Introduction:
Involvement of the cardiovascular autonomic nervous system in various diseases is often associated with increased morbidity and mortality.

Aim:
This study was aimed at determining the relationship between cardiovascular autonomic dysfunction (CAD) and echocardiographic indices of cardiac function in adult Nigerian sickle cell anaemia patients.

Material and methods:
A cross sectional study was done using 62 sickle cell anaemia patients and 62 age and sex matched normal controls. CAD was determined based on abnormal values in at least two of five non-invasive tests: Valsalva manoeuver, heart rate variation during deep breathing, heart rate response to standing, blood pressure response to sustained hand grip, and blood pressure response to standing. The subjects were subsequently evaluated with echocardiography.

Results and discussion:
Significant increases in left ventricular posterior wall thickness, left ventricular mass as well as left ventricular mass index were found in patients with CAD. Indices of left ventricular diastolic and systolic functions were comparable in patients with and without CAD, however patients with CAD had lower peak aortic systolic velocity (P = 0.038). Valsalva ratio correlated significantly with right ventricular internal diameter (r = –0.388; P = 0.009), left ventricular posterior wall diameter (r = –0.352; P = 0.019), left ventricular end systolic stress/end systolic dimension ratio (r = 0.512; P < 0.001), and pulmonary artery flow acceleration time (r = 0.499; P = 0.001).

Conclusions:
CAD is a serious complication of sickle cell anaemia. All the patients should be routinely evaluated for CAD.