Giane A. R. Samora

Reference equations for the six-minute walk distance based on a Brazilian multicenter study

Background It is important to include large sample sizes and different factors that influence the six-minute walking distance (6MWD) in order to propose reference equations for the six-minute walking test (6MWT). Objective To evaluate the influence of anthropometric, demographic, and physiologic variables on the 6MWD of healthy subjects from different regions of Brazil to establish a reference equation for the Brazilian population. Method In a multicenter study, 617 healthy subjects performed two 6MWTs and had their weight, height, and body mass index (BMI) measured, as well as their physiologic responses to the test. Delta heart rate (∆HR), perceived effort, and peripheral oxygen saturation were calculated by the difference between the respective values at the end of the test minus the baseline value. Results Walking distance averaged 586±106m, 54m greater in male compared to female subjects (p<0.001). No differences were observed among the 6MWD from different regions. The quadratic regression analysis considering only anthropometric and demographic data explained 46% of the variability in the 6MWT (p<0.001) and derived the equation: 6MWDpred=890.46-(6.11×age)+(0.0345×age2)+(48.87×gender)-(4.87×BMI). A second model of stepwise multiple regression including ∆HR explained 62% of the variability (p<0.0001) and derived the equation: 6MWDpred=356.658-(2.303×age)+(36.648×gender)+(1.704×height)+(1.365×∆HR). Conclusion The equations proposed in this study, especially the second one, seem adequate to accurately predict the 6MWD for Brazilians.

Capacidade funcional de indivíduos com insuficiência cardíaca avaliada pelo teste de esforço cardiopulmonar e classificação da New York Heart Association

The purpose of this study was to evaluate the capacity of the New York Heart Association (NYHA) classification to discriminate heart failure (HF) individuals classes II and III using cardiopulmonary exercise test (CPET) variables. Seventeen patients class II (age 44.47±10.11 years; ejection fraction 32.11±10.37%) and 15 class III (age 46.73±8.74 years; ejection fraction 30.46±10.23%) of NYHA participated in this study. They did a maximal CPET in a treadmill ergometer. According to the distribution of data, correlation of Pearson or Spearman was performed and, to compare the functional classes of NYHA, the Students t-test was used. Significant correlations (p<0.05) between oxygen consumption (VO2) and oxygen pulse (r=0.76), age (r=0.35) and body mass index (r=0.45) were found. There was no significant correlation between ventricular ejection fraction and the others studied variables. Comparing the functional classes of NYHA, significantly differences were found to VO2 and oxygen pulse (p<0.05). In this study, the correlations reflect the complexity in analyzing and understanding the process of disfunction in HF, once probably other factors influence each of the variables studied. The classification of NYHA was effective to differentiate the patients with HF, reinforcing the indication of this stratification to identify different groups of HF patients to scientific researches and therapeutic interventions.

Reprodutibilidade da determinação do limiar anaeróbico em pacientes com insuficiência cardíaca

BACKGROUND The anaerobic threshold (AT) provides information on functional capacity in heart failure (HF). However, the visual determination of the AT by ventilatory methods is subjective, being susceptible to differences between examiners. OBJECTIVE To evaluate the inter- and intra-examiner reproducibility in the determination of the AT in patients with mild to moderate HF, using visual-graphic and V-slope methods. To compare and correlate the results. METHODS After performing a cardiopulmonary exercise test on a treadmill, visual-graphic and V-slope methods were used for the analysis of the AT. To assess the reproducibility, three examiners determined the AT twice by each method, on different days. For statistical analysis, we used intra-class correlation coefficient (ICC) with p <0.05. RESULTS We evaluated a total of 16 subjects, with a mean age of 45.9 +/- 9.7 years, left ventricle ejection fraction of 20.5 +/- 8.1%, and peak exercise oxygen consumption of 20.6 +/- 7.8 mL/kgmin-1. The intra-examiner reproducibility was high in both methods for the three examiners, with ICC values between 0.87 and 0.99. The inter-examiner reproducibility was moderate in both visual-graphic method (ICC = 0.69) and V-slope method (ICC = 0.64). When comparing methods, the ICC found was 0.91. CONCLUSION AT determination by visual-graphic and V-slope methods showed high and moderate inter- and intra-examiner reproducibility, respectively. Moreover, both methods showed good agreement when compared with each other. These results suggest that both methods can be used in a reproducible way in AT assessment of patients with mild to moderate HF.

Cross-cultural adaptation and measurement properties of the Brazilian version of the Exercise Preference Questionnaire(stroke)

Highlights • The EPQ(stroke)-Brazil has adequate measurement properties.• The EPQ(stroke)-Brazil may assist in planning physical activities after stroke.• The EPQ(stroke)-Brazil indicates exercise preferences after stroke.• The EPQ(stroke)-Brazil has clinical utility and it is easy to use.