To the Editor.
—We were interested to read the review by Heinrich in the February 1982 Archives (142:339-344) and wish to add to his comments on autonomic insufficiency in patients receiving hemodialysis and patients with high spinal cord transection. In the former group there are a number of reports that subscribe to abnormal cardiovascular responses to autonomic testing.1-3 Closer analysis, however, indicates that in the majority of these studies only a few tests of autonomic function had been performed, often with inadequately matched controls. This makes interpretation difficult, if not impossible. We have completed a detailed study, using physiological, pharmacological, and biochemical approaches aimed at assessing cardiovascular aspects of autonomic function in patients with chronic renal failure undergoing maintenance hemodialysis. Some of these patients had regularly suffered from hemodialysis-induced hypotension. Comparisons were made with a matched group of normal subjects who were studied in a similar manner. The responses