2013年美国心力衰竭管理指南(心衰指南)-英文

reasons for the development of HF. HF may be associated with a wide spectrum of LV functional abnormalities, which may range from patients with normal LV size and preserved EF to those with severe dilatation and/or markedly reduced EF. In most patients, abnormalities of systolic and diastolic dysfunction coexist, irrespective of EF. EF is considered important in classification of patients with HF because of differing patient

demographics, comorbid conditions, prognosis, and response to therapies (35) and because most clinical trials selected patients based on EF. EF values are dependent on the imaging technique used, method of analysis, and operator. Because other techniques may indicate abnormalities in systolic function among patients with a preserved EF, it is preferable to use the terms preserved or reduced EF over preserved or reduced systolic function. For the remainder of this guideline, we will consistently refer to HF with preserved EF and HF with reduced EF as HFpEF and HFrEF, respectively (Table 3).

2.1. HF With Reduced EF (HFrEF)

In approximately half of patients with HFrEF, variable degrees of LV enlargement may accompany HFrEF (36,

37). The definition of HFrEF has varied, with guidelines of left ventricular ejection fraction (LVEF) ≤35%, <40%, and ≤40% (18, 19, 38). Randomized clinical trials (RCTs) in patients with HF have mainly enrolled patients with HFrEF with an EF ≤35% or ≤40%, and it is only in these patients that efficacious therapies have been demonstrated to date. For the present guideline, HFrEF is defined as the clinical diagnosis of HF and EF ≤40%. Those with LV systolic dysfunction commonly have elements of diastolic dysfunction as well (39).

Although coronary artery disease (CAD) with antecedent myocardial infarction (MI) is a major cause of HFrEF, many other risk factors (Section 4.6) may lead to LV enlargement and HFrEF.

2.2. HF With Preserved EF (HFpEF)

In patients with clinical HF, studies estimate that the prevalence of HFpEF is approximately 50% (range 40% to 71%) (40). These estimates vary largely because of the differing EF cut-off criteria and challenges in diagnostic criteria for HFpEF. HFpEF has been variably classified as EF >40%, >45%, >50%, and ≥55%. Because some of these patients do not have entirely normal EF but also do not have major reduction in systolic function, the term preserved EF has been used. Patients with an EF in the range of 40% to 50% represent an intermediate group. These patients are often treated for underlying risk factors and comorbidities and with GDMT similar to that used in patients with HFrEF. Several criteria have been proposed to define the syndrome of HFpEF. These include (a) clinical signs or symptoms of HF; (b) evidence of preserved or normal LVEF; and (c) evidence of abnormal LV diastolic dysfunction that can be determined by Doppler echocardiography or cardiac

catheterization (41). The diagnosis of HFpEF is more challenging than the diagnosis of HFrEF because it is largely one of excluding other potential noncardiac causes of symptoms suggestive of HF. Studies have

suggested that the incidence of HFpEF is increasing and that a greater portion of patients hospitalized with HF have HFpEF (42). In the general population, patients with HFpEF are usually older women with a history of