Impaired cardiovascular autonomic nervous system function in patients with Churg-Strauss syndrome

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.

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).

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.

The CSS patients show impaired HRV parameters, indicating parasympathetic ANS dysfunction in addition to peripheral nervous system involvement.