Dual antagonist of AT1 receptors for angiotensin II and neprilysin, with the generic name sacubitril valsartan (formaly LCZ 696 or angiotensin receptor blocker and neprilysin inhibitor-ARNI) was clinically tested in the treatment of hypertension and heart failure. The mechanism of action is in the blockade of AT1 receptors by valsartan in combination with the inhibition of natriuretic peptides degradation, which leads to increased vasodilatation. The first clinical trial PARAMOUNT with LCZ696 in the treatment of heart failure patients with preserved ejection fraction has shown a significant decrease of NT-proBNP concentrations. Clinical trial PARADIGM-HF in patients with decreased ejection fraction and high natriuretic peptides levels was finished prematurely for a positive effect of LCZ696 as compared with enalapril. Cardiovascular mortality decreased by 20% and first hospitalisation for heart failure by 21%. The PARAGON-HF study is testing the effect of these drugs in patients with preserved ejection fraction. We show a summary of information supporting and questioning the suggestion that ARNI could replace ACE inhibitors in the treatment of heart failure.