30‐min aerobic and 30‐min resistance exercises three times a week for 12 weeks. Results: Significant (p <.05) and clinical (d ≥.80) differences were observed that favoured CET compared with SG for the following variables: heart rate, workload, VO2 relative peak, circulatory power peak, and VCO2 peak. Although no statistical difference was observed for ventilatory power, there was a clinical difference (p >.05 and d ≥ 0.80) that favoured CET. Conclusion: Three months of combined exercise training improved VP and CP indices in patients with type 2 diabetes when compared with a sedentary group. [ABSTRACT FROM AUTHOR]

Background: Established reference standards for the ventilatory threshold (Vt) are lacking. The aim of this study was to develop reference standards for the Vt derived from cardiopulmonary exercise testing (CPX) using treadmill and cycle ergometry.Methods: Seven laboratories experienced in CPX administration with established quality control procedures contributed to the Fitness Registry and the Importance of Exercise: A National Database (FRIEND) from April 2014 through February 2019. Vt data from 27 states in the United States and the Ontario Province in Canada, comprising 9,350 tests (treadmill: n = 1,195; cycle ergometer: n = 8,155) in men (n = 7,540) and women (n = 1,810) 20 to 79 years of age who were free from smoking and known cardiovascular, pulmonary, metabolic, and/or neoplastic disease were used to develop the reference standards. Comparisons of Vt values were made between exercise testing modes, sex, and age groups.Results: Vt values on the treadmill were higher than cycle ergometry; men had higher Vt values than women on both test modalities, and the highest Vt values achieved were in the 20- to 29-year-old age group compared with all other age groups (all P < .001). The rates of decline in Vt values from age groups 20 to 29 through 70 to 79 years of age were 23% and 35% in men and 47% and 30% in women for treadmill and cycle ergometry tests, respectively.Conclusions: In addition to previous reference standards from FRIEND for cardiorespiratory fitness, the Vt reference standards reported herein provide valuable information on functional metric. These data have important implications for CPX interpretation and aerobic exercise prescription in the clinical and fitness settings. [ABSTRACT FROM AUTHOR]

Introduction. Expiratory flow limitation (EFL) during moderate intensity exercise is present in patients with myocardial infarction (MI), whereas in healthy subjects it occurs only at a high intensity. However, it is unclear whether this limitation already manifests in those with stable coronary artery disease (CAD) (without MI). Materials and Methods. Forty-one men aged 40–65 years were allocated into (1) recent MI (RMI) group (n = 8), (2) late MI (LMI) group (n = 12), (3) stable CAD group (n = 9), and (4) healthy control group (CG) (n = 12). All participants underwent two cardiopulmonary exercise tests at a constant workload (moderate and high intensity), and EFL was evaluated at the end of each exercise workload. Results. During moderate intensity exercise, the RMI and LMI groups presented with a significantly higher number of participants with EFL compared to the CG (p < 0.05), while no significant difference was observed among groups at high intensity exercise (p > 0.05). Moreover, EFL was only present in MI groups during moderate intensity exercise, whereas at high intensity all groups presented EFL. Regarding the degree of EFL, the RMI and LMI groups showed significantly higher values at moderate intensity exercise in relation to the CG. At high intensity exercise, significantly higher values for the degree of EFL were observed only in the LMI group. Conclusion. The ventilatory limitation at moderate intensity exercise may be linked to the pulmonary consequences of the MI, even subjects with preserved cardiac and pulmonary function at rest, and not to CAD per se. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to investigate the ability of oxygen uptake kinetics to predict short-term outcomes after off-pump coronary artery bypass grafting. Methods: Fifty-two patients aged 60.9 ± 7.8 years waiting for off-pump coronary artery bypass surgery were evaluated. The 6-min walk test distance was performed pre-operatively, while simultaneously using a portable cardiopulmonary testing device. The transition of oxygen uptake kinetics from rest to exercise was recorded to calculate oxygen uptake kinetics fitting a monoexponential regression model. Oxygen uptake at steady state, constant time, and mean response time corrected by work rate were analysed. Short-term clinical outcomes were evaluated during the early post-operative of off-pump coronary artery bypass surgery. Results: Multivariate analysis showed body mass index, surgery time, and mean response time corrected by work rate as independent predictors for short-term outcomes. The optimal mean response time corrected by work rate cut-off to estimate short-term clinical outcomes was 1.51 × 10−3 min2/ml. Patients with slower mean response time corrected by work rate demonstrated higher rates of hypertension, diabetes, EuroSCOREII, left ventricular dysfunction, and impaired 6-min walk test parameters. The per cent-predicted distance threshold of 66% in the pre-operative was associated with delayed oxygen uptake kinetics. Conclusions: Pre-operative oxygen uptake kinetics during 6-min walk test predicts short-term clinical outcomes after off-pump coronary artery bypass surgery. From a clinically applicable perspective, a threshold of 66% of pre-operative predicted 6-min walk test distance indicated slower kinetics, which leads to longer intensive care unit and post-surgery hospital length of stay. Implications for rehabilitation: Coronary artery bypass grafting is a treatment aimed to improve expectancy of life and prevent disability due to the disease progression; The use of pre-operative submaximal functional capacity test enabled the identification of patients with high risk of complications, where patients with delayed oxygen uptake kinetics exhibited worse short-term outcomes; Our findings suggest the importance of the rehabilitation in the pre-operative in order to "pre-habilitate" the patients to the surgical procedure; Faster oxygen uptake on-kinetics could be achieved by improving the oxidative capacity of muscles and cardiovascular conditioning through rehabilitation, adding better results following cardiac surgery. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPX) is the gold-standard approach to assessing cardiorespiratory fitness (CRF). The current study puts forth reference standards for peak oxygen (O 2) pulse from the "Fitness Registry and the Importance of Exercise: A National Data Base" (FRIEND) Registry. The current analysis included 13,318 tests from CPX laboratories in the United States, Canada and Europe. Inclusion criteria included CPX data on apparently healthy men and women: 1) aged ≥20 years; 2) with exercise tests performed on a treadmill; and 3) achieving a peak respiratory exchange ratio ≥ 1.00. Peak O 2 pulse 50th percentile values decreased from 20.8 ml/beat in the 2nd decade to 11.2 ml/beat in the 8th decade in men and from 13.6 ml/beat in the 2nd decade to 7.9 ml/beat in the 8th decade in women. Linear regression analysis results produced the following statistically significant (p < 0.001) equation: peak O 2 pulse (ml/beat) = 23.2–0.09(age) - 6.6(sex); female = 1 and male = 0. The assessment of CRF through CPX is an important health metric. Reference standards, such as those put forth in the current study, allow for the comparison of key measures of CRF to expected normal responses across the adult lifespan. • Cardiorespiratory fitness, determined by exercise testing, is considered a vital sign. • Comparing actual exercise testing responses to reference standards for key measures is needed for a comprehensive assessment. • The peak oxygen pulse is determined by dividing peak oxygen consumption by peak heart rate. • Peak oxygen pulse provides insight into cardiac function during exercise. • The current analysis provides reference standards for peak oxygen pulse across the adult lifespan in men and women. [ABSTRACT FROM AUTHOR]

Background: In heart failure (HF), a flattening oxygen consumption (VO2 ) trajectory during cardiopulmonary exercise test (CPET) reflects an acutely compromised cardiac output. We hypothesized that a flattening VO2 trajectory is helpful in phenotyping disease severity and prognosis in HF with either reduced (HFrEF), mid-range (HFmrEF), or preserved (HFpEF) ejection fraction.Methods and Results: Overall, 319 HF patients (198 HFrEF, 80 HFmrEF, and 41 HFpEF) underwent CPET. A flattening VO2 trajectory was tracked and defined as an inflection of VO2 linearity as a function of work rate with a second slope downward inflection >35% extent of the first one. Peak VO2 , the minute ventilation/carbon dioxide production (VE/VCO2 ) slope, and the presence of exercise oscillatory ventilation (EOV) were also determined. Pulmonary artery systolic pressure (PASP) and tricuspid annular plane systolic excursion (TAPSE) were measured by echocardiography. A flattening VO2 occurred in 92 patients (28.8%). PASP and TAPSE at rest were significantly higher and lower (P < 0.001), respectively. The primary outcome was the combination of all-cause death, heart transplantation and left ventricular assist device implantation. The secondary outcome was the primary outcome plus hospitalization for cardiac reasons. In the multivariate model including peak VO2 , VE/VCO2 slope, EOV and VO2 trajectory, a flattening VO2 trajectory and EOV were retained in the regression for primary (X2 = 35.78, and 36.36, respectively; P < 0.001) and secondary (X2 = 12.45 and 47.91, respectively; P < 0.001) outcomes.Conclusions: Results point to a flattening VO2 trajectory as a likely new and strong predictor of events in HF with any ejection fraction. Given the relation of right-sided cardiac dysfunction to pulmonary hypertension, this oxygen pattern might suggest a real-time decrease in pulmonary blood flow to the left heart. [ABSTRACT FROM AUTHOR]

Objective: The objectives of this study were to determine the efficacy of a current physical therapy and weight loss program model on exercise performance, physical function, and cardiometabolic risk factors in obese patients.Design: Retrospective pre-post design.Subjects: A total of 192 patients who previously underwent testing of anthropometric measurements, cardiovascular biomarkers, and lower extremity function scale (LEFS) were included.Results: There was a significant reduction in body weight [5.91 ± 3.47 (95% CI, 5.4 to 6.4) kg; p < 0.001; n = 187] and waist circumference [7.1 ± 5 (95% CI, 6.3 to 7.9) cm; p < 0.001; n = 187]. Submaximal exercise capacity (VO2ex) increased by [5.29 ± 4.74 (95% CI, 4.38 to 6.19) ml/kg/min; p < 0.001; n = 107], and lower extremity functional scale (LEFS) improved by [9 ± 11 (95% CI, 7 to 12) scale points; p < 0.001; n = 75]. Both systolic (pre SBP: 125.7 ± 15 vs. post SBP: 118.4 ± 12 mmHg; p < 0.001; n = 150) and diastolic (pre DBP: 78.5 ± 10 vs. post DBP: 74 ± 8.5 mmHg; p < 0.001; n = 150) blood pressures as well as fasting blood glucose (pre FBG: 112.8 ± 37 vs. post FBG: 99 ± 18 mg/dL; p < 0.001; n = 132) were significantly reduced.Conclusions: This study indicates the importance and significance of weight loss in improving physical function and cardiometabolic risk profiles across a cohort of outpatient physical therapy patients. Our study also suggests that weight loss can be achieved in a comprehensive exercise intensive physical therapy program for obese patients. [ABSTRACT FROM PUBLISHER]

Objective: To evaluate the impact of a short-term neuromuscular electrical stimulation program on exercise tolerance in hospitalized patients with advanced heart failure who have suffered an acute decompensation and are under continuous intravenous inotropic support. Design: A randomized controlled study. Subjects: Initially, 195 patients hospitalized for decompensated heart failure were recruited, but 70 were randomized. Intervention: Patients were randomized into two groups: control group subject to the usual care (n = 35); neuromuscular electrical stimulation group (n = 35) received daily training sessions to both lower extremities for around two weeks. Main measures: The baseline 6-minute walk test to determine functional capacity was performed 24 hours after hospital admission, and intravenous inotropic support dose was daily checked in all patients. The outcomes were measured in two weeks or at the discharge if the patients were sent back home earlier than two weeks. Results: After losses of follow-up, a total of 49 patients were included and considered for final analysis (control group, n = 25 and neuromuscular electrical stimulation group, n = 24). The neuromuscular electrical stimulation group presented with a higher 6-minute walk test distance compared to the control group after the study protocol (293 ± 34.78 m vs. 265.8 ± 48.53 m, P < 0.001, respectively). Neuromuscular electrical stimulation group also demonstrated a significantly higher dose reduction of dobutamine compared to control group after the study protocol (2.72 ± 1.72 µg/kg/min vs. 3.86 ± 1.61 µg/kg/min, P = 0.001, respectively). Conclusion: A short-term inpatient neuromuscular electrical stimulation rehabilitation protocol improved exercise tolerance and reduced intravenous inotropic support necessity in patients with advanced heart failure suffering a decompensation episode. [ABSTRACT FROM AUTHOR]

Objectives:Despite considerable knowledge regarding the importance of stress in coronary artery disease (CAD) pathogenesis, its underestimation persists in routine clinical practice, in part attributable to lack of a standardized, objective assessment. The current study examined the ability of stress hormones to predict CAD severity and prognosis at basal conditions as well as during and following an exertional stimulus. Materials and methods:Forty Caucasian subjects with significant coronary artery lesions (≥50%) were included. Within 2 months of coronary angiography, cardiopulmonary exercise testing (CPET) on a recumbent ergometer was performed in conjunction with stress echocardiography (SE). At rest, peak and after 3 min of recovery following CPET, plasma levels of cortisol, adrenocorticotropic hormone (ACTH) and NT-pro-brain natriuretic peptide (NT-pro-BNP) were measured by immunoassay sandwich technique, radioimmunoassay, and radioimmunometric technique, respectively. Subjects were subsequently followed a mean of 32 ± 10 months. Results and discussion:Mean ejection fraction was 56.7 ± 9.6%. Subjects with 1–2 stenotic coronary arteries (SCA) demonstrated a significantly lower plasma cortisol levels during CPET compared to those with 3-SCA (p < .05), whereas ACTH and NT-pro-BNP were not significantly different (p > .05). Among CPET, SE, and hormonal parameters, cortisol at rest and during CPET recovery demonstrated the best predictive value in distinguishing between 1-, 2-, and 3-SCA [area under ROC curve 0.75 and 0.77 (SE = 0.11, 0.10;p = .043, .04) for rest and recovery, respectively]. ΔCortisol peak/rest predicted cumulative cardiac events (area under ROC curve 0.75, SE = 0.10,p = .049). Conclusions:Cortisol at rest and following an exercise test holds predictive value for CAD severity and prognosis, further demonstrating a link between stress and unwanted cardiac events. [ABSTRACT FROM AUTHOR]

Purpose:To investigate if cardiovascular and metabolic responses to the six-minute walk test (6MWT) and incremental shuttle walking test (ISWT) are in agreement with cardiopulmonary exercise testing (CPX) and determine if both submaximal tests are interchangeable in obese and eutrophic individuals. Method:Observational and cross-sectional study included 51 obese women (ObG) and 21 controls (CG) (20–45 years old). Subjects underwent clinical evaluation, CPX, the 6MWT and ISWT. We applied Bland–Altman plots to assess agreement between walking tests and CPX. Correlation analysis assessed relationships between key variables. Results:There was an agreement between CPX and both the 6MWT [oxygen uptake (VO2mL kg−1 min−1) = 6.9 (CI: 5.7–8.1), and heart rate (bpm) = 37.0 (CI: 33.3–40.7)] and ISWT [VO2(mL kg−1 min−1) = 6.1 (CI: 4.9–7.3), and heart rate (bpm) = 36.2 (CI: 32.1–40.3)]. We found similar cardiovascular and metabolic responses to both tests in the ObG but not in the CG. Strong correlations were demonstrated between 6MWT and ISWT variables: VO2(r = 0.70); dyspnoea (r = 0.80); and leg fatigue (r = 0.70). Conclusions:6MWT and ISWT may both hold interchangeable clinical value when contrasted with CPX in obese women and may be a viable alternative in the clinical setting when resources and staffing are limited.Implications for RehabilitationObesity is a worldwide epidemic, with high prevalence in women, and it is associated to impaired cardiorespiratory fitness and functional capacity as well as high mortality risk.Assessing oxygen uptake by means of cardiopulmonary exercise testing is the gold standard method for evaluating and stratifying cardiorespiratory fitness, however it is not ever applied due to costs and staffing.Walking field tests may be a cost-effective approach that provides valuable information regarding the functional capacity in agreement to metabolic and cardiovascular responses of cardiopulmonary exercise testing. [ABSTRACT FROM AUTHOR]

The objective of the present study is to evaluate the acute effects of low-level laser therapy (LLLT) on functional capacity, perceived exertion, and blood lactate in hospitalized patients with heart failure (HF). Patients diagnosed with systolic HF (left ventricular ejection fraction <45 %) were randomized and allocated prospectively into two groups: placebo LLLT group (n = 10)-subjects who were submitted to placebo laser and active LLLT group (n = 10)-subjects who were submitted to active laser. The 6-min walk test (6MWT) was performed, and blood lactate was determined at rest (before LLLT application and 6MWT), immediately after the exercise test (time 0) and recovery (3, 6, and 30 min). A multi-diode LLLT cluster probe (DMC, São Carlos, Brazil) was used. Both groups increased 6MWT distance after active or placebo LLLT application compared to baseline values (p = 0.03 and p = 0.01, respectively); however, no difference was observed during intergroup comparison. The active LLLT group showed a significant reduction in the perceived exertion Borg (PEB) scale compared to the placebo LLLT group (p = 0.006). In addition, the group that received active LLLT showed no statistically significant difference for the blood lactate level through the times analyzed. The placebo LLLT group demonstrated a significant increase in blood lactate between the rest and recovery phase (p < 0.05). Acute effects of LLLT irradiation on skeletal musculature were not able to improve the functional capacity of hospitalized patients with HF, although it may favorably modulate blood lactate metabolism and reduce perceived muscle fatigue. [ABSTRACT FROM AUTHOR]

Background Non-invasive assessment of haemodynamic function by impedance cardiography ( IC) constitutes an interesting approach to monitor cardiac function in patients with coronary artery disease ( CAD). However, such measurements are most often performed at rest, whereas symptoms are also possible during exertion, particularly at higher intensities. In addition, the association between IC during exertion and cardiopulmonary exercise testing ( CPX) is not well understood in these patients, which was the aim of this study. Methods Nineteen men (age = 62 ± 6 years) with CAD [left ventricular ejection fraction ( LVEF) = 61 ± 10%] underwent a CPX using an incremental protocol on a cycle ergometer, with simultaneous measurement of IC. Cardiac output ( CO), stroke volume ( SV), cardiac index ( CI), peak oxygen consumption ( VO2), the oxygen uptake efficiency slope ( OUES), circulatory power and ventilatory power were determined. Results Pearson product-moment correlation analysis revealed peak VO2 ( r = 0·46) was significantly related to CO. Peak oxygen pulse (0·52) was associated with SV. OUES was associated with resting SV (0·47) and with peak SV ( r = 0·52). Conclusion These findings suggest that IC indices are associated with certain, but not all, established CPX measures in patients with stable CAD. [ABSTRACT FROM AUTHOR]

The article discusses a research study conducted to prove that the combined functional capacity of cardiopulmonary exercise testing (CPET) and right ventricular (RV)-pulmonary circulation coupling can improve the classification and risk prediction relating to heart failure (HF). Topics covered include the relationship of tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP), exercise oscillatory ventilation (EOV) in HF, and the study's limitations.

Abstract: Background: Previous research has demonstrated the prognostic value of cardiopulmonary exercise testing (CPX) in elderly patients with heart failure (HF). Investigations that have comprehensively examined the value of CPX across different age groups are lacking. The purpose of the present investigation was to evaluate the prognostic value of CPX in young, middle-aged and older patients with HF. Methods: A total of 1605 subjects (age: 59.2±13.7years, 78% male) underwent CPX and were subsequently tracked for major cardiac events. Ventilatory efficiency (VE/VCO2 slope) and peak oxygen consumption (VO2), both absolute and percent-predicted, were determined. The prognostic value of these CPX variables was assessed in ≤45, 46–65 and ≥66year subgroups. Results: The three year event rates for major cardiac events in the ≤45, 46–65 and ≥66year subgroups were 8.8%, 6.0% and 5.7%, respectively. The VE/VCO2 slope (Hazard ratio≥1.07, p<0.001), peak VO2 (Hazard ratio≤0.87, p<0.001) and percent-predicted peak VO2 (Hazard ratio≤0.98, p<0.001) were all significant prognostic markers in each age subgroup. While the VE/VCO2 slope carried the greatest prognostic strength, peak VO2 and percent-predicted peak VO2 were retained in multivariate analyses (Residual Chi-Square≥5.2, p<0.05). With respect to peak VO2, the actual value was the more robust prognostic marker in the ≤45 and ≥66year subgroups while the percent-predicted expression provided better predictive resolution in subjects who were 46–65years old. Conclusions: These results indicate that, irrespective of a patient''s age at presentation, CPX provides valuable prognostic information in the HF population. [Copyright &y& Elsevier]

The article presents a study that determined if ventilatory efficiency and peak oxygen consumption, which provide information on heart patients undergoing cardiopulmonary exercise testing (CPX), can be used for long term prognosis. The study revealed that values taken from the ventilatory efficiency slope is an excellent predictor of adverse effects during a CPX patient's period of follow-ups and that peak oxygen consumption value provides additive prognosis within the first two years of follow-up.

Background: There is an increasing recognition of the potential value of cardiopulmonary exercise testing (CPX) in patients with pulmonary hypertension (PH). Key CPX characteristics in these patients include: (1) a diminished aerobic capacity; (2) an abnormally elevated minute ventilation–carbon dioxide production relationship; and (3) an abnormally diminished partial pressure of end-tidal carbon dioxide. Given the burgeoning number of original research investigations utilizing CPX in patients with PH, a summation of the presently available body of literature seems timely. Methods: A literature search was conducted in pubmed using “cardiopulmonary exercise testing” and “pulmonary arterial hypertension” as key phrases. Only studies conducting exercise testing with simultaneous ventilatory expired gas analysis in subjects with a confirmed diagnosis of pulmonary arterial hypertension were included. Twenty-three investigations were included in this review. Nineteen of the investigations assessed cohorts with resting pulmonary arterial hypertension as the sole diagnosis. Two investigations assessed subjects with chronic obstructive pulmonary disease and pulmonary arterial hypertension: one assessed subjects with pulmonary fibrosis and pulmonary arterial hypertension, and another included groups with exercise-induced pulmonary arterial hypertension and resting pulmonary arterial hypertension. Results: Collectively, these investigations indicate variables obtained from CPX: (1) reflect varying degrees of PH severity; (2) positively respond to several pharmacologic and surgical interventions; and (3) may provide prognostic value. Conclusions: Currently, CPX is not widely utilized in patients with PH. Although more research is required in a number of areas, the present evidence-based review indicates this exercise testing technique may provide valuable information in the PH population. [Copyright &y& Elsevier]

The article discusses the study which involves the six-minute walk test (6MTW) and cardiopulmonary exercise testing (CPET) to assess the functional limitations of patients with heart failure (HF) at the Sao Paolo Hospital in Brazil. It notes that the study compared the clinical and prognostic validity of the two techniques to determine the health status of the patients with HP. It concludes that 6MWT confirms to be simple and reliable but no evidence of usage as a prognostic marker.

This study tested the hypothesis that increasing levels of maximal dyspnea on exertion (DOE) during cardiopulmonary exercise testing (CPX) is associated with heart failure (HF) disease severity and worsening prognosis. Three hundred seventy-six HF patients underwent CPX where ventilatory efficiency (minute ventilation/carbon dioxide production; VE/VCO2 slope), peak oxygen consumption (VO2), and maximal DOE were determined. A subgroup of 243 patients underwent echocardiography with tissue Doppler imaging to measure the ratio between mitral early (E) to mitral annular (E′) velocity as well as other variables. Maximal DOE was significantly correlated with E/E′ (rs=.49; P<.001). In the multivariate Cox regression, the VE/VCO2 slope was the strongest prognostic marker obtained from CPX (Multivariate chi-square, 48.0; P<.001) while maximal DOE (residual chi-square, 17.4; P<.001) and peak VO2 (residual chi-square, 7.5; P=.006) added predictive value. These results suggest that increasing DOE reflects the degree of disease severity and adds prognostic value to established CPX variables. [ABSTRACT FROM AUTHOR]

Several investigations have demonstrated that higher body weight, as assessed by the body mass index, is associated with improved prognosis in patients with heart failure (HF). The purpose of the present investigation was to assess the influence of HF etiology on the prognostic ability of the body mass index in a cohort undergoing cardiopulmonary exercise testing. A total of 1,160 subjects were included in the analysis. All subjects underwent cardiopulmonary exercise testing, at which the minute ventilation/carbon dioxide production slope and peak oxygen consumption were determined. In the overall group, 193 cardiac deaths occurred during a mean follow-up of 30.7 ± 25.6 months (annual event rate 6.0%). The subjects classified as obese consistently had improved survival compared to those classified as normal weight (overall survival rate 88.0% vs ≤81.1%, p <0.001). Differences in survival according to HF etiology were observed for those classified as overweight. In the ischemic subgroup, the survival characteristics for the overweight subjects (75.5%) were similar those for subjects classified as normal weight (81.1%). The converse was true for the nonischemic subgroup, for whom the survival trends for the obese (86.4%) and overweight subjects (88.4%) were similar. The minute ventilation/carbon dioxide production slope was the strongest prognostic marker (chi-square ≥43.4, p <0.001) for both etiologies, and the body mass index added prognostic value (residual chi-square ≥4.7, p <0.05). In conclusion, these results further support the notion that obesity confers improved prognosis in patients with HF, irrespective of the HF etiology. Moreover, the body mass index appears to add predictive value during the cardiopulmonary exercise testing assessment. However, survival appears to differ according to HF etiology in subjects classified as overweight. [Copyright &y& Elsevier]

Cardiopulmonary exercise testing (CPET) is a well-accepted physiologic evaluation technique in patients diagnosed with heart failure and in patients presenting with unexplained dyspnea on exertion. Several variables obtained during CPET, including oxygen consumption relative to heart rate and work rate provide consistent, quantitative patterns of abnormal physiologic responses to graded exercise when left ventricular dysfunction is caused by myocardial ischemia. This concept report describes both the methodology and clinical application of CPET associated with myocardial ischemia. Initial evidence indicates left ventricular dysfunction induced by myocardial ischemia may be accurately detected by an abnormal CPET response. CPET testing may complement current noninvasive testing modalities that elicit inducible ischemia. It provides a physiologic quantification of the work rate, heart rate, and O2 uptake at which myocardial ischemia develops. In conclusion, adding CPET with gas exchange measurements is likely to be of value in diagnosing and quantifying both overt and occult myocardial ischemia and its reversibility with treatment. [Copyright &y& Elsevier]

Objective: The aim of this study is to evaluate the predictive accuracy of a cardiopulmonary exercise test (CPX) score. Background: Cardiopulmonary exercise test responses, including peak VO2, markers of ventilatory inefficiency (eg, the VE/VCO2 slope and oxygen uptake efficiency slope [OUES]), and hemodynamic responses, such as heart rate recovery (HRR) and chronotropic incompetence (CRI) are strong predictors of outcomes in patients with heart failure (HF). However, there is a need for simplified approaches that integrate the additive prognostic information from CPX. Methods: At 4 institutions, 710 patients with HF (568 male/142 female, mean age 56 ± 13 years, resting left ventricular ejection fraction 33 ± 14%) underwent CPX and were followed for cardiac-related mortality and separately for major cardiac events (death, hospitalization for HF, transplantation, left ventricular assist device implantation) for a mean of 29 ± 25 months. The age-adjusted prognostic power of peak VO2, VE/VCO2 slope, OUES (VO2 = a log10VE + b), resting end-tidal carbon dioxide pressure (PetCO2), HRR, and CRI were determined using Cox proportional hazards analysis, optimal cutpoints were determined, the variables were weighted, and a multivariate score was derived. Results: There were 175 composite outcomes. The VE/VCO2 slope (≥34) was the strongest predictor of risk and was attributed a relative weight of 7, with weighted scores for abnormal HRR (≤6 beats at 1 minute), OUES (>1.4), PetCO2 (<33 mm Hg), and peak VO2 (≤14 mL kg−1 min−1) having scores of 5, 3, 3, and 2, respectively. Chronotropic incompetence was not a significant predictor and was excluded from the score. A summed score >15 was associated with an annual mortality rate of 27% and a relative risk of 7.6, whereas a score <5 was associated with a mortality rate of 0.4%. The composite score was the most accurate predictor of cardiovascular events among all CPX responses considered (concordance indexes 0.77 for mortality and 0.75 for composite outcome composed of mortality, transplantation, left ventricular assist device implantation, and HF-related hospitalization). The summed score remained significantly associated with increased risk after adjusting for age, gender, body mass index, ejection fraction, and cardiomyopathy type. Conclusion: A multivariable score based on readily available CPX responses provides a simple and integrated method that powerfully predicts outcomes in patients with HF. [Copyright &y& Elsevier]

Cardiopulmonary exercise testing (CPX) is an integral tool for assessing the clinical status and prognosis of patients with heart failure (HF). The present investigation examined differences in CPX variables and prognosis according to reason for test termination. One hundred eighty-three patients with HF (69% men, 31% women; mean age 53 ± 13 years, left ventricular ejection fraction at rest 24.3 ± 9.9%) underwent CPX in which the minute ventilation/carbon dioxide production slope, peak oxygen consumption, and peak respiratory exchange ratio were determined. Subjects were tracked for cardiac-related events for 2 years after CPX. Dyspnea and fatigue (general fatigue/leg fatigue) were the primary reasons for test termination in 79 and 104 patients, respectively. Peak oxygen consumption (15.4 ± 5.7 vs 17.5 ± 5.9 ml o 2 · kg−1 · min−1) was significantly lower, whereas minute ventilation/carbon dioxide production slope (38.5 ± 12.8 vs 33.9 ± 9.8) was significantly higher in the dyspnea subgroup (p <0.05). There were 41 cardiac-related events during the 2-year tracking period. Patients with dyspnea were at significantly higher risk of adverse events (hazard ratio 2.1, 95% confidence interval 1.1 to 4.0, p = 0.02). In conclusion, these results indicate that patients with HF terminating an exercise test primarily because of dyspnea have an increased incidence of cardiac-related events and poorer CPX markers than those limited by fatigue. [Copyright &y& Elsevier]

Abstract: Background: Cardiopulmonary exercise testing (CPET) variables provide valuable prognostic information in the heart failure (HF) population. The purpose of the present study is to assess the ability of resting end-tidal carbon dioxide partial pressure (PETCO2) to predict cardiac-related events in patients with HF. Methods: 121 subjects diagnosed with compensated HF underwent CPET on an outpatient basis. Mean age and ejection fraction were 49.3 years (±14.7) and 28.4% (±13.4), respectively. Resting PETCO2 was determined immediately prior to the exercise test in the seated position. Peak oxygen consumption (VO2) and the minute ventilation-carbon dioxide production (VE/VCO2) slope were also acquired during CPET. Results: There were 41 cardiac-related hospitalizations and 9 cardiac-related deaths in the year following CPET. Mean resting PETCO2, peak VO2 and VE/VCO2 slope were 34.1 mmHg (±4.6), 14.5 ml•kg−1•min−1 (±5.1) and 35.9 (±8.7) respectively. Univariate Cox regression analysis revealed that resting PETCO2 (Chi-square=28.4, p <0.001), peak VO2 (Chi-square=21.6, p <0.001) and VE/VCO2 slope (Chi-square=54.9, p <0.001) were all significant predictors of cardiac related events. Multivariate Cox regression analysis revealed resting PETCO2 added to the prognostic value of VE/VCO2 slope in predicting cardiac related events (residual Chi-square=4.4, p =0.04). Peak VO2 did not add additional value and was removed (residual Chi-square=3.2, p =0.08). Conclusions: These results indicate a resting ventilatory expired gas variable possesses prognostic value independently and in combination with an established prognostic marker from the CPET. Resting PETCO2 may therefore be a valuable objective measure to obtain during both non-exercise and exercise evaluations in patients with HF. [Copyright &y& Elsevier]

Purpose: Normative standards for key cardiopulmonary exercise (CPX) test variables, including peak circulatory power (CircP), are needed to guide the interpretation of clinical exercise responses in individuals with and without disease. Objective: This study aimed to establish age- and sex-specific reference standards for peak CircP derived from a healthy cohort from the Fitness Registry and the Importance of Exercise: A National Database (FRIEND). Methods: CPX test data from apparently healthy males and females from eight FRIEND United States exercise laboratories were considered. Inclusion criteria included ages 20–79 yr and a maximal, symptom-limited exercise test performed on a treadmill or cycle ergometer. CircP was calculated as the product of peak oxygen consumption and peak systolic blood pressure. Reference values were determined on both treadmill and cycle ergometer for males and females per age decade. A stepwise linear regression to predict CircP was derived from two-thirds of the sample while the remaining one-third was used as a validation cohort. Results: A total of 6736 CPX tests (47% treadmill, 53% female) were included in the analysis. Overall, CircP was higher in males, higher on tests conducted on a treadmill, and decreased with age. Sex, exercise mode, age, and body mass index were the most significant contributors to CircP (multiple R = 0.75, R 2 = 0.57, root-mean-square error = 1200 mm Hg·mL O2·kg−1·min−1, P < 0.001). Using the generated prediction equation, the average percent-predicted CircP for the validation cohort was 101.3% ± 28.1%. Conclusions: These results establish reference standards for CircP, a potentially important prognostic indicator of cardiovascular health. Future research exploring the role of percentiles and percent-predicted values for CircP is necessary as they may provide additional prognostic insight. [ABSTRACT FROM AUTHOR]

Abstract: We hypothesized that heart rate recovery (HRR) will provide superior prognostic resolution in female compared to male heart failure (HF) patients. A total of 745 patients with HF underwent exercise testing to determine HRR. While receiver operating characteristic curve analysis revealed HRR prognostic classification schemes were significant for both males (area: 0.72, 95% CI: 0.67–0.78, p <0.001) and females (area: 0.82, 95% CI: 0.75–0.89, p <0.001), it was stronger in the latter group. The prognostic strength of HRR may be superior in female HF patients. This discrepancy may be driven by the ability of HRR to better reflect autonomic function in females. [ABSTRACT FROM AUTHOR]

Abstract: The oxygen uptake efficiency slope (OUES) response has not been characterized in heart failure (HF) patients with a normal ejection fraction (NEF). Fifty-nine subjects with systolic HF, 59 with HF-NEF and 28 healthy age-matched controls participated in this analysis. The OUES (systolic HF: 1.23±0.41 vs. HF-NEF: 1.22±0.30 vs. controls: 1.51±0.49) was significantly reduced in both HF groups compared to controls (p <0.001). Compared to healthy controls, the OUES is reduced in HF-NEF patients to a similar degree as those with systolic HF. Thus, as in systolic HF, the OUES may provide clinically useful information in patients with HF-NEF. [ABSTRACT FROM AUTHOR]

Objective: The aim of this work was to evaluate the hemodynamic, autonomic, and metabolic responses during resistance and dynamic exercise before and after an 8-week resistance training program using a low-intensity (30% of 1 repetitium maximum), high-repetition (3 sets of 20 repetitions) model, added to an aerobic training program, in a coronary artery disease cohort. Design: Twenty male subjects with coronary artery disease (61.1 ± 4.7 years) were randomly assigned to a combined training group (resistance + aerobic) or aerobic training group (AG). Heart rate, stroke volume, cardiac output, minute ventilation, blood lactate, and parasympathetic modulation indices of heart rate (square root of the mean squared differences of successive RR intervals [RMSSD] and dispersion of points perpendicular to the line of identity that provides information about the instantaneous beat-to-beat variability [SD1]) were obtained before and after an 8-week RT program while performing exercise on a cycle ergometer and a 45-degree leg press. Results: Resistance training resulted in an increase in maximal and submaximal load tolerance (P < 0.01), a decreased hemodynamic response (P < 0.01), and a reduction in blood lactate in the combined training group compared to the aerobic training group during the 45-degree leg press. During exercise on a cycle ergometer, there was a decreased hemodynamic response and increased minute ventilation (P < 0.01). The 8-week RT program resulted in greater parasympathetic tone (RMSSD and SD1 ) and an increase in the SDNN index during exercise on a cycle ergometer and 45-degree leg press (P < 0.05). Conclusions: An 8-week resistance training program associated with aerobic training may attenuate hemodynamic stress, and modify metabolic and autonomic responses during resistance exercise. The training program also appeared to elicit beneficial cardiovascular and autonomic effects during exercise. [ABSTRACT FROM AUTHOR]

In this article, the author discusses the study on the use of cardiopulmonary exercise (CPX) tests in the diagnosis of pulmonary arterial hypertension (PAH). The study shows that patients with resting PAH had an abnormal minute ventilation/carbon dioxide production (VE/VCO2) and partial pressure of end-tidal carbon dioxide production (PETCO2). The author says that the study has a small sample size and additional studies are still needed on the subject.

The left ventricular assist device (LVAD) is an accepted treatment alternative for the management of end-stage heart failure. As we move toward implantation of LVADs in less severe cases of HF, scrutiny of functional capacity and quality of life becomes more important. Patients demonstrate improvements in exercise capacity after LVAD implantation, but the effect is less than predicted. Exercise training produces multiple beneficial effects in heart failure patients, which would be expected to improve quality of life. In this review, we describe factors that are thought to participate in the persistent exercise impairment in LVAD-supported patients, summarize current knowledge about the effect of exercise training in LVAD-supported patients, and suggest areas for future research. [ABSTRACT FROM AUTHOR]

Purpose: Diabetes increases mortality after myocardial infarction, but participation in cardiac rehabilitation (CR) reduces this risk. Our objectives were to examine whether attendance at CR and changes in cardiorespiratory fitness differed according to diabetic status and sex. Methods: Retrospective cohort study of patients referred for CR in Calgary between 1996 and 2010. Cardiorespiratory fitness in metabolic equivalents (METs) was estimated by maximal exercise testing at baseline, at the end of the 12-wk CR program, and 1-yr after CR. Results: Among 7036 nondiabetic and 1546 diabetic patients who started, 84.9% of nondiabetic versus 79.5% of diabetic patients completed CR (P < 0.0001). The difference between diabetic and nondiabetic patients was greater in women (81.7% vs 72.1%, P < 0.0001) than that in men (86.0% vs 82.5%, P = 0.004). Patients without diabetes were more likely to return for the 1-yr assessment (53.7% vs 42.7%, P < 0.0001), and nondiabetic women were more likely than diabetic women to attend the 1-yr follow-up (44.3% vs 31.7%, P < 0.0001). Change in cardiorespiratory fitness from baseline to 12 wk was +1.0 METs in nondiabetic men, +0.9 METS in diabetic men, +0.9 METs in nondiabetic women, and +0.7 METs in diabetic women (within-group change; P = 0.0009). Changes in cardiorespiratory fitness at 1 yr compared with baseline were +0.9, +0.6, +0.9, and +0.5 METS, respectively (within- group change, P = 0.0001). Conclusions: Patients with diabetes, especially females, were less likely than patients without diabetes to complete CR and attend follow-up. Among patients who attended 1-yr follow-up, changes in cardiorespiratory fitness were not as well maintained in diabetic patients as in nondiabetic patients. Identifying barriers and targeting CR adherence interventions to patients with diabetes may help improve outcomes. [ABSTRACT FROM AUTHOR]

Background: Aging leads to low functional capacity and this can be reversed by safe and adequate exercise prescription. Objective: The aim of this study was to identify the anaerobic threshold (AT) obtained from the V-slope method as well as visual inspection of oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) curves and compare findings with the heteroscedastic (HS) method applied to carbon dioxide production (̇vO2), heart rate (HR), and HHb data in healthy elderly men. A secondary aim was to assess the degree of agreement between methods for AT determination. Method: Fourteen healthy men (61.4±6.3 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer until physical exhaustion. Biological signals collected during CPX included: ventilatory and metabolic variables; spectroscopy quasi-infrared rays -- NIRS; and HR through a cardio-frequency meter. Results: We observed temporal equivalence and similar values of power (W), absolute oxygen consumption (̇vO2- mL/min), relative ̇vO2 (mL.Kg-1.min-1), and HR at AT by the detection methods performed. In addition, by the Bland-Altman plot, HR confirmed good agreement between the methods with biases between -- 1.3 and 3.5 beats per minute. Conclusions: (i) all detection methods were sensitive in identifying AT, including the HS applied to HR and (ii) the methods showed a good correlation in the identification of AT. Thus, these results support HR as valid and readily available parameter in determining AT in healthy elderly men. [ABSTRACT FROM AUTHOR]

Cardiorespiratory fitness (CRF) is now considered a vital sign. Cardiopulmonary exercise testing (CPET) is the gold-standard assessment of CRF; peak oxygen consumption (VO 2) and the minute ventilation/carbon dioxide production (VE/VCO 2) slope are considered primary CPET measures of CRF. More work is needed to determine the role of this exercise assessment in the primary care setting. 695 subjects (mean age: 62 ± 13 years, body mass index: 28.9 ± 5.3 kg/m2, 375 female and 320 male) underwent CPET using a cycle ergometer. 95% of the cohort had one or more major cardiovascular risk factor (i.e., obesity, smoking, dyslipidemia, hypertension, diabetes); no subject was diagnosed with cardiovascular disease (CVD) at the time of CPET. Subjects were tracked for the composite endpoint of cardiovascular mortality or hospital admission. Mean peak VO 2 , VE/VCO 2 slope and peak respiratory exchange ratio were 17.8 ± 5.8 mlO 2 •kg−1•min−1, 26.7 ± 4.1, and 1.18 ± 0.13, respectively. There were 42 composite events during the 64 ± 18 month tracking period. Both peak VO 2 (Chi-square 16.3, p < 0.001) and the VE/VCO 2 slope (Chi-square 14.9, p < 0.001) were significant univariate predictors of the composite endpoint. The VE/VCO 2 slope added significant predictive value to peak VO 2 and was retained in the multivariate regression (residual Chi-square 7.0, p = 0.008). These results support the prognostic value of CPET prior to a CVD diagnosis. The prognostic value of the VE/VCO 2 slope, not commonly the focus of CPET trials in patients with one or more major cardiovascular risk factors but without a confirmed CVD diagnosis, is a particularly novel finding in the current study. • Cardiopulmonary exercise testing is the gold-standard assessment of cardiorespiratory fitness. • While the prognostic value of CPET is clear in cardiopulmonary patients, more work is needed to determine its value in the primary care setting. • These results support the prognostic value of peak oxygen consumption and the VE/VCO2 slope prior to a CVD diagnosis. • The prognostic value of the VE/VCO2 slope in patients without a confirmed CVD diagnosis is a particularly novel finding in the current study. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Equations are often used to predict cardiorespiratory fitness (CRF) from submaximal or maximal exercise tests. However, no study has comprehensively compared these exercise-based equations with directly measured CRF using data from a single, large cohort. Purpose: This study aimed to compare the accuracy of exercise-based prediction equations with directly measured CRF and evaluate their ability to classify an individual's CRF. Methods: The sample included 4871 tests from apparently healthy adults (38% female, age 44.4 ± 12.3 yr (mean ± SD)). Estimated CRF (eCRF) was determined from 2 nonexercise equations, 3 submaximal exercise equations, and 10 maximal exercise equations; all eCRF calculations were then compared with directly measured CRF, determined from a cardiopulmonary exercise test. Analysis included Pearson product–moment correlations, standard error of estimate values, intraclass correlation coefficients, Cohen κ coefficients, and the Benjamini–Hochberg procedure to compare eCRF with directly measured CRF. Results: All eCRF values from the prediction equations were associated with directly measured CRF (P < 0.01), with intraclass correlation coefficient estimates ranging from 0.07 to 0.89. Although significant agreement was found when using eCRF to categorize participants into fitness tertiles, submaximal exercise equations correctly classified an average of only 51% (range, 37%–58%) and maximal exercise equations correctly classified an average of only 59% (range, 43%–76%). Conclusions: Despite significant associations between exercise-based prediction equations and directly measured CRF, the equations had a low degree of accuracy in categorizing participants into fitness tertiles, a key requirement when stratifying risk within a clinical setting. The present analysis highlights the limited accuracy of exercise-based determinations of eCRF and suggests the need to include cardiopulmonary measures with maximal exercise to accurately assess CRF within a clinical setting. [ABSTRACT FROM AUTHOR]

Purpose: Cardiopulmonary exercise testing (CPX) provides valuable clinical information, including peak ventilation (V ˙Epeak), which has been shown to have diagnostic and prognostic value in the assessment of patients with underlying pulmonary disease. This report provides reference standards for V ˙Epeak derived from CPX on treadmills in apparently healthy individuals. Methods: Nine laboratories in the United States experienced in CPX administration with established quality control procedures contributed to the Fitness Registry and the Importance of Exercise National Database from 2014 to 2017. Data from 5232 maximal exercise tests from men and women without cardiovascular or pulmonary disease were used to create percentiles of V ˙Epeak for both men and women by decade between 20 and 79 yr. Additionally, prediction equations were developed for V ˙Epeak using descriptive information. R esults : V ˙Epeak was found to be significantly different between men and women and across age groups (P < 0.05). The rate of decline in V ˙Epeak was 8.0% per decade for both men and women. A stepwise regression model of 70% of the sample revealed that sex, age, and height were significant predictors of V ˙Epeak. The equation was cross-validated with data from the remaining 30% of the sample with a final equation developed from the full sample (r = 0.73). Additionally, a linear regression model revealed forced expiratory volume in 1 s significantly predicted V ˙Epeak (r = 0.73). Conclusions: Reference standards were developed for V ˙Epeak for the United States population. Cardiopulmonary exercise testing laboratories will be able to provide interpretation of V ˙Epeak from these age and sex-specific percentile reference values or alternatively can use these nonexercise prediction equations incorporating sex, age, and height or with a single predictor of forced expiratory volume in 1 s. [ABSTRACT FROM AUTHOR]

Introduction Percent of predicted peak VO 2 (ppVO 2 ) is considered a standard measure for establishing disease severity, however, there are known limitations to traditional normative values. This study sought to compare ppVO 2 from the newly derived “ F itness R egistry and the I mportance of E xercise: a N ational D atabase” (FRIEND) registry equation to conventional prediction equations in a clinical cohort of patients undergoing cardiopulmonary exercise testing (CPX). Methods and results We selected 1094 patients referred for evaluation of heart failure (HF) symptoms who underwent CPX. ppVO 2 was calculated using the FRIEND, Wasserman/Hansen and Jones equations. Participants were followed for a median of 4.5 years [Interquartile range 3.5–6.0] for the composite endpoint of death, advanced HF therapy, or acute decompensated HF requiring hospital admission. Mean age was 48 ± 15 years and 62% were female. The FRIEND registry equation predicted the lowest ppVO 2 (measured/predicted; 71 ± 31%), compared to the Wasserman/Hansen (74 ± 29%) and Jones equations (83 ± 33%) ( p  < 0.001). All expressions of peak VO 2 were significant as univariate predictors of outcome with no significant differences between equations on pairwise analysis of receiver operating characteristic curves. When compared at a similar threshold of ppVO 2 the event rate was significantly lower in the FRIEND registry equation versus the currently used Wasserman and Jones equations. Conclusion The use of the newly derived FRIEND registry equation predicts HF outcomes; however, it appears to predict a higher predicted VO 2 ; the clinical implication being a lower threshold of percent predicted peak VO 2 should be considered when risk stratifying patients with HF. [ABSTRACT FROM AUTHOR]

Compared with traditional exercise tests, cardiopulmonary exercise testing (CPET) provides a thorough assessment of exercise integrative physiology involving the pulmonary, cardiovascular, muscular, and cellular oxidative systems. Due to the prognostic ability of key variables, CPET applications in cardiology have grown impressively to include all forms of exercise intolerance, with a predominant focus on heart failure with reduced or with preserved ejection fraction. As impaired cardiac output and peripheral oxygen diffusion are the main determinants of the abnormal functional response in cardiac patients, invasive CPET has gained new popularity, especially for diagnosing early heart failure with preserved ejection fraction and exercise-induced pulmonary hypertension. The most impactful advance has recently come from the introduction of CPET combined with echocardiography or CPET imaging, which provides basic information regarding cardiac and valve morphology and function. This review highlights modern CPET use as a single or combined test that allows the pathophysiological bases of exercise limitation to be translated, quite easily, into clinical practice. [ABSTRACT FROM AUTHOR]