Objectives: To describe demographic features,assessment, management and outcomes of patients who were diagnosed with heart failure after presenting to an emergency department (ED) with a principal symptom of dyspnoea. Design: Planned substudy of the prospective, descriptive cohort study: Asia, Australia and New Zealand Dyspnoea in Emergency Departments (AANZDEM). Setting: 46 EDs in Australia, New Zealand, Singapore, Hong Kong and Malaysia collected data over 3 72-hour periods in May, August and October 2014. Participants: Patients with an ED diagnosis of heart failure. Outcome measures: Outcomes included patient epidemiology, investigations ordered, treatment modalities used and patient outcomes (hospital length of stay (LOS) and mortality). Results: 455 (14.9%) of the 3044 patients had an ED diagnosis of heart failure. Median age was 79 years, half were male and 62% arrived via ambulance. 392 (86%) patients were admitted to hospital. ED diagnosis was concordant with hospital discharge diagnosis in 81% of cases. Median hospital LOS was 6 days (IQR 4-9) and in-hospital mortality was 5.1%. Natriuretic peptide levels were ordered in 19%, with lung ultrasound (<1%) and echocardiography (2%) uncommonly performed. Treatment modalities included non-invasive ventilation (12%), diuretics (73%), nitrates (25%), antibiotics (16%), inhaled â-agonists (13%) and corticosteroids (6%). Conclusions: In the Asia Pacific region, heart failure is a common diagnosis among patients presenting to the ED with a principal symptom of dyspnoea. Admission rates were high and ED diagnostic accuracy was good. Despite the seemingly suboptimal adherence to investigation and treatment guidelines, patient outcomes were favourable compared with other registries.