Predictor Of Peak Oxygen Uptake Research Articles

Echocardiographic assessment for cardiopulmonary function in patients with congenital heart disease-related pulmonary arterial hypertension

BackgroundFor patients with congenital heart disease-related pulmonary arterial hypertension (CHD-PAH), cardiopulmonary exercise testing (CPET) can reflect cardiopulmonary reserve function. However, CPET may not be readily accessible for patients with high-risk conditions or limited mobility due to disability. Echocardiography, on the other hand, serves as a widely available diagnostic tool for all CHD-PAH patients. This study was aimed to identify the parameters of echocardiography that could serve as indicators of cardiopulmonary function and exercise capacity.MethodsA cohort of 70 patients contributed a total of 110 paired echocardiogram and CPET results to this study, with 1 year interval for repeated examinations. Echocardiography and exercise testing were conducted following standardized procedures, and the data were collected together with clinically relevant indicators for subsequent statistical analysis. Demographic comparisons were performed using t-tests and chi-square tests. Univariate and multivariate analyses were conducted to identify potential predictors of peak oxygen uptake (peak VO2) and the carbon dioxide ventilation equivalent slope (VE/VCO2 slope). Receiver operating characteristic (ROC) analysis was used to assess the performance of the parameters.ResultsThe ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) was found to be the only independent indicator significantly associated with both peak VO2 and VE/VCO2 slope (both p < 0.05). Additionally, left ventricular ejection fraction (LVEF) and right ventricular fractional area change (FAC) were independently correlated with the VE/VCO2 slope (both p < 0.05). TAPSE/PASP showed the highest area under the ROC curve (AUC) for predicting both a peak VO2 ≤ 15 mL/kg/min and a VE/VCO2 slope ≥ 36 (AUC = 0.91, AUC = 0.90, respectively). The sensitivity and specificity of TAPSE/PASP at the optimal threshold exceeded 0.85 for both parameters.ConclusionsTAPSE/PASP may be a feasible echocardiographic indicator for evaluating exercise tolerance.

Exertional Cardiac and Pulmonary Vascular Hemodynamics in Patients With Heart Failure With Reduced Ejection Fraction

BackgroundExertional dyspnea is a cardinal manifestation of heart failure with reduced ejection fraction (HFrEF), but quantitative data regarding exertional hemodynamics are lacking. ObjectivesWe sought to characterize exertional cardiopulmonary hemodynamics in patients with HFrEF. MethodsWe studied 35 patients with HFrEF (59 ± 12 years old, 30 males) who completed invasive cardiopulmonary exercise testing. Data were collected at rest, at submaximal exercise and at peak effort on upright cycle ergometry. Cardiovascular and pulmonary vascular hemodynamics were recorded. Fick cardiac output (Qc) was determined. Hemodynamic predictors of peak oxygen uptake (VO2) were identified. ResultsLeft ventricular ejection fraction and cardiac index were 23% ± 8% and 2.9 ± 1.1 L/min/m2, respectively. Peak VO2 was 11.8 ± 3.3 mL/kg/min, and the ventilatory efficiency slope was 53 ± 13. Right atrial pressure increased from rest to peak exercise (4 ± 5 vs 7 ± 6 mmHg,). Mean pulmonary arterial pressure increased from rest to peak exercise (27 ± 13 vs 38 ± 14 mmHg). Pulmonary artery pulsatility index increased from rest to peak exercise, while pulmonary arterial capacitance and pulmonary vascular resistance declined. ConclusionsPatients with HFrEF suffer from marked increases in filling pressures during exercise. These findings provide new insight into cardiopulmonary abnormalities contributing to impairments in exercise capacity in this population. Clinical Trial Registrationclinicaltrials.gov identifier: NCT03078972

Six-minute walk test may be a reliable predictor of peak oxygen uptake in patients undergoing hemodialysis

BackgroundCardiorespiratory fitness seems to play an important role in the general health of patients undergoing hemodialysis (HD). However, the prediction of peak oxygen uptake (V̇O2peak) in a clinical setting is not widely adopted for these patients.ObjectivesEvaluate the agreement and reliability between directly and indirectly V̇O2peak measurements in patients undergoing HD.MethodsThis is a cross-sectional study with patients undergoing HD that performed a cardiopulmonary exercise test (CPET) with 5/10 watts incremental load in each minute using a cycle ergometry to directly evaluate the V̇O2peak, and the 6-min walk test (6MWT) in a 30-m corridor to indirect measures it. Both tests were performed on a midweek non-dialysis day. Bland–Altman analysis of agreement limits was used with direct and indirect V̇O2peak values. Intraclass correlation coefficient (ICC) and Cronbach’s Alpha was used to evaluate the reproducibility and reliability between direct and indirect V̇O2peak values.ResultsTwenty-six patients (54.4 ± 14.5 years, 53.8% of male) were evaluated. The V̇O2peak direct mean obtained through CPET was 15.91 ± 5.26 (ml/kg/min), while the indirect mean obtained through 6MWT was V̇O2peak of 14.89 ± 4.21 (ml/kg/min). There was a strong positive correlation between both V̇O2peak values (r = 0.734; p < 0.001). The Bland–Altman analysis demonstrated that the methods agreed with each other (p = 0.103). Also, the ICC (0.829) and Cronbach's Alpha (0.846) showed excellent reproducibility and reliability.Conclusions6MWT is a reliable tool for estimating V̇O2peak in patients undergoing HD.

Comparison of Cardiorespiratory Fitness in Black or African American Versus Caucasian Patients With Heart Failure.

Cardiopulmonary exercise testing (CPX) is a well-established assessment with important insight into prognosis and therapeutic efficacy in patients with heart failure (HF). Prior studies have identified several clinical differences between Black or African American (B-AA) and Caucasian patients with HF. Differences in key CPX responses between these two groups require further investigation. Using a database consisting of subjects with symptomatic HF who had undergone CPX for inclusion in various prospective randomized clinical trials, we identified 198 (n = 94 [47%] B-AA; n = 105 [53%] Caucasian) patients with a qualifying baseline CPX. Significant univariate predictors of peak oxygen uptake (V˙o2peak) were included in a multivariate linear regression model. When compared with Caucasian patients, B-AA were younger (mean ± SD = 54.8 ± 10.0 vs 57.9 ± 9.6 yr, P = .03), had higher C-reactive protein (CRP) (median [IQR] = 4.9 [2.3, 8.8] vs 1.9 [0.6, 5.5] mg/L, P < .0001), lower hemoglobin (13.0 ± 1.8 vs 13.8 ± 1.6 g/dL, P = .003), and lower left ventricular ejection fraction (LVEF) (40 [32, 51] vs 53 [43, 59]%, P < .00010). During CPX, B-AA patients also had lower V˙o2peak (14.6 ± 3.9 vs 17.6 ± 4.8 mL·kg-1·min-1, P < .0001). No differences were observed between B-AA and Caucasian in the minute ventilation/carbon dioxide production (V˙e/V˙co2) slope (P = .14). The difference in V˙o2peak between B-AA and Caucasian was largely attenuated after adjusting for age, body mass index, CRP, N-terminal pro-brain natriuretic peptide, hemoglobin, LVEF, and peak HR (14.1: 95% CI, 13.2-14.9 vs 15.6: 95% CI, 14.4-16.8 mL·kg-1·min-1, P = .053). Directly measured V˙o2peak was significantly lower in B-AA than in Caucasians with HF. This is largely explained by differences in clinical characteristics, whereas no significant differences were observed in the V˙e/V˙co2 slope.

Knee extensor muscle strength as a predictor of peak oxygen uptake in patients with heart disease.

[Purpose] The mortality rate increases when peak oxygen uptake is less than 5 metabolic equivalents, and peak oxygen uptake correlates with knee extensor muscle strength. This study aimed to determine the knee extensor muscle strength at peak oxygen uptake corresponding to 5 metabolic equivalents. [Participants and Methods] We enrolled 45 consecutive patients (29 males and 16 females; average age, 63.6 ± 13.7 years) with heart disease receiving outpatient rehabilitation with us. We performed cardiopulmonary exercise testing with a bicycle ergometer to measure peak oxygen uptake. We investigated the relationship between peak oxygen uptake and isometric knee extensor muscle strength divided by the body weight (kgf/kg). The cutoff value for knee extensor muscle strength with peak oxygen uptake corresponding to 5 metabolic equivalents was calculated. [Results] Knee extensor muscle strength was significantly positively associated with peak oxygen uptake. The cutoff value for knee extensor muscle strength at peak oxygen uptake corresponding to 5 metabolic equivalents was 0.46 kgf/kg. [Conclusion] In this study, the cutoff value for knee extensor muscle strength for achieving peak oxygen uptake corresponding to 5 metabolic equivalents in patients with heart disease was 0.46kgf/kg.

Relationship between Cardiac Remodeling and Exercise Capacity in Elite Athletes: Incremental Value of Left Atrial Morphology and Function Assessed by Three-Dimensional Echocardiography

Data are scarce regarding left atrial (LA) adaptation to regular physical exercise. The aim of this study was to examine left ventricular (LV) and also LA morphologic and functional remodeling in elite athletes using three-dimensional (3D) echocardiography. In this retrospective analysis, the study group consisted of 138 elite athletes (mean age, 20±4years; 62% men) and 50 sedentary control subjects. Electrocardiographically gated full-volume 3D data sets were obtained for offline analysis using dedicated software for 3D LA and LV measurements. Body surface area-indexed LA maximal volume (LAVmax) and LV end-diastolic volume were determined. LA total emptying fraction, LA passive and LA active emptying fraction, and LV global longitudinal strain were also calculated. Athletes also underwent cardiopulmonary exercise testing to determine peak oxygen uptake. Athletes demonstrated higher 3D LAVmax (32±6 vs 26±8mL/m2) and indexed LV end-diastolic volume (85±12 vs 62±10mL/m2) compared with control subjects (P<.001 for both). Functional measures of the left ventricle and left atrium, such as the absolute value of 3D LV global longitudinal strain (19±2% vs 22±2%), LA total emptying fraction (58±6% vs 64±6%), and active emptying fraction (24±10% vs 32±10%) were lower in athletes (P<.001 for all). Male athletes had higher indexed LV end-diastolic volume compared with female athletes (89±13 vs 80±8mL/m2, P<.001), but LAVmax did not differ between genders (32±6 vs 33±5mL/m2, P=.18). Besides heart rate, gender, and body surface area, 3D LAVmax, LV global longitudinal strain, and LA passive emptying fraction were independent predictors of peak oxygen uptake. Regular physical exercise results in marked LA and LV remodeling with considerable gender differences as explored by 3D echocardiography. In contrast with various cardiovascular diseases, more pronounced LA dilation and lower resting functional measures are associated with better exercise performance.

Clinical and Rehabilitative Predictors of Peak Oxygen Uptake Following Cardiac Transplantation.

The measurement of peak oxygen uptake (VO2peak) is an important metric for evaluating cardiac transplantation (HTx) eligibility. However, it is unclear which factors (e.g., recipient demographics, clinical parameters, cardiac rehabilitation (CR) participation) influence VO2peak following HTx. Consecutive HTx patients with cardiopulmonary exercise testing (CPET) between 2007–2016 were included. VO2peak was measured from CPET standard protocol. Regression analyses determined predictors of the highest post-HTx VO2peak (i.e., quartile 4: VO2peak > 20.1 mL/kg/min). One hundred-forty HTx patients (women: n = 41 (29%), age: 52 ± 12 years, body mass index (BMI): 27 ± 5 kg/m2) were included. History of diabetes (Odds Ratio (OR): 0.17, 95% Confidence Interval (CI): 0.04–0.77, p = 0.021), history of dyslipidemia (OR: 0.42, 95% CI: 0.19–0.93, p = 0.032), BMI (OR: 0.90, 95% CI: 0.82–0.99, p = 0.022), hemoglobin (OR: 1.29, 95% CI: 1.04–1.61, p = 0.020), white blood cell count (OR: 0.81, 95% CI: 0.66–0.98, p = 0.033), CR exercise sessions (OR: 1.10, 95% CI: 1.04–1.15, p < 0.001), and pre-HTx VO2peak (OR: 1.17, 95% CI: 1.07–1.29, p = 0.001) were significant predictors. Multivariate analysis showed CR exercise sessions (OR: 1.10, 95% CI: 1.03–1.16, p = 0.002), and pre-HTx VO2peak (OR: 1.16, 95% CI: 1.04–1.30, p = 0.007) were independently predictive of higher post-HTx VO2peak. Pre-HTx VO2peak and CR exercise sessions are predictive of a greater VO2peak following HTx. These data highlight the importance of CR exercise session attendance and pre-HTx fitness in predicting VO2peak post-HTx.

Prediction of peak oxygen uptake using the modified shuttle test in children and adolescents with cystic fibrosis.

Several tests may be used to assess exercise intolerance in cystic fibrosis (CF), including the gold standard cardiopulmonary exercise test (CPET) and the Modified Shuttle Test (MST). To evaluate the use of the MST as a predictor of peak oxygen uptake (VO2 peak) and to compare VO2 peak and maximal heart rate (HRmax) obtained in both tests. Cross-sectional study including individuals with CF aged between 6 and 20 years old. Participants who were unable to perform the tests and/or presented signs of pulmonary exacerbation were excluded. Demographic, anthropometric, clinical and spirometric values ​​were collected. CPET and the MST were performed in two consecutive outpatient visits. HRmax, peripheral oxygen saturation, dyspnea, and VO2 peak measured and estimated were compared. Twenty-four patients, mean age 15.7 ± 4.2 years and FEV1 (% predicted) 76.4 ± 23.8, were included. Mean values ​​of HRmax (bpm) and HRmax in percent of predicted (HRmax%) were lower (P = 0.01) in the MST (171.6 ± 14.5 and 87.1 ± 7.5) compared to CPET (180.9 ± 10.0 and 91.9 ± 5.4). However, there was no significant differences between tests in the variation (delta) for HRmax and HRmax% (P = 0.17). A strong correlation (r = 0.79; P < 0.0001) was found between distance achieved (MST) and VO2 peak (CPET). The regression model to estimate VO2 peak resulted in the following equation: VO2 (mL · kg-1 · min-1 ) = 20.301 + 0.019 × MST distance (meters). There was no difference (P = 0.50) between VO2 peak measured (CPET) and estimated by the equation. The MST may be an alternative method to evaluate exercise capacity and to predict VO2 peak in children and adolescents with CF.

Left ventricular end-diastolic dimension and septal e\u2032 are predictors of cardiac index at rest, while tricuspid annular plane systolic excursion is a predictor of peak oxygen uptake in patients with pulmonary hypertension

Little is known regarding a correlation of hemodynamics at rest or exercise capacity with echocardiographic parameters in patients with pulmonary hypertension (PH). To clarify these potential correlations, we performed transthoracic echocardiography, right heart catheterization, and cardiopulmonary exercise testing in 53 patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Left ventricular end-diastolic dimension (LVDd), early diastolic velocity of the septal mitral annulus (septal e′), tricuspid regurgitation peak gradient (TRPG), and tricuspid annular plane systolic excursion (TAPSE) were significantly correlated with cardiac index (LVDd; r = 0.477, P < 0.001, septal e′; r = 0.463, P = 0.001, TRPG; r = − 0.455, P = 0.001 and TAPSE; r = 0.406, P = 0.003, respectively). Multiple regression analysis revealed that LVDd and septal e′ were significantly associated with cardiac index (CI) and stroke volume index at rest. Among the exercise capacity markers evaluated, TAPSE, TRPG, and LVDd were significantly correlated with peak oxygen uptake (TAPSE; r = 0.534, P < 0.001, TRPG; r = − 0.466, P = 0.001 and LVDd; r = 0.411, P = 0.002, respectively). Multiple regression analysis showed that TAPSE was significantly associated with peak oxygen uptake (VO2). In PAH and CTEPH patients, LVDd and septal e′ were significantly associated with CI at rest, whereas TAPSE was significantly associated with peak VO2. Echocardiographic parameters may predict the prognostic factors of PAH and CTEPH patients.

Right ventricular dyssynchrony and exercise capacity in idiopathic pulmonary arterial hypertension.

Survival in patients with pulmonary arterial hypertension (PAH) is determined by right ventricular (RV) function adaptation to afterload. How altered RV function impacts on exercise capacity in PAH is not exactly known.104 idiopathic PAH (IPAH) patients aged 52±14 years underwent a diagnostic right heart catheterisation, a comprehensive echocardiography including two-dimensional speckle tracking for RV dyssynchrony evaluation and a cardiopulmonary exercise test. Multivariate analyses were performed to identify independent predictors of peak oxygen uptake (peak V'O2 ).A first multivariate analysis of only resting haemodynamic variables identified cardiac index, right atrial (RA) pressure and pulmonary arterial compliance as independent predictors, with low predictive capacity (r2=0.31; p<0.001). A second multivariate analysis model which considered only echocardiographic parameters but without RV dyssynchrony, identified RV fractional area change (FAC) and RA area as independent predictors with still low predictivity (r2=0.35; p<0.001). Adding RV dyssynchrony to the second model increased its predictivity (r2=0.48; p<0.001). Repetition of the three multivariate analyses in patients with preserved RVFAC confirmed that inclusion of RV dyssynchrony results in the highest predictive capability of peak V'O2 (r2=0.53; p=0.001).A comprehensive echocardiography with speckle tracking-derived assessment of the heterogeneity of RV contraction improves the prediction of aerobic exercise capacity in IPAH.

Predicting Peak Oxygen Uptake From the 6-Minute Walk Test in Patients With Pulmonary Hypertension.

To determine whether the 6-minute walk test (6MWT) is a predictor of peak oxygen uptake ((Equation is included in full-text article.)O2) in patients with idiopathic pulmonary arterial hypertension (IPAH). A total of 157 patients treated for IPAH completed a 6MWT in accordance with American Thoracic Society standards. Heart rate, pulse oximetry, and Borg rating of perceived exertion were determined at baseline and posttest. A cardiopulmonary exercise test (CPET) was performed on a cycle ergometer using a ramp protocol. Participants were stratified post hoc by age into 3 groups: children (n = 26), adolescents (n = 49), and adults (n = 82). Multiple linear regression analysis was performed to predict peak (Equation is included in full-text article.)O2 from the 6MWT. The regression equation generated for the children was the only model to strongly predict peak (Equation is included in full-text article.)O2 (r = 0.87; P < .001). Similar models for adolescent (r = 0.59; P < .001) and adult groups (r = 0.68; P < .001) did not achieve the same level of correlation. Six-Minute Walk Test was able to accurately predict peak (Equation is included in full-text article.)O2 in children (6-12 years) with IPAH; however, the model was weaker for predicting peak (Equation is included in full-text article.)O2 in older populations. These findings suggest that 6MWT may be as valid a test for predicting peak (Equation is included in full-text article.)O2 in children with IPAH as CPET measured peak (Equation is included in full-text article.)O2. In older IPAH populations, CPET is the only reliable method for the evaluation of peak (Equation is included in full-text article.)O2.

Cardiopulmonary exercise testing in healthy children and adolescents at moderately high altitude

Cardiopulmonary exercise testing is a tool that helps clinicians to establish diagnosis and calculate risk stratification in adults. However, the utility of this test among children with congenital heart disease has not been fully explored. The goal of this study was to describe reference values for cardiopulmonary performance of healthy children. This study included 103 apparently healthy children (aged from 4 to 18 years; 61 boys), who underwent cardiopulmonary test using a treadmill protocol. All tests took place at 2240m above sea level (Mexico City). Exercise time was 11±4min. There were no complications. Peak oxygen uptake correlated closely with height in both genders (girls r=0.84; boys r=0.84, p<0.001). A multivariable linear regression model showed that body surface area, exercise time, gender and heart rate reserve were significant predictors of peak oxygen uptake (R(2)=0.815, p<0.001). Peak oxygen uptake was strongly associated with age even among children younger than thirteen years (r=0.74, p<0.001). This study provides physiological values for the major cardiopulmonary variables obtained from exercise testing using a treadmill among healthy children. Cardiopulmonary exercise test can be safely and effectively performed in young children even as young as 4 years old. Variables including age, gender and height are strongly associated with exercise time, peak heart rate and peak oxygen uptake. Regression equations for predicting peak heart rate and peak oxygen uptake are presented as reference values that allow researchers to compare children with heart disease versus those who are healthy.

Physical Activity as a Long-Term Predictor of Peak Oxygen Uptake

A physically active lifestyle and a relatively high level of cardiorespiratory fitness are important for longevity and long-term health. No population-based study has prospectively assessed the association of physical activity levels with long-term peak oxygen uptake (VO(2peak)). 1843 individuals (906 women and 937 men) who were between 18 and 66 yr at baseline and were free from known lung or heart diseases at both baseline (1984-1986) and follow-up (2006-2008) were included in the study. Self-reported physical activity was recorded at both occasions, and VO(2peak) was measured at follow-up. The association of physical activity levels and VO(2peak) was adjusted for age, level of education, smoking status, and weight change from baseline to follow-up, using ANCOVA statistics. The level of physical activity at baseline was strongly associated with VO(2peak) at follow-up 23 yr later in both men and women (Ptrends < 0.001). Compared with individuals who were inactive at baseline, women and men who were highly active at baseline had higher (3.3 and 4.6 mL·kg(-1)·min(-1)) VO(2peak) at follow-up. Women who were inactive at baseline but highly active at follow-up had 3.7 mL·kg(-1)·min(-1) higher VO(2peak) compared with women who were inactive both at baseline and at follow-up. The corresponding comparison in men showed a difference of 5.2 mL·kg(-1)·min(-1) (95% confidence interval = 3.1-7.3) in VO(2peak). Physical activity level at baseline was positively associated with directly measured cardiorespiratory fitness (VO(2peak)) 23 yr later. People who changed from low to high activity during the observation period had substantially higher V˙O(2peak) at follow-up compared with people whose activity remained low.

Exercise Performance After Surgery for Pulmonary Atresia and Intact Ventricular Septum

The objective of this study was to assess exercise performance in subjects born in Sweden between 1980 and 1995 and undergoing surgery for pulmonary atresia and intact ventricular septum and to identify determinants of exercise performance. Twenty-seven subjects, 16 with biventricular repair and 11 with univentricular palliation, and 28 age- and sex-matched controls completed cardiopulmonary exercise and lung function testing. Peak oxygen uptake was determined using a symptom-limited ramp bicycle exercise protocol. Regression analysis was performed to identify predictors of peak oxygen uptake (V'O(2)), The index group had lower peak V'O(2) (1.4 [median 0.8; range 2.5] l/min) than controls (1.9 [0.7; 3.1]; p < 0.05). Subjects without ventriculocoronary arterial communications (VCAC), corrected to biventricular circulation, had higher peak V'O(2), than the remaining index subjects. Decreased total lung capacity, low minute ventilation, and high physiologic dead space measured at peak exercise were all independent determinants of low peak V'O(2) Exercise capacity is generally decreased in subjects with pulmonary atresia and intact ventricular septum, although there are marked interindividual differences. Good exercise capacity was found in subjects without VCAC who had undergone biventricular repair. Decreased lung function was an unfavourable predictor of exercise capacity.

Tissue Doppler imaging adds incremental value in predicting exercise capacity in patients with congestive heart failure

Left ventricular (LV) systolic and diastolic parameters derived from Doppler echocardiography have been used widely to predict functional capacity but diastolic filling is affected by various factors. Tissue Doppler imaging (TDI) that records systolic and diastolic velocities within the myocardium and at the corners of the mitral annulus, has been shown to provide additional information about regional and global LV function. The goal of this study was to examine whether TDI-derived parameters add incremental value to other standard Doppler echocardiographic measurements in predicting exercise capacity. The study enrolled 59 consecutive patients with stable congestive heart failure (CHF). The etiology of heart failure was coronary artery disease in 42 patients and dilated cardiomyopathy in 17. Twenty-three age-matched healthy subjects were recruited as controls. Conventional echocardiographs and TDI were obtained. Early (Ea) and late (Aa) diastolic and systolic (Sa) mitral annulus velocities, the Ea/Aa and E/Ea ratios, were measured by pulsed wave TDI placed at the septal side of the mitral annulus and results were compared with results of cardiopulmonary exercise testing. Systolic and early diastolic velocities of mitral annulus were decreased and the E/Ea ratio was increased in the restrictive group as compared to controls (P = 0.02, P = 0.03, P < 0.001, respectively) but there was no significant difference in late diastolic velocity and the Ea/Aa ratio between the restrictive group and controls. The average peak VO2 of the patients were 14.9 +/- 4.9 ml/min per kg. Achieved peak VO2 of the patients with E/Ea ratio <or=7.5 was 17.4 +/- 5 vs 12.2 +/- 3 ml/min per kg for those with E/Ea >7.5 (P < 0.001). Interestingly, the patients with the nonrestrictive pattern and E/Ea ratio >7.5 had reduced exercise capacity, as did the group with restrictive LV filling patterns (12.8 +/- 3.3 vs 12.9 +/- 4.0 ml/min per kg, P = 0.9). Similarly, there was no significant difference in the mean exercise capacity between the patients with a nonrestrictive pattern vs restrictive pattern with E/Ea ratio <or=7.5 (16.1 +/- 5.0 vs 15.4 +/- 5.1 ml/min per kg, P = 0.78). Univariate analysis demonstrated that the peak Sa (r = 0.30, P = 0.03), peak Ea (r = 0.38, P = 0.004) and peak Aa (r = 0.35, P = 0.009) correlated significantly with maximum exercise capacity. No relationship was observed between the Ea/Aa ratio and peak VO2 (r = -0.09, P = 0.48). By multivariate analysis, including age and heart rate, the E/Ea ratio was found to be an independent prognostic factor at peak VO2 (P < 0.001. In contrast, the comparison of the maximum transmitral early diastolic velocity and the mitral annulus TDI velocity, that is E/Ea ratio, had strong correlation with peak VO2 (r = -0.46, P < 0.001). Receiver operating characteristic (ROC) analysis was performed for prediction of limited exercise capacity from the E/Ea ratio. An E/Ea ratio <or=7.5 was able to predict peak VO2 <or=14 ml/min per kg with a sensitivity of 84% and a specificity of 74%. If restrictive pattern or an E/Ea ratio >7.5 was used, 21 out of 24 patients in the reduced exercise capacity group were identified with 16 false positives in the preserved exercise capacity group (P = 0.001). Mitral annular systolic and diastolic velocities of TDI were associated with cardiopulmonary exercise capacity in patients with LV systolic dysfunction. Index of the E/Ea ratio was found to be the most powerful predictor of peak oxygen uptake.

Prospective evaluation of the oxygen uptake efficiency slope as a submaximal predictor of peak oxygen uptake in aged patients with ischemic heart disease

The purpose of this study was to evaluate the oxygen uptake efficiency slope (OUES) as a predictor of peak oxygen consumption (VO2) in aged patients with coronary artery disease (CAD) and to compare its predictive value to that of ventilatory anaerobic threshold (VAT). A total of 160 aged (>60 years) patients with stable CAD performed a maximal cardiopulmonary exercise test. The equations were computed by using data of 85 randomly selected patients and were validated in the remaining 75 patients. Bland-Altman (BA) analysis was used to assess the agreement between measured and predicted peak VO2. In the first 85 patients, peak VO2 correlated best with VAT and OUES per kilogram (P < .001). The linear regression to predict peak VO2 for OUES per kilogram was peak VO2 = 4.591 + 0.64 x OUES/kg (SEE = 2.61 mL kg(-1) min(-1)). The BA 95% limits of agreement were -29% and +30% of the predicted value. For VAT, the linear regression to predict peak VO2 was peak VO2 = 2.995 + 1.251 x VAT (SEE = 2.26 mL kg(-1) min(-1)). The BA 95% limits of agreement were -23% and +33% of the predicted value. Cross-tabulation analysis in 3 subgroups with different exercise capacities showed significant relationship between predicted and measured peak VO2 (all P < .001). OUES per kilogram showed the best measure of agreement with measured peak VO2, resulting in high sensitivity and specificity scores. OUES is not able to acceptably predict peak VO2 in aged patients with CAD but is at least as performant as VAT in categorizing patients into subgroups with different exercise capacities. Therefore, the objectively measurable OUES is the preferred submaximal predictor of functional capacity in the assessment of aged patients with CAD.

Poor Relationship Between Exercise Capacity and Spirometric Measurements in Patients With More Symptomatic Heart Failure

Background The origin of exercise limitation in patients with chronic heart failure (CHF) is multifactorial, and the relative contributions of different abnormalities may vary with severity of heart failure symptoms. The aim of the current study was to determine the extent to which spirometric indices predict peak exercise capacity in patients with differing severity of symptoms. Methods and Results A total of 340 patients with left ventricular systolic dysfunction underwent spirometry, and a ramped, maximal exercise treadmill test with metabolic gas exchange measurements. For comparative purposes, a group of 174 aged-matched controls with no major structural heart disease (MSHD) was also included. In a stepwise linear regression model, forced expiratory volume in 1 second (FEV 1) and forced vital capacity (FVC) were independent predictors of peak oxygen uptake ( p V ˙ O 2 ) in controls ( r 2 = 18–25%; P = .001) and New York Heart Association (NYHA) I-II patients ( r 2 = 16–18%; P = .001). No association between spirometric indices (FEV 1/FVC) and p V ˙ O 2 ( r 2 = 1–2%; P > .05) was found in NYHA III-IV patients. Conclusion In aged-matched controls with no MSHD, spirometric variables (FEV 1/FVC) explain 18% to 25% of the variance in p V ˙ O 2 , and 16% to 18% of the variance in patients with NYHA class I-II symptoms. As symptoms worsen, the influence of spirometric variables on peak exercise capacity diminishes, and there is no such relation in the NYHA class III-IV patients.

Physiological parameters during the initial stages of cardiopulmonary exercise testing in patients with chronic heart failure. Their value in the assessment of clinical severity and prognosis.

To analyse the relationship between initial exercise parameters and peak oxygen consumption and prognosis in 96 patients with congestive heart failure. Comparison of responses during the initial 6 min of cardiopulmonary exercise testing (Naughton modified protocol) in patients stratified to the Weber classification, and analysis of their predictive value with respect to peak oxygen uptake and prognosis. All patients had a left ventricular ejection fraction < 0.45 and a valid cardiopulmonary exercise test, during which they remained in sinus rhythm. Significant differences in several parameters were seen in the initial stages, including oxygen pulse (P < 0.04) and ventilation equivalent for oxygen (P < 0.004). These parameters remained as independent predictors of peak oxygen uptake in the algorithm derived from baseline and initial stage variables. In a multivariate Cox proportional hazards model, the predicted peak oxygen uptake (P < 0.003) was an independent predictor of mortality. In patients with congestive heart failure, the initial 6 min parameters of a cardiopulmonary exercise test have additional value in the assessment of clinical severity and prognosis. This may be of clinical relevance since a limited incremental exercise protocol may be more objective than more traditional 6 min walking tests and less demanding.

The Reliability and Validity of the 20-Meter Shuttle Test as a Predictor of Peak Oxygen Uptake in Edinburgh School Children, Age 13 to 14 Years

This study examined the reliability and validity of the 20-meter shuttle test as a predictor of peak VO2 in Edinburgh school children. Thirty-three children (15 boys, 18 girls) performed three shuttle tests and three laboratory treadmill tests of peak VO2. Multiple regression analysis revealed that the prediction of peak VO2 (ml·kg−1·min−1) from shuttle run performance was improved by including skinfold thickness measurements in the prediction models, particularly with the female group. Predictive power was greatest for females when using maximal shuttle speed (kmhr−1) best of three repeat tests and triceps skinfold thickness (mm) (R2 = .85, SEE = 2.4), and for males when using maximal shuttle speed (km·hr−1) best of three repeat tests and the sum of the triceps and subscapular skinfolds (R2 = .68, SEE = 3.23). When using shuttle run performance to predict peak VO2 (ml·kg−1·min−1) in children of this age group, body composition measures must be included in the equation.