Abstract
The Korean Society of Heart Failure guidelines aim to provide physicians with evidence-based recommendations for diagnosing and managing patients with heart failure (HF). In Korea, the prevalence of HF has been rapidly increasing in the last 10 years. HF has recently been classified into HF with reduced ejection fraction (HFrEF), HF with mildly reduced ejection fraction (EF), and HF with preserved EF (HFpEF). Moreover, the availability of newer therapeutic agents has led to an increased emphasis on the appropriate diagnosis of HFpEF. Accordingly, this part of the guidelines will mainly cover the definition, epidemiology, and diagnosis of HF.