Abstract
BACKGROUND: Autonomic neuropathy assessment is needed for the diagnosis and prognostication of different clinical disorders. Heart rate variability (HRV) and autonomic reactivity assessment by Ewing's battery of tests form the cornerstones of laboratory assessment of cardiac autonomic neuropathy evaluation. PURPOSE: While these tests are routinely used, there are conflicting reports regarding the visit-to-visit repeatability of these tests. Therefore, we assessed autonomic measures derived using aforementioned tests on multiple visits in healthy subjects. METHODS: We enrolled 31 healthy subjects and performed autonomic function evaluation on five visits by assessment of HRV and autonomic reactivity on day 1 forenoon and afternoon, next day, one week later and one month later. Repeatability assessment was evaluated using Intraclass correlation coefficients. Values were defined as moderate, good and excellent based on previously reported criteria. RESULTS: Thirty-one subjects completed all five visits (17 males, 14 females; mean age = 29 ± 5.44 years). While time-domain measures demonstrated good to excellent repeatability, frequency-domain measures were only moderately repeatable. Autonomic reactivity indices also displayed good to excellent repeatability with the exception of blood pressure response to orthostatic challenge which was moderately repeatable. CONCLUSION: We recommend that sole reliance on frequency domain metrics for HRV assessment should be avoided. HRV indices and autonomic reactivity measures may continue to be used for cardiac autonomic neuropathy assessment.