How can entresto pills contribute towards the reduction in left ventricle ejection fraction from 0,5 to 0,35 as a result of the onset of atrial fibrillations?

Decreased EF from AF: Entreaties usually increases ejection fraction. In this instance, the most likely cause is the onset of atrial fibrillation causing a rapid and irregular heart rhythm. An additional factor is the loss of effective contraction of the upper chambers(atria) due to atrial fibrillation.

Low EF: Uncontrolled atrial fibrillation lowers left ventricular EF even further. Even with controlled a fib, the loss of atrial function causes a loss of EF by 12%. Entresto should help increase EF by its action of vasodilation which takes strain off the left ventricle.