Over the last 20 years it has become evident that almost half the patients with clinical signs of heart failure do not have LVSD. This proportion is increasing 353 . Despite the prevalence of the latter group, there are far less diagnostic or intervention trials for this group, compared to those with LVSD. This distinction into two categories of heart failure have led to a classification system based on left ventricular ejection fraction. The Guideline Development Group (GDG) agreed on the following definitions: Heart failure with reduced ejection fraction (HFREF) This group of patients is characterised by heart failure with a left ventricular ejection fraction by echocardiography of less than 40%. Heart failure with preserved ejection fraction (HFPEF) This group of patients with heart failure have a left ventricular ejection fraction greater than 50%, o no alternative cause for the syndrome, o the presence of a non-dilated left ventricle; evidence of structural remodelling (left ventricular hypertrophy or dilated left atrium); or diastolic dysfunction through imaging o and have abnormal biomarkers. The GDG recognises that the two terms HFREF and HFPEF have several limitations. These include the variability of the left ventricular ejection fraction measured by different imaging modalities, and the lack of universal agreement on the threshold of ejection fraction at which these are defined or the exact definition of HFPEF. The GDG also recognised the proposal of another class as heart failure with mid-range ejection fraction (HFMREF). This proposal has not been fully clinically validated and remains the topic of further research 150, 354 . The GDG reviewed the available biomarkers for diagnosis of heart failure. Assays for both B-type natriuretic peptide (BNP) and NT-pro-BNP are commonly available. Other biomarkers have been identified but their utility is unclear. 