The evidence of the benefits of pharmacological treatment in specific populations from subgroup analysis of the PARAGON-HF trial and (CHARM)-Preserved study [128] could encourage interventions targeting the NO-cGMP-PKG pathway and support future efforts to characterize and divide patients according to phenotype from an aetiologic perspective, which will allow tailored therapy with specific, well-defined patient cohorts to more precisely improve outcomes. This evidence concerns the gene PRKG1 and hydrops fetalis.