[Heart or lung? : Diagnostics and management of unclear exertional dyspnea].

Exertional dyspnea is a nonspecific symptom with a variety of underlying causes. It can be challenging to differentiate a beginning cardiac disease from a pulmonary disease or from deconditioning alone. In the presence of obesity, the overall assessment is even more difficult. Rare diseases, such as pulmonary hypertension with dyspnea on exertion as the cardinal symptom are usually diagnosed late in the course of disease. The starting point of a successful evaluation is a thorough patient history. The combination of symptoms, clinical signs and findings leads to a preferred differential diagnosis. Readily available basic findings, such as physical examination, electrocardiogram (ECG), spirometry and laboratory tests help with the diagnosis. For unexplained causes, extended diagnostics such as echocardiography, blood gas analysis and finally special examinations are available. Cardiopulmonary exercise testing (CPET) and exercise echocardiography as well as right heart catheterization at rest and during exercise in the hands of experienced physicians allow an exact differentiation.