Abstract
OBJECTIVES: To document the degree of cognitive impairment in stable heart failure, and to determine its relation to the presence of Cheyne-Stokes respiration during sleep. SUBJECTS: 104 heart failure patients and 21 healthy normal volunteers. METHODS: Overnight oximetry was used (previously validated as a screening tool for Cheyne-Stokes respiration in heart failure). Cognitive function was assessed using a battery of neuropsychological tests. Left ventricular function was assessed by echocardiography. RESULTS: Heart failure patients performed worse than the healthy volunteers in tests that measured vigilance. Reaction times were 48% slower (0.89 (0.03) s v 0.60 (0.05) s p < 0.005) and they hit twice as many obstacles on the Steer Clear simulator (75 (6.4) v 33 (4.6); p < 0.005). Cognitive impairment within the heart failure group was unrelated to either the presence of Cheyne-Stokes respiration, the degree of left ventricular dysfunction, or indices of nocturnal oxygenation. CONCLUSIONS: Vigilance was impaired in heart failure but this did not appear to be related to the presence of Cheyne-Stokes respiration during sleep. Impaired vigilance as measured on the Steer Clear test has been associated with an increased risk of motor vehicle accidents. The issue of fitness to drive in heart failure requires further attention.