Cognitive functions of patients with decompensated heart (NYHA III-IV) failure are compared to age and gender matched patients with congestive heart failure (NYHA III-IV) without symptoms of cardiac decompensation and with healthy controls. Decompensated patients are tested before and after medical recompensation. For matched patients and controls, the pretest-posttest timing is based on the recompensation time of the respective patient with decompensated heart failure.