Unrecognized cognitive impairment in cardiac rehabilitation patients.

To determine the prevalence of unrecognized brain dysfunction accompanying chronic severe cardiac disease, we examined 20 clinically stable consecutive admissions to a cardiac rehabilitation service who were free of known stroke or dementia. Age range was 47 to 85 years (mean +/- SEM, 72.5 +/- 2.1 years), the male: female ratio was 10:10. Multiple cognitive deficits including significant memory impairment and disorientation were present in eight patients (40%), and seven of these eight patients were unable to administer their own medications reliably. An additional six patients (30%) showed milder impairments. One patient was found to be normal after neurological examination, four showed evidence of a single brain lesion, and 15 of 20 (75%) had multiple neurological abnormalities suggesting multifocal brain disease. The mechanism of cognitive deficits in cardiac patients is unclear, and it may be related to multiple infarcts, or acute or chronic hypoxic damage secondary to arrhythmias, cardiac failure, or small vessel disease of the brain. The term "circulatory dementia" is proposed to describe patients with vascular disease and non-Alzheimer type dementia. Patients with cardiac disease should undergo cognitive screening, as early identification of patients at risk of progressive intellectual loss may allow early use of preventive therapy.