Cardiovascular autonomic neuropathy in HIV infected patients

Objective: To evaluate the presence and extent of autonomic dysfunction in HIV infected individuals of one ethnic group. Design: Prospective, age-sex matched study. Methods: 25 patients (seven asymptomatic (HIV), eight AIDS related complex (ARC), 10 AIDS) and 25 controls were recruited from patients and staff at the Aga Khan Hospital, Nairobi. Autonomic function was assessed by measurement of pulse rate variability on standing, rest, deep breathing, Valsalva manoeuvre, isometric exercise, cold face test, and mental stress. Blood pressure was measured during standing, supine resting, and on Valsalva manoeuvre. CD4 count was correlated with number of abnormal test results. Results: 21 patients had at least one abnormal test of autonomic function compared with one control (p<0.0001). There were significant differences between AIDS patients and controls for supine heart rate (p<0.001), Valsalva ratio (p=0.05), and cold face test (p=0.05), and almost significant results for mental stress (p=0.051). Evidence of autonomic hypersensitivity was found in response to exercise and/or mental stress in some patients with HIV or ARC. No difference was found in blood pressure measurements. Abnormalities in autonomic function occurred at all CD4 counts and all patients with four abnormal tests of heart rate variation had a CD4 count less than 300 x 10(6)/l. Conclusions: There is evidence of substantial autonomic dysfunction in AIDS patients compared with controls and mild abnormalities in the majority of HIV infected patients studied irrespective of CD4 count. Autonomic hypersensitivity may precede loss of function in some cases.