Ubiquinol Treatment in Patients With Heart Failure and Preserved Ejection Fraction

Inclusion Criteria: * Typical signs and symptoms of congestive heart failure (CHF) (New York Association Class 2-4). * Normal ejection fraction on echocardiography (EF ≥50%). * Evidence of diastolic dysfunction on non-invasive imaging (E:e' \> 15 or e:e' \> 8 with other measures of diastolic dysfunction such as e/a \< 0.5 with elevated deceleration time or left atrial volume index \> 40 cc/m2 or presence of elevated left ventricular mass index or elevated pulmonary pressures). * Stable medical therapy for 4 weeks prior to randomization Exclusion Criteria: * Chronic atrial fibrillation. * Acute coronary syndrome or coronary revascularization within 60 days. * Clinically significant valvular disease. * Known infiltrative cardiomyopathy (e.g. amyloidosis), hypertrophic cardiomyopathy or chronic pericardial disease. * Inability/refusal to provide informed consent