The efficacy and safety of levosimendan administration in patients with acute heart failure admitted to intensive care units has been well established. However, no information is available on the drug's beneficial effects in emergency departments. We studied 40 patients with acute heart failure who showed no or only partial improvement after conventional treatment and who received levosimendan during the period 2005-2006. The patients' mean age was 76 (9) years. The most common etiology was ischemic heart disease, and 85% of patients were in New York Heart Association (NYHA) class III or IV. The clinical response was favorable in 82% of patients, while adverse effects occurred in 18%. Some 70% were admitted to the emergency department short-stay unit. These findings indicate that levosimendan can be used safely and effectively in hospital emergency departments.