1. Symptoms and/or signs of heart failure
   • Typical symptoms: exertional dyspnea, fatigue, orthopnea, paroxysmal nocturnal dyspnea, edema.
   • Signs may include raised JVP, pulmonary crackles, peripheral edema, or congestion.
2. Preserved LV systolic function
   • LVEF ≥50%.
3. Objective evidence of raised LV filling pressures or cardiac structural/functional abnormality Evidence may be obtained from one or more of:
   • Natriuretic peptides: raised BNP or NT-proBNP, recognizing that obesity may suppress levels and atrial fibrillation raises them.
   • Resting echocardiography: evidence supporting elevated filling pressure or diastolic dysfunction, such as elevated E/e′, left-atrial enlargement, increased LV mass/concentric remodeling, or elevated pulmonary artery systolic pressure.
   • Invasive hemodynamics: elevated pulmonary capillary wedge pressure (PCWP) or LV end-diastolic pressure. A PCWP ≥15 mmHg at rest or ≥25 mmHg with exercise supports HFpEF.
   • If resting testing is non-diagnostic but suspicion remains high, use diastolic stress echocardiography or exercise right-heart catheterization.
4. No alternative explanation that better accounts for symptoms Exclude or address mimics such as chronic lung disease, anemia, obesity/deconditioning, renal or liver disease, venous insufficiency, and primary valvular, pericardial, infiltrative, or hypertrophic cardiomyopathy.

Useful diagnostic algorithms

• HFA-PEFF algorithm: Pretest assessment, Echo plus natriuretic peptide scoring, Functional testing, Final etiologic work-up. A score ≥5 supports definite HFpEF; 2-4 is indeterminate and warrants stress or invasive testing; ≤1 makes it unlikely.
• H₂FPEF score: obesity, use of ≥2 antihypertensives, atrial fibrillation, pulmonary hypertension, age >60 years, and elevated E/e′. It estimates probability rather than independently proving the diagnosis.