Recognizing the cardiac and non-cardiac origin of acute dyspnea is one of the most common situations encountered in the emergency department because of the atypical and interrelated clinical pictures in patients with several comorbidities. Acute dyspnea is responsible for the hospitalization of 2 to 4% of elderly subjects. The objective of our study is to evaluate the clinical judgment of the emergency physician, as to the etiological diagnosis of acute dyspnea to distinguish a cardiac cause from a non-cardiac cause.This is a prospective analytical study which took place over a period of eight months. Patients older than 18 years, who consulted the emergency room for acute dyspnea and for whom the etiological diagnosis (cardiac cause - non cardiac cause) remained uncertain after clinical and paraclinical investigations (ECG, chest X-ray, biological work-up) and this after a medical staff were included.