The aldosterone receptor antagonists (ARAs) spironolactone (Aldactone) and eplerenone (Inspra) have become part of standard medical therapy for heart failure, having shown clinical efficacy in randomized trials in patients with advanced symptomatic systolic heart failure, postinfarction heart failure with cardiac dysfunction, and systolic heart failure with mild symptoms. The benefits include a lower rate of death. Yet to be answered is whether the two drugs are clinically equivalent; another question is whether they may benefit everyone with symptomatic heart failure, including diastolic heart failure.