The aim of this study was to determine how sacubitril/valsartan compared with valsartan in an outpatient setting affects left ventricular remodeling in heart failure with reduced ejection fraction and functional (or secondary) mitral regurgitation (SMR) due to the effect of dual inhibition of the renin-angiotensin system and neprilysin. Here, REN is linked to Mitral regurgitation.