Heart failure has become an increasingly important medical problem. It is one of the major reasons for hospitalization and is associated with increased mortality. The prevalence of heart failure is expected to rise with the aging of the population. About half of the patients with heart failure have preserved left ventricular systolic function, and heart failure in these patients is frequently ascribed to diastolic dysfunction. The common causes of diastolic dysfunction in the setting of preserved systolic function are listed in Table 16.1. A good understanding of the pathophysiology underlying heart failure in these patients should lead to a more reasoned approach to its management [1–5].