Cut-off values of 6-min walk test and sit-to-stand test for determining symptom burden in atrial fibrillation.

ABSTRACT

BACKGROUND: Since symptomatology is a major predictor of quality of life and an endpoint for the management of atrial fibrillation (AF), practical approaches for objectively interpreting symptom burden and functional impairment are needed. AIMS: We aimed to provide cut-off values for two frequently used field tests to be able to objectively interpret symptom burden in atrial fibrillation. METHODS: One hundred twenty-five patients with AF were evaluated with European Heart Rhythm Association (EHRA) score, 6-min walk test (6MWT), 30 s sit-to-stand test (30 s-STST), Short-Form 36 (SF-36), International Physical Activity Questionnaire-Short Form (IPAQ-SF), and spirometry. Patients with EHRA 1 were classified as "asymptomatic", and those with EHRA 2-4 as "symptomatic". Cut-off values of 6MWT and 30 s-STST for discriminating between these patients were calculated. RESULTS: The optimal cut-off value was "450 m" for 6MWT (sensitivity 0.71; specificity of 0.79) and "11 repetitions" for 30 s-STST (sensitivity 0.77; specificity of 0.70). Area under ROC curve was 0.75 for both tests (p < 0.001). Discriminative properties of the two tests were similar, and they were significantly correlated (r = 0.58; p < 0.001). Subgroup analysis revealed patients below cut-off values also had worse outcomes in SF-36, IPAQ-SF, and spirometry. CONCLUSIONS: In patients with AF, walking < 450 m in 6MWT or performing < 11 repetitions in 30 s-STST indicates increased symptom burden, as well as impaired exercise capacity, quality of life, physical activity participation, and pulmonary function. These cut-off values may help identifying patients who may require adjustments in their routine treatment or who may benefit from additional rehabilitative approaches.