[Circadian rhythm of the heart rate and autonomic nervous system stimulation tests in patients with systemic lupus erythematosus].

We studied 19 women (mean age 35 +/- 13 years) with systemic lupus erythematosus (SLE), in order to evaluate whether or not alterations in the circadian rhythm of heart rate (HR) occur in patients with pathologic responses to stimulation tests of the autonomic nervous system (ST-ANS). The duration of SLE was 5.3 +/- 5 years. None of the patients had clinical signs of cardiopathy or dysautonomy, nor were any of them taking drugs with known effects on the heart or ANS. Nine patients (47%, group A) had normal ST-ANS and 10 (53%, group B) had an abnormal response to at least 1 ST-ANS (5 to sympathetic ANS, 3 to parasympathetic and 2 to both ST-ANS). Age, duration of disease and therapy were not different between the 2 groups. All patients underwent 24-hour ambulatory ECG monitoring, and chronobiologic analysis of hourly HR was carried out by single and mean cosinor methods. A significant circadian rhythm was found both in the total sample (mesor 80 b/min, acrophase h 13:12; p less than 0.01), and, separately, in group A (mesor 82 b/min, acrophase h 13:11; p less than 0.01) and group B (mesor 78 b/min, acrophase h 13:12; p less than 0.01). No difference existed between the HR circadian rhythms of the 2 groups. Thus, our data show the possibility of ANS involvement in SLE patients without clinical signs of dysautonomy; the analysis of the HR circadian rhythm does not appear to be a sensitive method to identify early involvement of the ANS in these patients.