Study of cardiovascular autonomic insufficiency in advanced cancer patients.

To determine the incidence of cardiovascular autonomic insufficiency (CAI), 43 patients with advanced breast cancer and 20 normal controls were evaluated using electrocardiographic tests (heart rate variation during deep breathing and Valsalva maneuver and upon standing) and clinical tests (blood pressure variation during hand grip tests and upon standing). Nutritional status, tumor mass, Karnofsky performance status (PS) score (0-100), and peripheral reflexes were also determined. Tests for CAI were abnormal in 43 patients (52%), versus seven of 100 in 20 controls (7%, P less than 0.001). In cancer patients, tests for CAI were more frequently abnormal in patients with PS less than 60 (P less than 0.01), basal heart rate greater than 100 (P = 0.05), and malnutrition (P less than 0.01). We conclude that CAI is a frequent finding in patients with advanced breast cancer and should be suspected mainly in patients with a low PS, tachycardia, or malnutrition. It is probably a multifactorial syndrome, and malnutrition, drugs, decreased activity, or paraneoplastic syndromes are all possible causes for CAI.