Overall cardiac performance depends on both the systolic and diastolic function of the left ventricle (LV). Determinants of LV systolic function include preload, afterload, and contractility. In patients with congestive heart failure (CHF), abnormalities of systolic and diastolic function often coexist. In addition, compensatory changes that develop in response to low cardiac output and high ventricular pressures can affect the mechanical characteristics of the LV. Therapy of CHF is aimed at improving myocardial contractility and reducing both preload and afterload. Agents that can relieve volume overload and those that decrease intrinsic LV chamber stiffness (and increase compliance) will improve diastolic function.