ACE and hydrops fetalis: In PARADIGM-HF (Prospective Comparison of ARNI with ACEI [ACE inhibitor] to Determine Impact on Global Mortality and Morbidity in Heart Failure; NCT01035255), a randomized, double-blind (DB), parallel-group study, the synergistic effects of RAAS and neprilysin inhibition (sacubitril/valsartan) versus RAAS inhibition alone (enalapril) led to significantly lower all-cause and cardiovascular mortality for HF with reduced ejection fraction (HFrEF) [8].