Diastolic heart disease is common and appears to be the primary abnormality in a substantial proportion of all patients with CHF. The epidemiology and natural history of the condition appears different to that of systolic heart failure, resulting in significant morbidity although contributing little to overall mortality. Clinical assessment alone is inadequate to distinguish systolic from diastolic failure, and echocardiography is an essential investigation in the management of these patients. From a therapeutic standpoint an alternative approach to treatment is likely to be indicated, and the results of recent major trials in systolic heart failure cannot necessarily be extrapolated to this group of patients.