Inclusion Criteria:  >18 yrs LVEF ≥ 50% (on last assessment, <2 years)  Diagnosis of HFpEF or Shortness of breath with NYHA Class ≥ 2 and one of the following:  pulmonary edema on chest imaging or documented on exam or on loop diuretics NTproBNP >400 ng/ml in the last 24 months HFpEF>50% hospitalization in the last 3 years Qualitative echo: > mild diastolic dysfunction on echo report and > mild left ventricular hypertrophy and left atrial dilation or quantitative echo: left ventricular hypertrophy [men ≥115 g/m², women ≥95 g/m² or relative wall thickness >0.42 or any LV wall thickness >1.2cm and has LA dilation (>28ml/m2)  Exclusion Criteria:  <18yo resting heart rate >100/min patients with LVEF <50% advanced end-stage heart failure, symptomatic COPD on home O2, uncontrolled severe HTN (SBP >160/100 mmHg) patients with life expectancy <6 months, end-stage liver cirrhosis, more than moderate valve disease, infiltrative myocardial disease constrictive pericarditis or myocarditis, patients unable to participate in follow up, pregnant patients or patients without reliable contraceptive agent for the duration of study participation), left ventricular outflow tract obstruction, bleeding dyscrasias, blood dyscrasias, Patients on oral ketoconazole, itraconazole, fluconazole, miconazole, fluvoxamine, fluoxetine, nefazodone, sertraline, erythromycin, clarithromycin or azithromycin