**2. Types of HF**

Traditionally, HF has been divided into three phenotypes based on the measurement of left ventricular ejection fraction (LVEF). Reduced LVEF is defined as ≦40%, and left ventricular systolic dysfunction. This is designated as heart failure with reduced ejection fraction (HFrEF). Mildly reduced LVEF is defined as between 41% and 49%. Clinical features and prognosis have not yet been fully characterized. This is designated as heart failure with mildly reduced ejection fraction (HFmrEF). Those with symptoms and signs of HF, with evidence of structural and/or functional cardiac abnormalities and/or raised natriuretic peptides (NPs), and with an LVEF ≥ 50%, have heart failure with preserved ejection fraction (HFpEF). No effective treatments have been established. The simplest terminology used to describe the severity of HF is the New York Heart Association (NYHA) functional classification.

The etiology of HF varies according to geography. In western countries and developed countries, coronary artery disease and hypertension are predominant factors. With regard to ischemic etiology, HFmrEF resembles HFrEF, with a higher frequency of underlying CAD compared to those with HFpEF. **Table 1** shows the definition of HF based on LVEF [1].

The simplest terminology used to describe the severity of HF is the New York Heart Association (NYHA) functional classification. The NYHA functional classification was developed by the New York Heart Association as a system to classify patients with heart diseases according to the severity of symptoms resulting from physical


*HF, heart failure; LV, left ventricular; LVEF, left ventricular ejection fraction.*

#### **Table 1.**

*Definition of HF with reduced ejection fraction, mildly reduced ejection fraction, and preserved ejection fraction.*

*A Home-Based Heart Failure Nursing Intervention Supporting Self-Management and Lives DOI: http://dx.doi.org/10.5772/intechopen.102509*

activity and has been used in the severity classification of HF. NYHA class II patients were further classified into those with slight limitation of physical activity (IIs) and those with moderate limitation of physical activity (IIm).

NYHA I is "No limitation of physical activity. Ordinary physical activity does not cause severe fatigue, palpitations, dyspnea or angina."

NYHA II is "Slight or moderate limitation of physical activity. Comfortable at rest, but ordinary physical activity causes fatigue, palpitations, dyspnea or angina."

NYHA III is "Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, palpitations, dyspnea or angina."

NYHA IV is "Unable to carry on any physical activity without symptoms of HF, or symptoms of HF and angina at rest. Even slight activity worsens symptoms."
