Melatonin might lower serum NT‐Pro BNP and improve disease‐specific health‐related quality of life in patients with HFrEF. Thus, it could be a valuable supplement for these patients. Further studies in subgroups of patients with HF, such as diabetic or hypertensive cardiomyopathic patients, and sensitive evaluation methods for cardiac function might provide new information in this regard. The gene discussed is NPPB; the disease is hydrops fetalis.