RT Journal Article SR Electronic T1 Abnormalities of cardiovascular neural control and reduced orthostatic tolerance in patients with primary fibromyalgia. JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 1787 OP 1793 VO 32 IS 9 A1 Raffaello Furlan A1 Simona Colombo A1 Francesca Perego A1 Fabiola Atzeni A1 Alessandro Diana A1 Franca Barbic A1 Alberto Porta A1 Fabio Pace A1 Alberto Malliani A1 Piercarlo Sarzi-Puttini YR 2005 UL http://www.jrheum.org/content/32/9/1787.abstract AB OBJECTIVE: Fibromyalgia (FM) is a syndrome characterized by widespread musculoskeletal pain. Symptoms of orthostatic intolerance may also be present, suggesting underlying abnormalities of cardiovascular neural regulation. We tested the hypothesis that FM is characterized by sympathetic overactivity and alterations in cardiovascular autonomic response to gravitational stimulus. METHODS: Sixteen patients with primary FM and 16 healthy controls underwent electrocardiography examination, finger blood pressure, respiration, and muscle sympathetic nerve activity (MSNA) recordings at rest and during stepwise tilt test, up to 75 degrees . The autonomic profile was assessed by MSNA, plasma catecholamine, and spectral indices of cardiac sympathetic (LFRR in normalized units, NU) and vagal (HFRR both in absolute and NU) modulation and of sympathetic vasomotor control (LFSAP) computed by spectrum analysis of RR and systolic arterial pressure (SAP) variability. Arterial baroreflex function was evaluated by the SAP/RR spontaneous-sequences technique, the index a, and the gain of MSNA/diastolic pressure relationship during stepwise tilt test. RESULTS: At rest, patients showed higher values of heart rate, MSNA, LFRR NU, LF/HF, LFSAP, and reduced HFRR than controls. During tilt test, lack of increase of MSNA, less decrease of HFRR, and excessive rate (44%) of syncope were found in patients, suggesting reduced capability to enhance the sympathetic activity to vessels and withdraw the vagal modulation to sino-atrial node. Baroreflex function was similar in both groups. CONCLUSION: Patients with FM have an overall enhancement of cardiovascular sympathetic activity while recumbent. Lack of increased sympathetic discharge to vessels and decreased cardiac vagal activity characterize their autonomic profile during tilt test, and might account for the excessive rate of syncope.