Acute heart failure syndromes (AHFS) is a broad spectrum of heterogeneous conditions including pulmonary oedema, hypertensive crisis, worsening exacerbated CHF and cardiogenic shock. HF hospitalizations have steadily risen with more than one million in 2004 in the United States and a similar number has been reported in Europe. Each year heart failure accounts for 6.5 million days spent in hospital in the USA and 1.4 million days in France. Mortality data are derived from registries or clinical trials. Registry data in patients admitted to general or cardiology wards such as in Euroheart Failure Survey and ADHERE provide a far more optimistic picture compared with data from consecutive unselected patients in the most acute situation. such as in EFICA. Four-week mortality was higher than 25% in this case. A great pathophysiologic understanding of the different features of the various AHFS is needed in order to identify targets for therapy and research. This includes hemodynamics, the role of myocardial injury, neurohormonal and cytokine abnormalities and the cardiorenal syndromes. So far, very little progress has been made in developing new, effective therapies and implementing management guidelines in this patient population. Future clinical trial endpoints should be better designed and tailored to the various pathophysiological conditions of this complex syndrome. The goal of AHFS therapy is not only to prevent disease progression but also to have a beneficial effect on an acute event that exacerbates disease progression. A combined endpoint assessing survival and rehospitalisation rates is becoming increasingly popular for acute therapies. Specific trials may also need to be designed according to the time of access to the patient.