This document discusses acute decompensated heart failure (ADHF), which refers to new or worsening signs and symptoms of heart failure requiring medical care or hospitalization. ADHF accounts for over 50% of heart failure costs in the US. It has a high mortality and readmission rate. The document outlines common causes and presentations of ADHF and emphasizes the importance of a thorough clinical evaluation to diagnose ADHF and distinguish it from other potential causes of symptoms like shortness of breath. It describes assessing signs of congestion and hypoperfusion to classify patients and guide initial treatment.