Acute Heart Failure is a heterogeneous set of syndromes associated with significant morbidity and mortality. There are several classifications of acute heart failure syndromes (AHFS) based on pathophysiology or clinical presentation. In the USA and in Europe, AHFS are the first cause of hospitalization of the elderly, and the leading health care cost. Despite this clinical and social importance, AHFS have received little attention from clinicians and researchers. Recently published epidemiological studies described clinical presentation, characteristics and treatment of over 100,000 patients hospitalized with AHFS. These studies also underlined the poor, short, and medium term prognosis, especially for the most severe patients admitted to an intensive care unit, with in-hospital mortality of 28%. Further epidemiological and clinical research is needed to improve our understanding of AHFS, thereby enhancing patient care.