We evaluated if a 1-month treatment with IVA ( 5 mg b.i.d. ) or - blockers ( carvedilol 6.25 mg b.i.d. or bisoprolol 1.25 mg b.i.d. ) improves the QOL ( assessed by SF-36 questionnaire ) in patients with CHF with reduced left ventricular ejection fraction ( < 50 % ) .