The cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia: Associations with pain, affective impairments, sleep problems, and fatigue

Abstract

This study investigated the cardiac, vasomotor, and myocardial branches of the baroreflex in fibromyalgia using the spontaneous sequence method. Systolic blood pressure (SBP), interbeat interval (IBI), stroke volume (SV), pre‐ejection period (PEP), and total peripheral resistance (TPR) were continuously recorded in 40 fibromyalgia patients and 30 healthy individuals during a cold pressor test and a mental arithmetic task. Sequences of covariation between SBP and IBI (cardiac branch), SV and PEP (myocardial branch), and TPR (vasomotor branch) were identified. Baroreflex sensitivity (BRS) was represented by the slope of the regression line between values in the sequences; baroreflex effectiveness (BEI) was indexed by the proportion of progressive SBP changes that elicited reflex responses. Patients exhibited lower BRS in the three branches, lower BEI in the cardiac and vasomotor branches, and reduced reactivity in cardiac BRS and BEI, SBP, IBI, SV, and PEP. Moreover, BRS and BEI were inversely related to clinical pain, cold pressor pain, depression, trait anxiety, sleep problems, and fatigue. Reduced function of the three baroreflex branches implies diminished resources for autonomic inotropic, chronotropic, and vascular regulation in fibromyalgia. Blunted stress reactivity indicates a limited capacity for autonomic cardiovascular adjustment to situational requirements. The associations of BRS and BEI with pain perception may reflect the antinociceptive effects arising from baroreceptor afferents, where reduced baroreflex function may contribute to the hyperalgesia characterizing fibromyalgia. The associations with affective impairments, sleep problems, and fatigue suggest that baroreflex dysfunctions are also involved in the secondary symptoms of the disorder.

The Role of Depressive Disorders in Autonomic Cardiovascular Dysregulation in Fibromyalgia

“…During resting conditions and low psychophysiological activation, IBI almost entirely depends on parasympathetic activity (37), such that the subgroup difference in this parameter also confirms lower parasympathetic influences in individuals with depression. As the main mechanism of short-term BP regulation, the cardiac baroreflex responds to BP fluctuations with compensatory adjustments of HR, myocardial contractility, and vasomotor tone (17); BRS, as assessed in this study, reflects the strength of the compensatory HR response transmitted by vagal inputs on the sinus node. Therefore, the BRS reduction in FM patients with depressive disorders but not in those without depressive disorders also supports the conclusion that depressive disorders are relevant to the reduced parasympathetic control seen in individuals with FM (58).…”

“…Moreover, several studies pointed toward blunted cardiovascular reactivity to physical and mental stressors in individuals with FM, reflected in diminished responses in IBI, HRV, blood pressure (BP), BRS, and indicators of sympathetic cardiac control, like the preejection period (PEP) and stroke volume (SV) (12)(13)(14)(17)(18)(19)(20). With respect to FM pathology, cardiovascular dysregulations were considered to be implicated in hyperalgesia, as well as other characteristic symptoms like affective impairments, sleep problems, and fatigue (13,14,17,21).…”

Effect of Cognitive-Behavioral Therapy on Nocturnal Autonomic Activity in Patients with Fibromyalgia: A Preliminary Study

“…Considering that an association between HRV and disability has been reported in other pain conditions [ 67 , 68 ], this assessment would have helped to better describe our sample and to control its impact on the treatment outcome results. Finally, the interpretation of LF and the LF/HF ratio are discussed in the scientific literature [ 16 , 69 , 70 ]. However, this is not the case for HF, whose interpretation is easier.…”

“…Consistently, Furlan, et al 2005 [ 17 ], showed, with microneurography—the reference method for sympathetic activity in humans—that FM patients exhibited higher values of muscle sympathetic nerve activity (MSNA) associated with normalized LF, LF/HF and lower HF in comparison with controls. This autonomic imbalance was found at rest, but many studies showed reduced sympathetic reactivity to stress in this clinical population [ 7 , 8 , 14 , 15 , 16 ].…”

“…By contrast, increases in the low-frequency to high-frequency ratio (LF/HF ratio)—and sometimes in low-frequency power (LF)—have been shown, illustrating sympathetic predominance in cardiac control in FM patients [ 9 , 10 , 12 , 13 ]. However, LF is considered to be determined by the parasympathetic nervous system, and LF and the LF/HF ratio are limited markers of cardiac sympathetic activity [ 14 , 15 , 16 ]. Consistently, Furlan, et al 2005 [ 17 ], showed, with microneurography—the reference method for sympathetic activity in humans—that FM patients exhibited higher values of muscle sympathetic nerve activity (MSNA) associated with normalized LF, LF/HF and lower HF in comparison with controls.…”