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International audience; Introduction Cardio-pulmonary exercise test (CPET) is becoming a key examination to assess physical capacity and disease severity in paediatric cardiology. The VE/VCO2 slope has been increasingly used as a surrogate marker for morbidity and mortality in adult heart failure, pulmonary arterial hypertension and for adult patients with CHD. Nevertheless, the use of the VE/VCO2 slope in children remains limited in the absence of reference values and clearly identified clinical determinants. This study aimed to compare the VE/VCO2 slope in a paediatric cohort with CHD to that of age- and gender-adjustedhealthy controls. We also intended to identify the clinical and CPET variables associated with VE/VCO2 slope in this population. Methods This cross-sectional study was carried out between November 2010 and September 2015 in two tertiary care paediatric cardiology reference centres. Results A total of 700 children were enrolled (399 CHD and 301 healthy controls). The mean VE/VCO2 slope was significantly higher in CHD than in healthy subjects (31.6±4.8 vs. 29.3±4.8; P

Objective The ventilation-to-carbon dioxide output (VE/VCO2) slope could predict morbidity and mortality after lung resection. The aim of the study was to identify whether VE/VCO2 slope obtained from cardiopulmonary exercise test (CPET) was an independent predictor of cardiopulmonary complications after anatomical pulmonary resection by video-assisted thoracic surgery (VATS). Methods We reviewed the files of all consecutive patients that underwent pulmonary anatomical resections by VATS between January 2010 and October 2020. The data were extracted from the registry of the Centre for Thoracic Surgery of Western Switzerland. Pneumonectomies were excluded from the study. We used a multivariable Cox regression to investigate the risk of cardiopulmonary complications associated with the VE/VCO2 slope and other possible confounders, including the Charlson Comorbidity Index (CCI), the CPET data and pulmonary functions. Results In total, 1392 patients (mean age: 66±11 years; ratio female: 47%) underwent anatomical resection by VATS. CPET was performed in 204 patients (15%). However, the VE/VCO2 slope data were available in 145 patients, which were included for the analysis. Patients underwent segmentectomies (N = 42) and lobectomies (N = 101) mainly for lung cancer (96%). The average percentage of the predicted VO2max was of 70±17%. Maximal effort during the CPET (respiratory coefficient ratio >1.1) was not reached in 30% of patients, without impact on the VE/VCO2 slope (39±6 vs 37±7, P = 0.21). Cardiopulmonary complications appeared in 32% of patients with no mortality at 90 days. In the multivariate analysis, VE/VCO2 slope >35 was correlated with cardiopulmonary complications (OR 3.5, 95% CI [1.3-9.3], P = 0.012). CCI, pulmonary functions, peak VO2 and the extension of the anatomical resection was not associated with cardiopulmonary complications. Conclusion VE/VCO2 slope above 35 predicts postoperative cardiopulmonary complications in anatomical resections by VATS. The VE/VCO2 slope is independent of the intensity of effort during the CPET. The impact of prehabilitation on the slope should be determined.

Ventilation/carbon dioxide production (VE/VCO2slope) is used clinically to determine cardiorespiratory fitness and morbidity in heart failure (HF). Previously, we demonstrated that lower lean leg mass is associated with high VE/VCO2slope during exercise in HF. In healthy individuals, we evaluated 1) whether VE/VCO2slope differed between lean and overweight women and 2) the relationship between lean leg mass and VE/VCO2slope in overweight sedentary (OWS), overweight trained (OWTR) and lean, trained (LTR) women. Methods: Gas exchange and ventilation were collected during a treadmill peak oxygen uptake test (VO2peak) in 40 women [26 OWS (29 ± 7 yrs., mean ± SD), 7 OWTR (33 ± 5 yrs) and 7 LTR (26 ± 6 yrs)]. Body composition was measured by dual X-ray absorptiometry. Results: VO2peak was highest in LTR (46.6 ± 8 ml/kg/min) compared with OWTR (38.1 ± 4.9 ml/kg/min) and OWS women (25.3 ± 4.8 ml/kg/min, p 0.05). Higher lean leg mass was associated with lower VE/VCO2slope in overweight women (OWS + OWTR: r = −0.55, p

Background The ventilatory efficiency represented cardiovascular, pulmonary, and musculoskeletal performance into an integrate index has been used as long-term and short-term prognostic variables in congestive heart failure. The heart failure patients post heart transplantation, whether the ventilatory efficiency was also normalized is still unknown. Methods This was a cross-sectional study. We measured ventilation to carbon dioxide production slope and oxygen consumption in peak exercise (peak VO2) by cardiopulmonary exercise test, which represented ventilatory efficiency and functional capacity respectively. Strength of hand grip, the 30-second chair stand test, and 6-minute walking test were also evaluated. Patients with ventilation to carbon dioxide production slope Results There were 51 clinically stable post-heart transplantation patients (age 53 ± 12.4 years; 86.3% were male) at 65.14 ± 41.17 months after transplantation. The ventilation to carbon dioxide production slope was 29.2 ± 5.6, which significantly improved compared to that recorded 1 month after heart transplantation (32.6 ± 6.4). There were 20 patients in the abnormal group, characterized by lower 6-minute walking test distance (normal vs abnormal, 422.5 ± 97.8 vs 532.6 ± 87.6 m) and peak VO2 (normal vs abnormal, 14.9 ± 5.3 vs 18.8 ± 5.1 mL/kg/min). The abnormal ventilation to carbon dioxide production slope was significantly correlated with 6-minute walking test distances in multivariate analyses. Conclusion Our findings indicate that the ventilation to carbon dioxide production slope is partially abnormal among patients post-heart transplantation. A ventilation to carbon dioxide production slope above the normal range is characterized by a lower peak VO2 during cardiopulmonary exercise test and lower 6-minute walking test distance. The ventilation to carbon dioxide production slope is also significantly negatively correlated with peak VO2, peak work rate, and 6-minute walking test distance. The prognostic utility of the ventilation to carbon dioxide production slope for patients post-heart transplantation requires further investigation.

A high slope of the ventilation vs. carbon dioxide relationship (VE/VCO₂ slope) during incremental exercise has been reported in several congenital heart disease (CHD) types, but it is not clear whether the main cause of high VE/VCO₂ slope is excessive ventilation or reduced perfusion.We studied 169 adolescent and adult patients with repaired, noncyanotic CHD, divided into 2 groups according to VE/VCO₂ slope %predicted values (≤120 and120), and 15 age- and sex-matched normals. VCO₂/VE max and VO₂/VE max were considered proxies of the perfusion/ventilation relationship, with VCO₂ and VO₂ as indirect descriptors of cardiac output.VCO₂/VE max was significantly and inversely related to VE/VCO₂ slope (r=-0.73, p0.0001), and higher in normals and ≤120 than in120 (39.6 ± 7.7, 36.1 ± 5.3 and 28.5 ± 4.1, respectively, p0.0001). Similarly, VCO₂ at VCO₂/VE max was higher in normals and ≤120 than in120 (1701 ± 474, 1480 ± 492 and 1169 ± 388 ml/min, respectively, p0.0001), whereas ventilation at VCO₂/VE max showed no changes (43 ± 8, 41 ± 12, 41 ± 11 and 41 ± 9l/min, respectively, p=0.82) between groups. Thus, differences in VCO₂/VE max and VE/VCO₂ slope between groups were due mostly to changes in VCO₂, i.e. in cardiac output, rather than ventilation. The same behavior was observed for VO₂/VE max.A high VE/VCO₂ slope observed in patients with repaired, noncyanotic CHD seems not to depend on excessive ventilation but on hypoperfusion due to impaired cardiac output response to incremental exercise. This finding should focus researchers' attention mainly on the heart when addressing exercise pathophysiology of this patient population.

The minute ventilation/carbon dioxide production (VE/VCO2) slope has been widely demonstrated to have strong prognostic value in patients with chronic heart failure (CHF), and the risk of mortality is believed to increase when the VE/VCO2 slope is >32.8; however, there is little evidence concerning the prognostic value of the VE/VCO2 slope in Chinese patients. In the present study, the prognostic value of the VE/VCO2 slope was investigated in patients with CHF. A total of 258 subjects underwent symptom-limited cardiopulmonary exercise testing (CPET) and were divided into CHF (113 males and 16 females; LVEF

Peak exercise oxygen uptake (peakVO2) is a widely used prognosticator. Novel spirometric parameters, less affected by submaximal performance, such as the rate of increase of minute ventilation per unit decrease of carbon dioxide production (VE/VCO2 slope) and the oxygen uptake efficiency slope (OUES) have recently been introduced.To evaluate the discriminative value of OUES, as compared to VE/VCO2 slope in patients with coronary artery disease (CAD) and intermediate peakVO2 values.Bicycle spiroergometry was applied in 214 patients with CAD (age 67+/-8 years, 85% men). OUES was strongly related to peakVO2 (r=0.79). New York Heart Association (NYHA) class, 6-min walking distance, N-terminal pro-brain natriuretic peptide (NT-proBNP), inflammatory markers, left ventricular (LV) volumes and ejection fraction were evaluated. NT-proBNP levels predicted independently VE/VCO2-slope and OUES. Patients with intermediate peakVO2 (12-18 ml/kg per min) and increased VE/VCO2-slope (or = 35) had higher NYHA class, lower walking distance, higher NT-proBNP levels and higher LV volumes as compared to patients with a similar peakVO2 but lower VE/VCO2-slope. Similar findings were found for patients with intermediate peakVO2 and high OUES/kg (median value15.3).In CAD patients, OUES was strongly correlated with peakVO2. Both VE/VCO2 slope and OUES were independently associated with NT-proBNP levels. Both VE/VCO2 slope and OUES/kg were able to identify a subgroup of patients with an intermediate peakVO2 that was characterized by advanced remodelling and a higher degree of neurohumoral activation.

We hypothesized that the slope of relation ventilation to carbon dioxide output ( V’E/ V’CO2-slope) could be predictive already during the very first days after submassive pulmonary embolism (PE) to right ventricular systolic pressure (RVsys by echocardiography) after 6 months. We evaluated 21 hemodynamically stable patients at admittance, at days 3, 7, 90, and 180 by cardiopulmonary exercise testing and echocardiography. V’E/ V’CO2-slope (48.4 ± 10.8) decreased within the first week (43.0 ± 9.8 at day 7) and normalized until follow-up at 6 months (35.0 ± 11.3; P -4), p(a-ET)CO2 remained abnormal between days 1 and 3 (5.0 ± 3.9 to 6.7 ± 5.3 mmHg). RVsys declined from 41.7 ± 14.3 to 26.3±13.1 mmHg ( P –4) at 6 months. V’E/ V’CO2-slope ( r²= 0.27; P sys ( r² = 0.28; P = .03) at day 7 correlated with RVsys at 6 months. p(a-ET)CO2, p(a-ET)O2, V’D/ V’T were not related to RVsys after 6 months. RVsys 6 months after acute PE is positively correlated with the V’E/ V’CO2-slope at day 7.

Cardiopulmonary exercise testing and prognostic assessment of hypertensive cardiomyopathy: An emerging application Alberto Dominguez-Rodriguez ⁎, Eduardo Arroyo-Ucar , Pedro Abreu-Gonzalez , Maria Carrillo-Perez Tome , Celestino Hernandez-Garcia , Maria del Carmen Garcia-Baute , Pablo Avanzas e a Hospital Universitario de Canarias, Department of Cardiology, Tenerife, Spain b Facultad de Ciencias de la Salud, Universidad Europea de Canarias, Tenerife, Spain c Instituto Universitario de Tecnologias Biomedicas, Tenerife, Spain d University of La Laguna, Department of Physiology, Tenerife, Spain e Hospital Central de Asturias, Department of Cardiology, Oviedo, Spain

PURPOSE We investigated whether anaerobic threshold (AT) and ventilatory efficiency (minute ventilation/carbon dioxide production slope, VE/VCO2 slope), both significantly associated with mortality, can be predicted by questionnaire scores and/or other laboratory measurements. METHODS Anaerobic threshold and VE/VCO(2) slope, plasma N-terminal pro-brain natriuretic peptide (NT-proBNP), and the echocardiographic markers left ventricular ejection fraction (LVEF) and left atrial (LA) diameter were measured in 62 patients with heart failure (HF), who also completed the Minnesota Living with Heart Failure Questionnaire (MLHF), and the Specific Activity Questionnaire (SAQ). Linear regression models, adjusting for age and gender, were fitted. RESULTS While the etiology of HF, SAQ score, MLHF score, LVEF, LA diameter, and logNT-proBNP were each significantly predictive of both AT and VE/VCO2 slope on stepwise multiple linear regression, only SAQ score (P < .001) and logNT-proBNP (P = .001) were significantly predictive of AT, explaining 56% of the variability (adjusted R(2) = 0.525), while logNT-proBNP (P < .001) and etiology of HF (P = .003) were significantly predictive of VE/VCO(2) slope, explaining 49% of the variability (adjusted R(2) = 0.45). The area under the ROC curve for NT-proBNP to identify patients with a VE/VCO(2) slope greater than 34 and AT less than 11 mL · kg(-1) · min(-1) was 0.797; P < .001 and 0.712; P = .044, respectively. A plasma concentration greater than 429.5 pg/mL (sensitivity: 78%; specificity: 70%) and greater than 674.5 pg/mL (sensitivity: 77.8%; specificity: 65%) identified a VE/VCO(2) slope greater than 34 and AT lower than 11 mL · kg(-1) · min(-1), respectively. CONCLUSIONS NT-proBNP is independently related to both AT and VE/VCO(2) slope. Specific Activity Questionnaire score is independently related only to AT and the etiology of HF only to VE/VCO(2) slope.

Incremental exercise testing to a symptom-limited maximum has been used to measure the ratio of the increase in ventilation (V.E) to the increase in CO(2) output (V.CO(2)) during exercise (V.E/V.CO(2) slope), a valuable index reflecting the severity of the ventilation-perfusion mismatch in heart failure. Here we studied whether this same value for the slope of V.E/V.CO(2) could be determined from a short constant work-rate exercise test of moderate intensity. Twenty-three patients with a previous myocardial infarction underwent moderate-intensity (69+/-15 W) constant work-rate exercise for 6 min and an incremental work-rate exercise test to the max. The V.E/V.CO(2) slope was calculated from the incremental exercise test from the start of increasing the work-rate to the ventilatory compensation point. The V.E/V.CO(2) slope was similarly calculated from the start of constant work-rate exercise until the 4th minute, when V.E and V.CO(2) changed minimally. The V.E/V.CO(2) slope determined from incremental exercise was 33.8+/-5.9, ranging from 20.9 to 42.8. The slope obtained from constant work-rate exercise was 32.9+/-5.7. The V.E/V.CO(2) slopes obtained from the two exercise tests did not differ significantly. The slope obtained from constant work-rate exercise was significantly positively correlated with the slope obtained from the incremental exercise (r=0.84, p

Exercise testing with ventilatory expired gas analysis has proven to be a valuable tool for assessing patients with heart failure (HF). Peak oxygen consumption (peak VO2) continues to be considered the gold standard for assessing prognosis in HF. The minute ventilation--carbon dioxide production relationship (VE/VCO2 slope) has recently demonstrated prognostic significance in patients with HF, and in some studies, it has outperformed peak VO2.Two hundred thirteen subjects, in whom HF was diagnosed, underwent exercise testing between April 1, 1993, and October 19, 2001. The ability of peak VO2 and VE/VCO2 slope to predict cardiac-related mortality and hospitalization was examined.Peak VO2 and VE/VCO2 slope were demonstrated with univariate Cox regression analysis both to be significant predictors of cardiac-related mortality and hospitalization (P.01). Multivariate analysis revealed that peak VO2 added additional value to the VE/VCO(2) slope in predicting cardiac-related hospitalization, but not cardiac mortality. The VE/VCO2 slope was demonstrated with receiver operating characteristic curve analysis to be significantly better than peak VO2 in predicting cardiac-related mortality (P.05). Although area under the receiver operating characteristic curve for the VE/VCO2 slope was greater than peak VO2 in predicting cardiac-related hospitalization (0.77 vs 0.73), the difference was not statistically significant (P =.14).These results add to the present body of knowledge supporting the use of cardiopulmonary exercise testing in HF. Consideration should be given to revising clinical guidelines to reflect the prognostic importance of the VE/VCO2 slope in addition to peak VO2.

The minute ventilation-carbon dioxide production (VE/VCO2) slope, obtained during exercise testing, possesses prognostic value in heart failure (HF). The VE-VCO2 relationship is generally linear thereby hypothetically producing similar slope values regardless of the exercise-test time interval used for calculation.This study assesses the ability of the VE/VCO2 slope, calculated at different time intervals throughout a progressive exercise test, to predict 1-year cardiac-related hospitalization and mortality in subjects with HF.Seventy-two subjects underwent symptom-limited exercise testing with ventilatory expired gas analysis. Mean age and left ventricular ejection fraction for 44 male and 28 female subjects were 51.2 years (+/-13.0) and 27.0% (+/-12.3) respectively. The VE/VCO2 slope was calculated from time 0 to 25, 50, 75 and 100% of exercise time and subsequently used to create five randomly selected VE/VCO2 slope categories.(The intraclass correlation coefficient found calculation of the VE/VCO2 slope, when divided into quartiles, to be a reliable measure (alpha=0.94, P0.0001). Univariate Cox regression analysis revealed all VE/VCO2 slope categories (25-100% and random selections) were significant predictors of cardiac-related hospitalization and mortality over a 1-year period. Multivariate Cox regression analysis revealed all VE/VCO2 slope categories outperformed peak oxygen consumption (VO2) in predicting hospitalization and mortality at 1 year.Although the different classification schemes were not identical, these results suggest VE/VCO2 slope maintains prognostic significance regardless of exercise-test time interval. Calculation of VE/VCO2 slope may therefore still be valuable in subjects putting forth a sub-maximal effort while effort-dependent measures, such as peak VO2, are not.

This study aimed to determine the relation between the regression slope relating minute ventilation to carbon dioxide output (V˙E/V˙CO2 slope) and maximum phonation time (MPT), and the MPT required to attain a threshold value for V˙E/V˙CO2 slope of ≤34 in chronic heart failure (CHF) patients. This cross-sectional study enrolled 115 CHF patients (mean age, 54.5 years; men, 84.9%). V˙E/V˙CO2 slope was assessed during cardiopulmonary exercise testing (CPX). Thereafter, patients were divided into 2 groups according to exercise capacity: V˙E/V˙CO2 slope ≤34 (V˙E/V˙CO2 ≤34 group, n = 81) and V˙E/V˙CO2 slope >34 (V˙E/V˙CO2 >34 group, n = 34). For MPT measurements, all patients produced a sustained vowel/a:/ for as long as possible during respiratory effort from the seated position. All subjects showed significant negative correlation between V˙E/V˙CO2 slope and MPT (r = −0.51, P 34 group (21.4 ± 6.4 vs 17.4 ± 4.3 s, F = 7.4, P = 0.007). The appropriate MPT cut-off value for identifying a V˙E/V˙CO2 slope ≤34 was 18.12 seconds. An MPT value of 18.12 seconds may be a useful target value for identifying CHF patients with a V˙E/V˙CO2 slope ≤34 and for risk management in these patients.