Evaluation of cardiac autonomic functions in patients with systemic lupus erythematosus.

BACKGROUND: Cardiovascular involvement is one of the leading causes of death among patients with systemic lupus erythematosus (SLE). In this study, we aimed to investigate cardiac autonomic functions in SLE patients.

METHODS: We enrolled 36 patients (25 female; mean age 34.2 ± 10.2 years) with SLE and 32 healthy subjects (23 female; mean age 35.0 ± 10.3 years). All participants underwent 24-h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting first, second, and third-minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV), heart rate turbulence (HRT) and QT dispersion analysis. The mean SLE duration was 8.4 ± 4.0 years.

RESULTS: According to the baseline demographic characteristics, both groups were similar with regard to age, gender, body mass index and left ventricular ejection fraction. Mean HRR1 (32.6 ± 10.9 vs. 42.5 ± 6.5, p = 0.038), HRR2 (51.0 ± 16.9 vs. 61.0 ± 10.8, p = 0.01) and HRR3 (52.8 ± 17.5 vs. 65.8 ± 9.8, p < 0.001) values were significantly higher in control group. When HRV was considered, SDNN, SDANN, RMSSD, PNN50 and high frequency (HF) component were significantly decreased in patients with SLE compared with healthy controls, but low frequency (LF) component and LF/HF were significantly higher in SLE patients. In addition, HRT onset and HRT slope values were significantly less negative in SLE patients. QT dispersion was significantly greater in SLE patients than healthy subjects (81.3 ± 15.8 vs. 53.2 ± 13.1, p < 0.001).

CONCLUSION: Our study results suggest that cardiac autonomic functions are impaired in SLE patients despite the absence of overt cardiac involvement and symptoms. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired autonomic functions in patients with SLE.