This is a multi-center, observational study designed to evaluate the discriminative and prognostic value of pressure-volume (PV) loop analysis parameters and myocardial energetics derived from cardiac MRI in patients with heart failure with preserved ejection fraction (HFpEF). This study plans to enroll 3000 adult HFpEF patients and 500 adult healthy controls. The primary clinical endpoint was a composite of all-cause mortality and heart failure hospitalization, with events ascertained through medical records, clinic visits, and telephone follow-up. This study aims to determine whether cardiac MRI-derived PV loop analysis parameters and myocardial energetics provide incremental discriminative and prognostic information beyond conventional cardiac MRI parameters in patients with HFpEF. The study is non-interventional and does not involve any investigational drugs or devices.

Inclusion Criteria:

1. Symptoms and/or signs of HF ≥ New York Heart Association (NYHA) class II;
2. Left ventricular ejection fraction (LVEF) of 50% or higher;
3. N-terminal fragment of the prohormone of brain natriuretic peptide (NT-proBNP) level > 125 pg/mL or brain natriuretic peptide (BNP) level > 35 pg/mL in sinus rhythm, or NT-proBNP level > 365 pg/mL or BNP level > 105 pg/mL in atrial fibrillation;
4. At least one of objective indicators of (i) cardiac structural abnormalities including LA maximum volume index (LAVi max) > 29 mL/m2 or echocardiography-measured LV end-diastolic mass index (LVMi) ≥ 115 g/m2 for men and ≥ 95 g/m2 for women, and (ii) LV diastolic dysfunction including early and/or late diastolic mitral inflow velocity (E/A) < 1 or early diastolic mitral inflow velocity and/or mitral annular peak early diastolic velocity (E/e') > 13.

Exclusion Criteria:

1. Primary cardiomyopathy;
2. Acute coronary syndrome;
3. Primary severe valvular heart disease;
4. Acute pulmonary embolism;
5. Severe renal dysfunction;
6. Poor image quality that was insufficient to identify myocardial endocardium and epicardium.

Patients with heart failure with preserved ejection fraction experienced cardiac MRI scanning