Introduction: 6-minute walk test (6MWT) is a simple exercise tool commonly used for functional assessment of exercise capacity in Pulmonary Arterial Hypertension (PAH). However, current risk stratification scores for PAH provide just assessment of 6-minute walking distance as a parameter related to survival. Aim: Evaluate the relationship between survival and chronotropic response during the 6MWT at time of diagnosis and after 6 months (6-m) and 1 year (1-y) from the start of a PAH therapeutic regimen. Methods: a 60 monocentric cohort of PAH WHO group 1 patients (pts) was retrospective analyzed. Categorical measures were summarized as frequencies and percentages. Mann-Whitney test was used to assess the correlation between heart rate (HR) peak and survival at baseline and during 6-m and 1-y follow-up. Results: 13 pts were excluded (3 lost in follow-up and 10 for insufficient data), leaving 47 pts as the final sample for statistical analysis. 19 of them died (40.4%) and 2 underwent lung transplant (4.3%). Mann-Whitney test gave a p-value = 0.022, indicating a significant difference in maximal HR at peak of exercise between the deceased and surviving patients, with a mean respectively of 112±18 bpm and 124±19 bpm. At 6-m and 1-y analysis such correlation was not found, due to different treatment regimens. Conclusions: Assessment of chronotropic response at time of diagnosis could acquire a role in long-term prognostic stratification in PAH. Our study confirms the non indication of ?-blockers use in treatment regimen of PAH because of their negative chronotropic activity.