Inagaki T, et al. - Researchers evaluated the changes in heart rate and oxygen saturation (S_pO2) patterns during 6-min walk test (6MWT) in patients with chronic thromboembolic pulmonary hypertension. They noted a predominant association of the heart rate and S_pO2 change patterns during 6MWT with pulmonary hemodynamics in subjects with chronic thromboembolic pulmonary hypertension. During 6MWT, evaluating heart rate and S_pO2 change patterns could serve as a safe and convenient way to follow the change in pulmonary hemodynamics. Compared to subjects with mild chronic thromboembolic pulmonary hypertension, subjects with severe chronic thromboembolic pulmonary hypertension demonstrated significantly longer heart rate acceleration time, lower Δheart rate, and lower heart rate recovery during the first minute after 6MWT (HRR1).