Cardiac Function at Rest and with Exercise in the Chronic Fatigue Syndrome

Section: S Prevalence Of Oi In Cfs Patientssupporting

confidence: 93%

Hemodynamic and neurohumoral responses to head-up tilt in patients with chronic fatigue syndrome

Timmers

Wieling

Soetekouw

et al. 2002

“…Some have used postural challange to show that patients with CFS develop hypotension or tachycardia [6][7][8][9]. Others have used exercise testing and their data also suggest cardiovascular dysfunction [21,22]. Some could demonstrate a decreased heart rate variability in rest or during paced breathing, using spectral analysis of RR intervals [23][24][25], reflecting a possible decreased vagal tone.…”

Section: Discussionmentioning

confidence: 99%

Autonomic function in patients with chronic fatigue syndrome

Soetekouw

Lenders

Bleijenberg

et al. 1999

Subtle signs of autonomic dysfunction and orthostatic intolerance have been reported in patients with chronic fatigue syndrome (CFS). To assess cardiovascular autonomic function noninvasively in an unselected group of patients with CFS, we examined responsiveness to several cardiovascular reflex tests in 37 CFS patients and 38 healthy control subjects. Blood pressure and heart rate (HR) were recorded continuously by a Finapres device before and during forced breathing, standing up, Valsalva maneuver, and sustained handgrip exercise (HG). In addition, a mental arithmetic test was carried out and questionnaires to assess the severity of CFS symptoms were completed. At rest, there were no significant differences in blood pressure or in HR between the two groups. The in- and expiratory difference in HR tended to be lower in CFS patients (28.4 +/- 10.5 beats) than in healthy controls (32.2 +/- 9.5) (p = 0.11). The maximal increase in HR during standing up was not significantly different between the CFS group (37.6 +/-8.9 beats) and the control group (40.2 +/- 8.9 beats). There were no significant differences between both groups with regard to the Valsalva ratio, but the systolic and diastolic blood pressure responses were significantly larger in CFS patients, despite the fact that many CFS patients were not able to sustain the Valsalva maneuver. The HR response to MA was significantly less in the CFS group (22.6 +/- 9.9) than in the control group (29.5 +/- 16.7) (p < 0.05), suggesting impaired cardiac sympathetic responsiveness to mental stress. The lower HR responses could not be explained by the level of concentration in the CFS group. During HG exercise, the hemodynamic responses were lower in the CFS group than in the control group, but this might be attributed to the lower level of muscle exertion in CFS patients. There were no significant differences between CFS patients with and without symptoms of autonomic dysfunction regarding the hemodynamic responses to the cardiovascular reflex tests. The findings of the study suggest that there are no gross alterations in cardiovascular autonomic function in patients with CFS.

“…These include striated muscle deficiencies, but skeletal muscle energetics, structure and histopathology, physiology [17][18][19][20], and glycolytic activity [21] have been normal while electromyographic results have been inconclusive [22]. Also, cardiovascular investigations have not demonstrated defects in day-to-day cardiac fitness among CFS patients compared to other unconditioned people [23]. Infectious and immune pathology have often been suspected but have not been conclusively demonstrated as major etiologic factors [24][25][26].…”

Section: Overall Heart Rate Variability Response With Syncope Is Blunmentioning

confidence: 99%

Neurally mediated hypotension and autonomic dysfunction measured by heart rate variability during head-up tilt testing in children with chronic fatigue syndrome

Stewart

Weldon

Arlievsky

et al. 1998

Recent investigations suggest a role for neurally mediated hypotension (NMH) in the symptomatology of chronic fatigue syndrome (CFS) in adults. Our previous observations in children with NMH and syncope (S) unrelated to CFS indicate that the modulation of sympathetic and parasympathetic tone measured by indices of heart rate variability (HRV) is abnormal in children who faint during head-up tilt (HUT). In order to determine the effects of autonomic tone on HUT in children with CFS we performed measurements of HRV during HUT in 16 patients aged 11-19 with CFS. Data were compared to 26 patients evaluated for syncope and with 13 normal control subjects. After 30 minutes supine, patients were tilted to 80 degrees for 40 minutes or until syncope occurred. Time domain indices included RR interval, SDNN, RMSSD, and pNN50. An autoregressive model was used to calculate power spectra. LFP (.04-.15 Hz), HFP (.15-.40Hz), and TP (.01-.40Hz). Data were obtained supine (baseline) and after HUT. Thirteen CFS patients fainted (CFS+, 5/13 pure vasodepressor syncope) and three patients did not (CFS-). Sixteen syncope patients fainted (S+, all mixed vasodepressor-cardioinhibitory) and 10 did not (S-). Four control patients fainted (Control+, all mixed vasodepressor-cardioinhibitory) and nine did not (Control-). Baseline indices of HRV were not different between Control+ and S+, and between Control- and S-, but were depressed in S+ compared to S-. HRV indices were strikingly decreased in CFS patients compared to all other groups. With tilt, SDNN, RMSSD, and pNN50 and spectral indices decreased in all groups, remaining much depressed in CFS compared to S or control subjects. With HUT, sympathovagal indices (LFP/HFP, nLFP, and nHFP) were relatively unchanged in CFS, which contrasts with the increase in nLFP with HUT in all other groups. With syncope RMSSD, SDNN, LFP, TP, and HFP increased in S+ (and Control+), suggesting enhanced vagal heart rate regulation. These increases were not observed in CFS+ patients. CFS is associated with NMH during HUT in children. All indices of HRV are markedly depressed in CFS patients, even when compared with already low HRV in S+ or Control+ patients. Sympathovagal balance does not shift toward enhanced sympathetic modulation of heart rate with HUT and there is blunting in the overall HRV response with syncope during HUT. Taken together these data may indicate autonomic impairment in patients with CFS.