BACKGROUNDThe 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.OBJECTIVETo 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.METHODSAfter 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.RESULTSWe 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.CONCLUSIONAT 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.

FUNDAMENTO: O limiar anaeróbico (LA) fornece informações sobre a capacidade funcional na insuficiência cardíaca (IC). Porém, a determinação visual do LA por métodos ventilatórios é subjetiva, ficando suscetível à diferença entre examinadores. OBJETIVOS: Avaliar a reprodutibilidade intraexaminador e interexaminadores na determinação do LA em indivíduos com IC leve a moderada pelos métodos visual-gráfico e V-slope. Comparar e correlacionar os resultados encontrados. MÉTODOS: Após realização de teste ergoespirométrico em esteira, utilizaram-se os métodos visual-gráfico e V-slope para análise do LA. Para avaliar a reprodutibilidade, três examinadores detectaram o LA duas vezes em cada método, em dias distintos. Para análise estatística, utilizou-se coeficiente de correlação intraclasse (CCI) com p < 0,05. RESULTADOS: Foram avaliados 16 indivíduos com média de idade de 45,9 ± 9,7 anos, fração de ejeção do ventrículo esquerdo de 20,5 ± 8,1% e consumo de oxigênio no pico do esforço de 20,6 ± 7,8 ml/kg•min-1. A reprodutibilidade intraexaminador foi alta nos dois métodos para os três examinadores, com valores de CCI entre 0,87 e 0,99. A reprodutibilidade interexaminadores foi moderada tanto no método visual-gráfico (CCI = 0,69) quanto no V-slope (CCI = 0,64). Quando se contrastaram os métodos, foi encontrado CCI de 0,91. CONCLUSÕES: A detecção do LA por meio dos métodos visual-gráfico e V-slope apresentou reprodutibilidade intraexaminador e interexaminadores alta e moderada, respectivamente. Além disso, os dois métodos demonstraram alta concordância quando contrastados. Esses resultados sugerem que ambos os métodos podem ser utilizados, de forma reprodutível, na avaliação do LA em indivíduos com IC de leve a moderadaBACKGROUND: 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/kg•min-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.