 The study will be a single center, double-blind, randomized, parallel group trial enrolling a minimum of 80 patients designed to determine the efficacy of eplerenone in subjects with diastolic heart failure. Prior to administration of study medication, a medical history, physical exam, blood draw, electrocardiogram, 2D echocardiogram, and cardiomyopathy questionnaire will be performed. Subjects will then be randomized to receive either eplerenone 25 mg once daily or placebo for 2 weeks. At the Week 2 visit all patients will be titrated up to the next dose 50 mg eplerenone once daily or placebo. Each study arm will have 40 subjects who will participate for 9 months. Follow-up assessments will be completed at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 9 months. 