Deep Breathing, Valsalva, and Tilt Table Tests in Diabetics with and without Symptoms of Autonomic Neuropathy

Publisher Website
Google Scholar
Abstract
Autonomic neuropathy (AN) test results (Valsalva maneuver, deep breathing, and tilting) are frequently impaired in diabetics without symptoms of AN, particularly in those with peripheral neuropathy (PN). Twenty-four asymptomatic diabetics with PN, 17 diabetics with symptoms of AN and 24 healthy controls were studied. The heart rate reactions to the 3 tests were impaired in both patient groups. The Valsalva maneuver could not distinguish between the patient groups. The heart rate reaction to deep breathing, estimated as the expiration/inspiration (E/I) ratio, was slightly more disturbed in patients with AN than in those with PN (1.04 vs. 1.09, P < 0.05) but the frequency of abnormally low E/I ratios was high in both groups (76.5 vs. 54.2%, not significant). The immediate heart rate reaction to tilting, estimated as the brake index, clearly separated the patient groups. An abnormally low brake index was shown in 82.3% of AN patients and in 33.3% of PN patients (P < 0.01). The deep breathing test is sensitive for AN but an impaired immediate heart rate reaction to tilting is more specific for symptomatic AN.