In this review, heart failure is confined to etiologies not due to rhythm disturbances or valvular heart disease. Besides measurement of natriuretic peptides, echocardiography is established as an important diagnostic procedure. Echocardiography is especially helpful in discriminating between heart failure with preserved ejection fraction (HF-PEF) and reduced ejection fraction (HF-REF). Because of its ease to be performed, the 6 min walk test continues to be a standard diagnostic procedure. Cardiopulmonary exercise testing provides more detailed information regarding differential diagnostic and prognostic considerations.