Objectives: Although peripheral nervous system involvement in patients with Churg-Strauss syndrome (CSS) has been described, little is known about its autonomic part. Autonomic nervous system (ANS) function can be assessed by studying heart rate variability (HRV) and a decrease in the spectrum of HRV correlates with ANS impairment.
Methods: Out of 24 CSS patients we chose 12 (four males, eight females, aged 40 ± 8.3 years) in disease remission and without cardiac involvement. Twelve age- and sex-matched healthy volunteers served as a control group. All underwent 24-h electrocardiogram (ECG) Holter recordings. HRV was calculated from 1-h segments, including: total power (TP), ultra-low frequency (ULF), very low frequency (VLF), low frequency (LF), and high frequency (HF) powers as well as normalized LF (LF%) and HF (HF%) powers and the LF to HF power ratio (LF/HF).
Results: The CSS patients showed decreased HRV parameters in the 1-h domains: TP (2038 vs. 3622 ms(2), p = 0.001), HF (561 vs. 1574 ms(2), p < 0.001), LF (672 vs. 1050 ms(2), p < 0.01), and VLF (544 vs. 738 ms(2), p = 0.016). However, LF% and LF/HF ratio were markedly higher in CSS patients than in controls (53.4% vs. 39%, p < 0.001 and 1.1 vs. 0.64, p < 0.001), whereas HF% was lower in CSS than in controls (46.6% vs. 61%, p < 0.001). These results were independent of duration of the disease, eosinophil count, corticosteroids, or peripheral nerve involvement in the past.
Conclusions: The CSS patients show impaired HRV parameters, indicating parasympathetic ANS dysfunction in addition to peripheral nervous system involvement.