- Stable heart failure medications (ACEi, +/-beta blocker, +/-mineralocorticoid receptor antagonist) for the past 30 days (with the exception of diuretics) Females of childbearing potential must have a negative urine pregnancy test prior to randomization and agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to randomization, for the duration of study participation, and for 7 days following completion of therapy.