In 2007, the Heart Failure and Cardiac Ultrasound Group of the European Society of Cardiology (ESC) renamed this type of heart failure as heart failure with normal left ventricular ejection fraction (HFNEF) and published an expert consensus on the diagnosis of this disease in the European Heart Journal (Eur Heart J 2007, 28(20):2539). (Eur Heart J 2007, 28(20):2539) and published an expert consensus on the diagnosis of this disease. Currently, most physicians are far less aware of HFNEF than of systolic insufficiency (reduced ejection fraction) heart failure. There are still many unanswered questions about the pathogenesis and even the diagnosis of HFNEF that need to be explored. 1, HFNEF concept HFNEF often refers to diastolic heart failure (DHF), caused by slow left ventricular relaxation and left ventricular stiffness leading to diastolic insufficiency. However, HFNEF is not exactly equivalent to DHF, it is also seen in systolic heart failure (SHF). patients with HFNEF retain overall left ventricular systolic function but still have reduced myocardial tissue Doppler velocity, and this reduction indicates some degree of impaired systolic function. In the absence of a precise distinction between LV diastolic and systolic insufficiency, it is recommended that heart failure without reduced LVEF be referred to as HFNEF or heart failure with surviving LV ejection function in both clinical diagnosis and clinical studies, rather than DHF. 2. HFNEF diagnosis: expert consensus More than half of heart failure patients with LVEF ≥50% exhibit HFNEF and are mostly elderly, female, and HFNEF is similar to SHF, with considerable morbidity and mortality (1-year mortality >20%), and the prevalence is increasing. The diagnosis of HFNEF is more complex, and in 2007 the ESC expert consensus updated the diagnostic criteria for the disease (Figure 1). At the core, 3 conditions need to be met: signs or symptoms of heart failure: manifestation of dyspnea alone may also be clinical evidence of HFNEF. Normal or mildly abnormal left ventricular systolic function: LVEF > 50%, left ventricular end-diastolic volume index (LVEDVI)