Clinical heart failure with normal systolic function, usually assessed as the ejection fraction by echocardiography or nuclear techniques, is suggestive of diastolic dysfunction. The pathophysiology leading to diastolic heart failure is related to an increase in ventricular filling pressure relative to volume and secondary to either myocardial or pericardial disorders (Figure 1). Restrictive cardiomyopathy and constrictive pericarditis are two major pathophysiologic conditions characterized by diastolic heart failure. In both conditions, the ejection fraction can sometimes be reduced. This can occur because of marked restriction of filling leading to a small end-diastolic volume (reduced preload). Alternatively, true systolic dysfunction can occur in association with diastolic dysfunction, for example, in constrictive pericarditis with extension of the process involving the pericardium to the myocardium, and in hemochromatosis.