To the Editor,
We appreciate the precise review and insightful comments by our dear colleagues regarding our recent study entitled “Cardiovascular Autonomic Neuropathy in Rheumatoid Arthritis assessed by Cardiovascular Autonomic Function Tests: A cross-sectional survey” published in Anatol J Cardiol 2015; 15: 722-6.
In our study, we assessed cardiovascular autonomic neuropathy (CAN) in rheumatoid arthritis (RA) patients compared with control subjects by bedside autonomic function tests. Our study failed to show any statistically significant difference between cardiovascular autonomic function tests in RA patients and the control subjects (1).
Although in studies autonomic function tests are considered indices mainly of parasympathetic or sympathetic function, according to Ewing et al. (2), “The autonomic pathways involved in all cardiovascular reflex tests are however extremely complex and include both parasympathetic and sympathetic fibers to a greater or lesser extent. While heart rate responses are primarily mediated via cardiac parasympathetic pathways, additional sympathetic influences, particularly in the Valsalva maneuver, can alter these responses. We and others have previously classified these tests into parasympathetic and sympathetic, depending on whether heart rate alone or both heart rate and blood pressure control was affected. This approach has proved to be extremely useful clinically because it reflects the sequence of damage seen in diabetic subjects and has therefore been widely used. However, we would stress that although clinically useful, such a classification should not be considered physiologically precise because of the complexity of autonomic pathways” (2).
About influential factors of heart rate variability such as body weight, body mass index, insulin resistance, and blood lipid levels (3) that our dear colleagues mentioned, these are not among the variables in our study. We agree these factors can provide complementary information. Therefore, these factors needed to be considered in future studies that will assess the difference between the cardiovascular autonomic function of RA patients and the general population.
References
- 1.Javady Nejad Z, Jamshidi AR, Qorbani M, Ravanasa P. Cardiovascular autonomic neuropathy in rheumatoid arthritis assessed by cardiovascular autonomic function tests: A cross-sectional survey. Anatol J Cardiol. 2015;15:722–6. doi: 10.5152/akd.2014.5635. [CrossRef] [DOI] [PMC free article] [PubMed] [Google Scholar]
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