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Introduction. The manifestations of autonomic nervous system (ANS) dysfunction in autoimmune diseases have been the subject of many studies. However, the published results pertaining to such research are controversial. Sudden cardiac death due to fatal arrhythmias is frequent in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Objective. To analyze risk predictors of sudden cardiac death related to the degree of autonomic dysfunction. Methods. We performed cardiovascular ANS assessment in 90 patients in this case-controlled study, including 52 (6 male, 46 female) patients with SLE, 38 (6 male, 32 female) with RA and 41 (23 male, 17 female) healthy subjects. The methodology included a comprehensive ECG analysis (with Schiller software AT-10) of QTc interval, late potentials, short-term heart rate variability (HRV) and nonlinear HRV (Poincare plot) analysis; 24-hour Holter ECG monitoring with ECG QTc interval analysis, HRV analysis; 24-hour blood pressure monitoring with systolic and diastolic blood pressure variability; cardiovascular autonomic reflex tests (according to Ewing). Vagal dysfunction was established by performing 3 tests: Valsalva maneuver, deep breathing test and heart rate response to standing test. Dysfunction of the sympathetic nervous system was examined by applying 2 tests: blood pressure response to standing and handgrip test. Results. In all cardiovascular reflex tests, the frequencies of abnormal results were significantly higher among the patients than among the healthy subjects. Severe autonomic dysfunction was more common in RA. QTc interval was more prolonged in patients with SLE. Both diseases were associated with depressed heart rate variability compared to controls, the reduction being greater in RA patients. In the patients with SLE, autonomic dysfunction is predominantly with higher sympathetic activity while in RA vagal predominance is evident. Conclusion. SLE and RA are associated with severe autonomic dysfunction and the presence of significant risk predictors related to the onset of sudden cardiac death.

Introduction. Cardiovascular autonomic modulation is altered in patients with essential hypertension. Objective To evaluate acute and long-term effects of amlodipine on cardiovascular autonomic function and haemodynamic status in patients with mild essential hypertension. Methods. Ninety patients (43 male, mean age 52.12 ±10.7) years with mild hypertension were tested before, 30 minutes after the first 5 mg oral dose of amlodipine and three weeks after monotherapy with amlodipine. A comprehensive study protocol was done including finger blood pressure variability (BPV) and heart rate variability (HRV) beat-to-beat analysis with impedance cardiography, ECG with software short-term HRV and nonlinear analysis, 24-hour Holter ECG monitoring with QT and HRV analysis, 24-hour blood pressure (BP) monitoring with systolic and diastolic BPV analysis, cardiovascular autonomic reflex tests, cold pressure test, mental stress test. The patients were also divided into sympathetic and parasympathetic groups, depending on predominance in short time spectral analysis of sympathovagal balance according to low frequency and high frequency values. Results. We confirmed a significant systolic and diastolic BP reduction, and a reduction of pulse pressure during day, night and early morning hours. The reduction of supraventricular and ventricular ectopic beats during the night was also achieved with therapy, but without statistical significance. The increment of sympathetic activity in early phase of amlodipine therapy was without statistical significance and persistence of sympathetic predominance after a few weeks of therapy detected based on the results of short-term spectral HRV analysis. All time domain parameters of long-term HRV analysis were decreased and low frequency amongst spectral parameters. Amlodipne reduced baroreflex sensitivity after three weeks of therapy, but increased it immediately after the administration of the first dose. Conclusion. The results of the study showed that amlodipine affected autonomic modulation as a shift to sympathetic hyperactivity, but without statistical significance. In the selected group of patients with vagal predominance in sympathovagal balance, amlodipine increased sympathetic and decreases vagal activity. Therefore we conclude that amlodipine mostly exerts impact on autonomic function modulation in patients with vagal predominance in resting state.