Aug 2026· Revue neurologique (Paris)· 0 citations· 33 references
Medicine
TL;DR
Findings support the value of routine HRV and Ewing's battery assessment in Morvan syndrome for early detection of cardiovascular autonomic involvement and improved clinical monitoring.
Abstract
Background
AND
Objective
Morvan syndrome is a rare neurological disorder characterized by peripheral nerve hyperexcitability, autonomic instability, and encephalopathy. Autonomic dysfunction in these patients may have important cardiovascular implications. We characterized cardiovascular autonomic function in Morvan syndrome and compared it with that of healthy controls.
Methods
In this comparative cross-sectional study, 19 patients with Morvan syndrome and 24 healthy controls broadly comparable in age at the group level were evaluated. Heart rate variability (HRV) was assessed using non-invasive electrocardiography, including time-domain and frequency-domain measures. Autonomic function was evaluated using Ewing's battery, including heart-rate response to deep breathing, Valsalva maneuver, orthostatic testing, and isometric handgrip.
Results
Morvan syndrome patients showed significant autonomic impairment compared with healthy controls. HRV parameters, including standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), total power, low-frequency power, and high-frequency power, were significantly reduced in patients. Ewing's battery also demonstrated marked abnormalities, including reduced deep-breathing difference, lower Valsalva ratio, impaired orthostatic blood pressure response, and diminished isometric handgrip response. Effect sizes ranged from moderate to large (0.504-0.934), indicating substantial clinical relevance. Disease duration showed significant negative correlations with several HRV indices, including RMSSD (r=-0.68, P=0.001), suggesting progressive autonomic impairment.
Conclusion
Morvan syndrome patients demonstrated significant cardiovascular autonomic dysfunction compared with healthy controls, reflected by impaired HRV and abnormal autonomic reflex testing. These findings support the value of routine HRV and Ewing's battery assessment in Morvan syndrome for early detection of cardiovascular autonomic involvement and improved clinical monitoring.
OBJECTIVE
We aimed to evaluate multi-domain autonomic function in patients with spontaneous intracranial hypotension (SIH) and investigate its association with clinical and radiological features.
BACKGROUND
SIH often presents with orthostatic symptoms that overlap with autonomic disorders; however, the prevalence and distribution of autonomic dysfunction in SIH remain poorly characterized.
METHODS
In this cross-sectional study conducted at a tertiary care center in Seoul, Republic of Korea, 34 patients with imaging-confirmed SIH underwent a comprehensive autonomic function testing between October 2024 and February 2025. The autonomic function testing battery included heart rate response to deep breathing, Valsalva maneuver, head-up tilt test, and quantitative sudomotor axon reflex test. Hemodynamic responses during head-up tilt were monitored using both intermittent brachial and continuous beat-to-beat blood pressure measurements. Autonomic abnormalities were determined using age- and sex-matched Korean normative data.
RESULTS
All enrolled patients presented with extradural fluid collection on spinal magnetic resonance imaging, indicating SIH due to dural tears. Autonomic dysfunction was identified in 18 of 34 (52.9%) of patients in the orthostatic domain, nine of 34 (26.5%) in the cardiovagal domain, and 10 of 34 (29.4%) in the sudomotor domain. Postural orthostatic tachycardia syndrome was the most frequent orthostatic abnormality, observed in 12 of 34 (35.3%) patients, followed by classical orthostatic hypotension in four of 34 (11.8%), syncope in one of 34 (2.9%), and delayed orthostatic hypotension in one of 34 (2.9%). No significant associations were identified between domains of autonomic dysfunction and the clinical or imaging features of SIH in false discovery rate-corrected analyses.
CONCLUSION
In patients with SIH due to dural tears, orthostatic hemodynamic abnormalities were common, with postural orthostatic tachycardia syndrome being the most frequent phenotype.
Woo-Seok Ha, D. Jung, Sojung Yoon et al.· Headache· 0 citations
Background: Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity, and autonomic nervous system dysfunction may contribute to this risk. The relationship between autonomic abnormalities and RA disease activity, however, remains incompletely defined.
Objectives: To assess cardiovascular autonomic function in patients with RA using autonomic reflex tests, heart rate variability (HRV), and the Composite Autonomic Symptom Score-31 (COMPASS-31), and to examine differences across disease activity categories.
Methods: This cross-sectional analysis included the 93 patients with RA enrolled in a study at AIIMS Bhopal. Cardiovascular autonomic reflex testing, five-minute resting HRV, and COMPASS-31 were assessed at baseline. Disease activity was categorised using the Clinical Disease Activity Index (CDAI). Continuous outcomes were compared using the Kruskal-Wallis test. Categorical autonomic-test classifications were compared using Pearson chi-square testing, with an exact test used when expected cell counts were small. Post-hoc pairwise comparisons were adjusted for multiple testing.
Results: The mean age was 47.8 ± 11.0 years and 83.9% of participants were female. Low, moderate, and high disease activity were present in 16.1%, 55.9%, and 28.0%, respectively. The continuous 30:15 ratio differed across disease activity groups (P = 0.042), although no pairwise comparison remained significant after Holm adjustment. For categorical autonomic-test classifications, the 30:15 ratio (P = 0.040) and Valsalva response (P < 0.001) differed significantly across disease activity groups; the Valsalva difference was driven primarily by the moderate-versus-high comparison. Orthostatic hypotension did not reach significance when analysed using an exact test (P = 0.051). HRV parameters and COMPASS-31 scores did not differ significantly across disease activity groups.
Conclusion: Abnormal cardiovascular autonomic reflex responses were frequent within this RA cohort, particularly for parasympathetic tests. Selected reflex-test measures differed by disease activity, whereas resting HRV and COMPASS-31 did not. The non-linear and method-dependent pattern suggests that autonomic involvement in RA is complex and is not uniformly captured by a single assessment modality.
S. Isac, A. Ganguly, Loveleen Kaur et al.· International Journal of Med...· 0 citations
Cardiac autonomic tone and its relation with physical fitness level in healthy medical students was evaluated to provide important data regarding autonomic status and physical status which will be useful for both clinical and research purposes.
Sailesh Chaudhary, G. J. Shah, Sanjog Bam et al.· Journal of Nepalgunj Medical...· 0 citations
OBJECTIVES
Patients with long coronavirus disease (COVID) experience disabling fatigue, autonomic dysfunction, reduced exercise capacity and post-exertional malaise (PEM). Heart rate variability (HRV) can evaluate autonomic function and monitor overexertion, potentially helping to mitigate PEM. This study aimed to use continuous multi-day HRV recordings to monitor overexertion and study autonomic function in long COVID.
METHOD
Heart rate and HRV were continuously measured in 121 patients with long COVID (43 ± 11 years, 32% male) and 21 healthy controls (42 ± 13 years, 48% male), with daily life activities tracked in a logbook. Participants underwent a (sub)maximal cardiopulmonary exercise test to determine heart rate at the first ventilatory threshold (VT1) to study HRV responses to exercise at different intensities.
RESULTS AND DISCUSSION
HRV was lower in patients with long COVID compared with healthy controls during various daily activities and sleep (p = 0.027). Across all exercise intensities surrounding the VT1, HRV remained lower for 24 h in patients compared with controls (p = 0.010). Nighttime HRV decreased with intense exercise and longer durations in patients with long COVID (p = 0.018), indicative of exercise-induced diurnal disturbances of the autonomic nervous system in long COVID.
CONCLUSION
Heart rate variability, assessed by wearables, suggests autonomic dysfunction in patients with long COVID. The delayed recovery of the sympathovagal balance after exercise close to and above VT1, suggests that the risk of PEM rises above VT1.
APPLICATION
These results confirm the applicability of wearables to assess autonomic function and manage overexertion in patients with long COVID.
Twan M Ruijgt, Anouk Slaghekke, Anneke Ellens et al.· Sports Medicine· 0 citations
Background: Phase-Rectified Signal Averaging (PRSA) methods, Deceleration (DC), and Acceleration Capacity (AC), provide a comprehensive assessment of cardiac autonomic function (CAN). There are no published studies comparing PRSA methods with conventional methods such as Time Domain Heart Rate Variability (TD-HRV) or Cardiac Autonomic Reflex Tests (CARTs), nor have they described a cut-off value for AC and DC to distinguish patients with CAN (+ve) from those without CAN (-ve). Our study compares PRSA methods with conventional methods and defines cut-off values for AC and DC to diagnose CAN. Methodology: We studied two cohorts: 126 individuals with normal ventricular function (derivation cohort) and 143 individuals with Left Ventricular Dysfunction (validation cohort). These patients underwent CARTs and supine, resting ECG recordings for 2 to 3 minutes. The patients were categorized as CAN +Ve and CAN -Ve based on TD-HRV parameters and the CARTs. Two different CART criteria were studied: the All-India Institute of Medical Sciences (AIIMS-AFT) criteria and the 2011 Toronto Consensus recommendations. Patients with and without CAN were segregated by AC and DC values, and the methods were compared. The cutoff values for DC and AC were calculated using the ROC curve method from the derivation cohort and verified in the validation cohort. Results: A reduction in DC values and an increase in AC values indicate a higher chance of CAN. The cut-off values of -7 for AC and 7 for DC provide the highest accuracy in detecting CAN prevalence. Both values have an AUC of nearly 0.9. Reclassifying both Cohorts as CAN +Ve based on the derived cut-offs and comparing with the prevalence determined by conventional methods results in kappa values ranging from 0.5 to 0.7. Conclusions: A decrease in DC value and an increase in AC value are associated with a higher probability of CAN. An AC value ≥ -7 and a DC value ≤ 7 indicate good accuracy in identifying CAN.
Stigi Joseph, A. Sudhakar, JK Mukkadan· Nigerian Medical Journal· 0 citations
Objective To determine whether cardiovascular autonomic neuropathy (CAN) and reduced heart rate variability (HRV) predict the development of distal symmetrical polyneuropathy (DSPN) in individuals with diabetes mellitus (DM). Methods A total of 288 individuals with DM (mean age 58.1 ± 13.4 years, 41.3% women, 78.5% with type 2 diabetes) underwent baseline assessment of CAN using cardiovascular autonomic reflex tests and HRV indices (CVRR, rMSSD, high- and low-frequency power). DSPN was characterized using three definitions: (i) clinical criteria based on symptoms and signs, (ii) the sensory-loss phenotype derived from quantitative sensory testing, and (iii) the Toronto consensus definition requiring abnormal nerve conduction plus symptoms or signs. A total of 194 participants without DSPN at baseline were followed for 3.0 ± 1.3 years to assess incident DSPN. Results At baseline, CAN prevalence was 16.3%, and low HRV indices were present in 18.6–40.2% of participants. DSPN prevalence was 27.7%, 17.6%, and 20.8% for definitions (i), (ii), and (iii), respectively. Cross-sectionally, CAN and reduced HRV were associated with DSPN (unadjusted ORs 1.8–4.0), with associations largely persisting after adjustment. Incident DSPN occurred at 8.4, 5.7, and 3.3 per 100 person-years. Baseline CAN independently predicted incident DSPN (adjusted HRs 6.20, 3.30, and 7.33 across definitions). Lower rMSSD, HF power, and LF power predicted incident DSPN according to definitions (i) and (iii), whereas reduced CVRR predicted DSPN defined by criteria (ii). Conclusions Established CAN is a strong predictor of future DSPN. Reduced HRV provides a practical, accessible alternative marker for identifying individuals at elevated neuropathy risk.
Dimitrios Tsilingiris, D. Schmalzridt, O. Eldesouky et al.· Frontiers in Endocrinology· 0 citations
