Heart failure medications save lives.
Over 36 months,
NNT for ACEi/ARB is 26;
NNT for beta-blocker is 9;
NNT for mineralocorticoid receptor antagonists is 6.
Dosages are important though, and many patients may not be on sufficient dosages.
Here are a number of tables useful for references, adapted from ACC/AHA guidelines 2013.