Autonomic nervous system dysfunction in sclerodermic and primary Raynaud’s phenomenon

Abstract

Our aim was to investigate the sympathetic hyperactivity of systemic sclerosis that may lead to greater morbidity and mortality from cardiovascular events. We analysed the sympathetic (low-frequency) and vagal (high-frequency) components of heart rate variability, in supine and upright positions, in 10 patients with systemic sclerosis, 12 patients with primary Raynaud's phenomenon and 14 controls. We also analysed lung function in order to evaluate a possible link between heart rate variability and ventilation parameters. Heart rate variability was reduced in the supine position in subjects with systemic sclerosis both in comparison with primary Raynaud's phenomenon (total power: 1103+/-156 versus 3302+/-486 ms2, P<0.004) and control subjects (3148+/-422 ms2, P<0.002). Low-frequency power was higher in patients with systemic sclerosis than in the controls (54.5+/-4.5 versus 42.5+/-3.5 normalized units, P<0.01). During tilt, the change in heart rate was +44% in controls, +24% in subjects with primary Raynaud's phenomenon, and only +17% in the patients with systemic sclerosis (P<0.01 versus controls). In patients with systemic sclerosis we found a significant correlation between high-frequency power and the indices of lung function (residual volume: r2=0.5143, P<0.01; total lung capacity: r2=0.5142, P<0.01, vital capacity: r2=0.3789, P<0.05). Heart rate variability was reduced and sympathetic output increased in patients with systemic sclerosis. Subjects with primary Raynaud's phenomenon were characterized by normal heart rate variability and by some degree of sympathetic hyperactivity. During tilting, subjects with systemic sclerosis maintained an unmodified heart rate variability, thus suggesting an impaired baroceptor modulation of the autonomic control. The negative correlation between high-frequency power and indices of respiratory insufficiency in patients with systemic sclerosis suggests that the pulmonary structure plays an important role in the modulation of heart rate variability.

Left atrial phasic function and heart rate variability in patients with systemic sclerosis: A new part of the old puzzle

“…However, in the frequency domain analysis, the HF power is affected more than LF power, which results in significant increase of HF/LF ratio that provides information on the sympathovagal imbalance in the SSc group. This further indicates a predominance of sympathetic nervous activity in these patients, which was previously found by other investigators, and which could partly explain the higher incidence of atrial and ventricular arrhythmias in the SSc subjects.…”

Transcutaneous Electrical Nerve Stimulation (TENS) Improves Upper GI Symptoms and Balances the Sympathovagal Activity in Scleroderma Patients

“…One group has reported increased sympathetic activity in SSc patients in the supine position [40]. However, this increase was based on the normalized value of the sympathetic activity rather than the absolute value, which was in fact decreased similarly to our results and others.…”

“…Another group has reported a decrease in all HRV parameters in SSc patients in the time but not the frequency domain [35]. Other studies have not demonstrated a significant difference in the sympathovagal balance in SSc patients compared to normal controls, under baseline conditions [36][37][38][39][40].…”

Evolution of blood pressure and cholesterol in stage 1 hypertension: role of autonomic nervous system activity

“…Decreased HRV with dominant vagal impairment has been found in individuals with coronary artery disease [26] or acute myocardial infarction [27], and in both clinical settings this condition is associated with an adverse prognosis. A profound decrease in HRV total power has been found in individuals with scleroderma, and this was accompanied by sympathetic predominance [28].…”