['Diastolic dysfunction is important in the pathophysiology of heart failure with preserved ejection fraction (HFpEF). Sympathetic nervous hyperactivity may contribute to the development of diastolic dysfunction. The aim of this study was to determine the relationship between myocardial sympathetic innervation quantified by ', 'Forty-one HFpEF patients having an echocardiographic left ventricular ejection fraction ≥ 40% and 12 age-matched volunteers without heart failure underwent the echocardiographic examination and ', 'Grade 2 to 3 diastolic dysfunction (DD'] Is impaired Myocardial Sympathetic Innervation Associated with Diastolic Dysfunction in Patients with Heart Failure with Preserved Ejection Fraction : 11C-hydroxyephedrine PET Study?