CMR Assessment of Cardiac Microvascular Dysfunction in Patients With HFpEF

This study uses cardiac MRI (a detailed heart imaging technique) to evaluate microvascular dysfunction — tiny blood vessel problems inside the heart — in patients with heart failure with preserved ejection fraction (HFpEF), a type of heart failure where the heart pumps normally but is too stiff. Researchers want to understand how these small vessel abnormalities contribute to the condition. **You may be eligible if...** - You are 18 years or older - You have been diagnosed with HFpEF according to 2016 European heart failure guidelines (for the patient group) - You are able to provide written informed consent and safely undergo an MRI **You may NOT be eligible if...** - You are pregnant or breastfeeding - You have absolute contraindications to the MRI procedure (including poorly controlled asthma, severe kidney disease with GFR below 30, or atrial fibrillation) - You have had prior chemotherapy or radiation to the chest - You have known coronary artery disease, diabetes, or systemic inflammatory conditions - You are a control group participant with any known cardiac, lung, blood, or cancer condition Talk to your doctor to see if this trial is right for you.