When comparing all clinical characteristics assessed in this study, significant differences between group 1 (stage 0 + 1) and group 2 (stage 2) could only be evidenced for STS score (higher values in group 2, p = 0.016), heart rhythm (sinus rhythm versus atrial fibrillation, higher frequency of atrial fibrillation in group 2, p < 0.001, Figure 2a), 6-minutes’ walk test (6MWT) (lower distances in group 2, p = 0.014, Figure 2b), Brain natriuretic peptide (BNP) serum levels (higher values in group 2, p = 0.016, Figure 2c) and ≥ II° mitral regurgitation (higher frequency in group 2, p = 0.006). Here, NPPB is linked to atrial fibrillation.