The primary objective of this study was to determine if higher adherence to a Mediterranean diet pattern is associated with a lowered severity of HF, indicated by reduced cardiac decompensations in the previous 12 months, a better functional class according to the New York Heart Association (NYHA) scale, higher perceived quality of life according to the Spanish version of the Kansas City Cardiomyopathy Questionnaire (KCCQ), and lower plasma concentrations of congestive biomarkers (NTproBNP and CA125) compared to low adherence to a Mediterranean diet. Here, NPPB is linked to hydrops fetalis.