Patients with chronic heart failure are four times as likely as healthy individuals to have impaired thinking or "cognitive" abilities, according to a report in the Journal of Cardiac Failure.

Studies have shown a link between chronic heart failure and cognitive impairment in elderly patients, but little is known about the rate of cognitive impairment in the general population of patients with heart failure, according to Dr. Mary Jane Sauvé from the University of California, Davis, and her colleagues.

When patients with chronic heart failure were compared with healthy subjects of similar age, gender, and IQ, the patients scored significantly worse on most of the cognitive tests administered, the authors report.

The most frequent and severe impairments were in memory and learning, the researchers note.

The severity of cognitive impairment was not related to anxiety, depression, or level of heart function. However, a history of heart attack was associated with greater impairments on some tests.

"There is much to be learned about the circumstances favoring the development of cognitive impairment in these patients," the investigators write.