Heart rate variability and baroreflex sensitivity abnormalities in Guillain–Barré syndrome: a pilot study

Objective The current study aimed to investigate autonomic dysfunction in Guillain–Barré syndrome (GBS) patients and describe the results of computational heart rate variability (HRV)/baroreflex sensitivity (BRS) and autonomic challenge tests. Methods GBS patients were consecutively recruited and the results were compared to age- and gender-matched healthy controls. A series of autonomic function tests including computation-dependent tests (power spectrum analysis of HRV and BRS at rest) and challenge maneuvers (deep breathing, eyeball compression, active standing, the Valsalva maneuver, sustained handgrip, and the cold pressor test) were performed. Results Ten GBS patients (six men; mean age = 40.1 ± 13.9 years) and ten gender- and age-matched healthy controls were recruited. The mean GBS functional grading scale at disease plateau was 3.4 ± 1.0. No patients required intensive care unit admission or mechanical ventilation. Low-frequency HRV ( p = 0.027), high-frequency HRV ( p = 0.008), and the total power spectral density of HRV ( p = 0.015) were significantly reduced in patients compared to controls. The mean up slope ( p = 0.034), down slope ( p = 0.011), and total slope ( p = 0.024) BRS were significantly lower in GBS patients. The diastolic rise in blood pressure in the cold pressor test was significantly lower in GBS patients compared to controls ( p = 0.008). Interpretation Computation-dependent tests (HRV and BRS) were more useful for detecting autonomic dysfunction in GBS patients, whereas the cold pressor test was the only reliable challenge test, making it useful as a bedside measure of autonomic function in GBS patients.