This finding may indicate a reduction in cardiac NPY release in severely dilated hearts and/or an overall reduction in innervation, supported by the risk imparted by a reduced heart to mediastinal ratio and iobenguane washout in the ADMIRE-HF study.21 Coronary sinus NPY levels were also associated with the 6-minute walk test, a prognostic factor in patients with HF, and with N-terminal–pro hormone brain natriuretic peptide levels, a marker of HF symptoms22 and risk of HF hospitalization.23 The gene discussed is NPY; the disease is hydrops fetalis.