Decreased myocardial flow reserve (MFR) is associated with diastolic dysfunction (DD), increased estimated left ventricular (LV) filling pressure, and abnormal left atrial (LA) strain in patients with normal ejection fraction, normal perfusion on positron emission tomography (PET) imaging, and risk factors for heart failure with preserved ejection fraction (HFpEF). This according to a retrospective study of patients with a history of HF who underwent clinically induced rest/stress cardiac rubidium-82 PET imaging and transthoracic echocardiography within 90 days. Global MFR was calculated as the ratio of stress to rest myocardial blood flow. Researchers found:

• 73 patients (age 64 ±11 years, 52% male) were identified with no epicardial perfusion defect on cardiac PET and an ejection fraction ≥50%.
• Decreased MFR is associated with LV DD.
• MFR is associated with LA strain independent of age, gender, body mass index, hypertension, chronic kidney disease, diabetes, and CAD status.
• MFR is related to comorbidity burden in individuals at risk of HFpEF.